TDengine.Connector.Async 3.1.3.3

C# Connector

中文版

TDengine.Connector is the C# language connector provided by TDengine. C# developers can use it to develop C# application software that accesses TDengine cluster data.

The TDengine.Connector connector supports establishing a connection with the TDengine running instance through the TDengine client driver (taosc), and provides functions such as data writing, query, data subscription, schemaless data writing, and parameter binding interface data writing. TDengine.Connector also supports WebSocket since v3.0.1, establishes WebSocket connection, and provides functions such as data writing, query, and parameter binding interface data writing.

This article introduces how to install TDengine.Connector in a Linux or Windows environment, and connect to the TDengine cluster through TDengine.Connector to perform basic operations such as data writing and querying.

Notice:

• TDengine.Connector 3.x is not compatible with TDengine 2.x. If you need to use the C# connector in an environment running TDengine 2.x version, please use the 1.x version of TDengine.Connector.
• TDengine.Connector version 3.1.0 has been completely refactored and is no longer compatible with 3.0.2 and previous versions. For 3.0.2 documents, please refer to nuget

The source code of TDengine.Connector is hosted on GitHub.

Supported platforms

The supported platforms are the same as those supported by the TDengine client driver.

Note TDengine no longer supports 32-bit Windows platforms.

Version support

Handling exceptions

TDengine.Connector will throw an exception and the application needs to handle the exception. The taosc exception type TDengineError contains error code and error information, and the application can handle it based on the error code and error information.

TDengine DataType vs. C# DataType

Note: JSON type is only supported in tag.

Installation Steps

Pre-installation preparation

• Install .NET SDK
• Nuget Client (optional installation)
• Install the TDengine client driver. For specific steps, please refer to Installing the client driver

Install the connectors

Nuget package TDengine.Connector can be added to the current project through dotnet CLI under the path of the current .NET project.

dotnet add package TDengine.Connector

You can also modify the .csproj file of the current project and add the following ItemGroup.

   <ItemGroup>
     <PackageReference Include="TDengine.Connector" Version="3.1.*" />
   </ItemGroup>

Establishing a connection

Native connection

var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
using (var client = DbDriver.Open(builder))
{
     Console.WriteLine("connected");
}

WebSocket connection

var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
using (var client = DbDriver.Open(builder))
{
     Console.WriteLine("connected");
}

The parameters supported by ConnectionStringBuilder are as follows:

• protocol: connection protocol, optional value is Native or WebSocket, default is Native
• host: the address of the running instance of TDengine or taosadapter,
• port: The port of the running instance of TDengine or taosadapter.
  • When using WebSocket without SSL, the default is 6041.
  • When using WebSocket with SSL, the default is 443.
• useSSL: Whether to use SSL, the default is false, only valid when the protocol is WebSocket
• token: The token used to connect to TDengine Cloud, only valid when the protocol is WebSocket
• username: username to connect to TDengine
• password: password to connect to TDengine
• db: database connected to TDengine
• timezone: The time zone for parsing time results, the default is TimeZoneInfo.Local, use the TimeZoneInfo.FindSystemTimeZoneById method to parse the string into a TimeZoneInfo object.
• connTimeout: WebSocket connection timeout, only valid when the protocol is WebSocket, the default is 1 minute, use the TimeSpan.Parse method to parse the string into a TimeSpan object.
• readTimeout: WebSocket read timeout, only valid when the protocol is WebSocket, the default is 5 minutes, use the TimeSpan.Parse method to parse the string into a TimeSpan object.
• writeTimeout: WebSocket write timeout, only valid when the protocol is WebSocket, the default is 10 seconds, use the TimeSpan.Parse method to parse the string into a TimeSpan object.
• enableCompression: Whether to enable WebSocket compression (effective for dotnet version 6 and above, connector version 3.1.1 and above). The default is false.
• autoReconnect: Whether to enable WebSocket reconnect (connector version 3.1.3 and above). The default is false.
• reconnectRetryCount: The number of reconnection retries (connector version 3.1.3 and above). The default is 3.
• reconnectIntervalMs: The interval between reconnection retries (connector version 3.1.3 and above). The default is 2000.

Specify the URL and Properties to get the connection

The C# connector does not support this feature

Priority of configuration parameters

The C# connector does not support this feature

Usage examples

Create database and tables

Native Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeQuery
{
    internal class Query
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("create database power");
                    client.Exec("CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSQuery
{
    internal class Query
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("create database power");
                    client.Exec("CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

Insert data

Native Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeQuery
{
    internal class Query
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    string insertQuery =
                        "INSERT INTO " +
                        "power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') " +
                        "VALUES " +
                        "('2023-10-03 14:38:05.000', 10.30000, 219, 0.31000) " +
                        "('2023-10-03 14:38:15.000', 12.60000, 218, 0.33000) " +
                        "('2023-10-03 14:38:16.800', 12.30000, 221, 0.31000) " +
                        "power.d1002 USING power.meters TAGS(3, 'California.SanFrancisco') " +
                        "VALUES " +
                        "('2023-10-03 14:38:16.650', 10.30000, 218, 0.25000) " +
                        "power.d1003 USING power.meters TAGS(2,'California.LosAngeles') " +
                        "VALUES " +
                        "('2023-10-03 14:38:05.500', 11.80000, 221, 0.28000) " +
                        "('2023-10-03 14:38:16.600', 13.40000, 223, 0.29000) " +
                        "power.d1004 USING power.meters TAGS(3,'California.LosAngeles') " +
                        "VALUES " +
                        "('2023-10-03 14:38:05.000', 10.80000, 223, 0.29000) " +
                        "('2023-10-03 14:38:06.500', 11.50000, 221, 0.35000)";
                    client.Exec(insertQuery);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSQuery
{
    internal class Query
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    string insertQuery =
                        "INSERT INTO " +
                        "power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') " +
                        "VALUES " +
                        "('2023-10-03 14:38:05.000', 10.30000, 219, 0.31000) " +
                        "('2023-10-03 14:38:15.000', 12.60000, 218, 0.33000) " +
                        "('2023-10-03 14:38:16.800', 12.30000, 221, 0.31000) " +
                        "power.d1002 USING power.meters TAGS(3, 'California.SanFrancisco') " +
                        "VALUES " +
                        "('2023-10-03 14:38:16.650', 10.30000, 218, 0.25000) " +
                        "power.d1003 USING power.meters TAGS(2,'California.LosAngeles') " +
                        "VALUES " +
                        "('2023-10-03 14:38:05.500', 11.80000, 221, 0.28000) " +
                        "('2023-10-03 14:38:16.600', 13.40000, 223, 0.29000) " +
                        "power.d1004 USING power.meters TAGS(3,'California.LosAngeles') " +
                        "VALUES " +
                        "('2023-10-03 14:38:05.000', 10.80000, 223, 0.29000) " +
                        "('2023-10-03 14:38:06.500', 11.50000, 221, 0.35000)";
                    client.Exec(insertQuery);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

Querying data

Native Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeQuery
{
    internal class Query
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("use power");
                    string query = "SELECT * FROM meters";
                    using (var rows = client.Query(query))
                    {
                       while (rows.Read())
                       {
                           Console.WriteLine($"{((DateTime)rows.GetValue(0)):yyyy-MM-dd HH:mm:ss.fff}, {rows.GetValue(1)}, {rows.GetValue(2)}, {rows.GetValue(3)}, {rows.GetValue(4)}, {Encoding.UTF8.GetString((byte[])rows.GetValue(5))}");
                       }
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSQuery
{
    internal class Query
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("use power");
                    string query = "SELECT * FROM meters";
                    using (var rows = client.Query(query))
                    {
                        while (rows.Read())
                        {
                            Console.WriteLine($"{((DateTime)rows.GetValue(0)):yyyy-MM-dd HH:mm:ss.fff}, {rows.GetValue(1)}, {rows.GetValue(2)}, {rows.GetValue(3)}, {rows.GetValue(4)}, {Encoding.UTF8.GetString((byte[])rows.GetValue(5))}");
                        }
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

execute SQL with reqId

Native Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeQueryWithReqID
{
    internal abstract class QueryWithReqID
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec($"create database if not exists test_db",ReqId.GetReqId());
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSQueryWithReqID
{
    internal abstract class QueryWithReqID
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec($"create database if not exists test_db",ReqId.GetReqId());
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

Writing data via parameter binding

Native Example

using System;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeStmt
{
    internal abstract class NativeStmt
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("create database power");
                    client.Exec(
                        "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                    using (var stmt = client.StmtInit())
                    {
                        stmt.Prepare(
                            "Insert into power.d1001 using power.meters tags(2,'California.SanFrancisco') values(?,?,?,?)");
                        var ts = new DateTime(2023, 10, 03, 14, 38, 05, 000);
                        stmt.BindRow(new object[] { ts, (float)10.30000, (int)219, (float)0.31000 });
                        stmt.AddBatch();
                        stmt.Exec();
                        var affected = stmt.Affected();
                        Console.WriteLine($"affected rows: {affected}");
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSStmt
{
    internal abstract class WSStmt
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("create database power");
                    client.Exec(
                        "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                    using (var stmt = client.StmtInit())
                    {
                        stmt.Prepare(
                            "Insert into power.d1001 using power.meters tags(2,'California.SanFrancisco') values(?,?,?,?)");
                        var ts = new DateTime(2023, 10, 03, 14, 38, 05, 000);
                        stmt.BindRow(new object[] { ts, (float)10.30000, (int)219, (float)0.31000 });
                        stmt.AddBatch();
                        stmt.Exec();
                        var affected = stmt.Affected();
                        Console.WriteLine($"affected rows: {affected}");
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                    throw;
                }
            }
        }
    }
}

Note: When using BindRow, you need to pay attention to the one-to-one correspondence between the original C# column type and the TDengine column type. For the specific correspondence, please refer to TDengine DataType and C# DataType.

Schemaless Writing

Native Example

using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeSchemaless
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            var builder =
                new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                client.Exec("create database sml");
                client.Exec("use sml");
                var influxDBData =
                    "st,t1=3i64,t2=4f64,t3=\"t3\" c1=3i64,c3=L\"passit\",c2=false,c4=4f64 1626006833639000000";
                client.SchemalessInsert(new string[] { influxDBData },
                    TDengineSchemalessProtocol.TSDB_SML_LINE_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_NANO_SECONDS, 0, ReqId.GetReqId());
                var telnetData = "stb0_0 1626006833 4 host=host0 interface=eth0";
                client.SchemalessInsert(new string[] { telnetData },
                    TDengineSchemalessProtocol.TSDB_SML_TELNET_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_MILLI_SECONDS, 0, ReqId.GetReqId());
                var jsonData =
                    "{\"metric\": \"meter_current\",\"timestamp\": 1626846400,\"value\": 10.3, \"tags\": {\"groupid\": 2, \"location\": \"California.SanFrancisco\", \"id\": \"d1001\"}}";
                client.SchemalessInsert(new string[] { jsonData }, TDengineSchemalessProtocol.TSDB_SML_JSON_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_MILLI_SECONDS, 0, ReqId.GetReqId());
            }
        }
    }
}

WebSocket Example

using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSSchemaless
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            var builder =
                new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                client.Exec("create database sml");
                client.Exec("use sml");
                var influxDBData =
                    "st,t1=3i64,t2=4f64,t3=\"t3\" c1=3i64,c3=L\"passit\",c2=false,c4=4f64 1626006833639000000";
                client.SchemalessInsert(new string[] { influxDBData },
                    TDengineSchemalessProtocol.TSDB_SML_LINE_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_NANO_SECONDS, 0, ReqId.GetReqId());
                var telnetData = "stb0_0 1626006833 4 host=host0 interface=eth0";
                client.SchemalessInsert(new string[] { telnetData },
                    TDengineSchemalessProtocol.TSDB_SML_TELNET_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_MILLI_SECONDS, 0, ReqId.GetReqId());
                var jsonData =
                    "{\"metric\": \"meter_current\",\"timestamp\": 1626846400,\"value\": 10.3, \"tags\": {\"groupid\": 2, \"location\": \"California.SanFrancisco\", \"id\": \"d1001\"}}";
                client.SchemalessInsert(new string[] { jsonData }, TDengineSchemalessProtocol.TSDB_SML_JSON_PROTOCOL,
                    TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_MILLI_SECONDS, 0, ReqId.GetReqId());
            }
        }
    }
}

Schemaless with reqId

public void SchemalessInsert(string[] lines, TDengineSchemalessProtocol protocol,
    TDengineSchemalessPrecision precision,
    int ttl, long reqId)

Data Subscription

Create a Topic

Native Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace NativeSubscription
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("create database power");
                    client.Exec("CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                    client.Exec("CREATE TOPIC topic_meters as SELECT * from power.meters");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using System.Text;
using TDengine.Driver;
using TDengine.Driver.Client;

namespace WSSubscription
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("create database power");
                    client.Exec("CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                    client.Exec("CREATE TOPIC topic_meters as SELECT * from power.meters");
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
    }
}

Create a Consumer

Native Example

var cfg = new Dictionary<string, string>()
{
    { "group.id", "group1" },
    { "auto.offset.reset", "latest" },
    { "td.connect.ip", "127.0.0.1" },
    { "td.connect.user", "root" },
    { "td.connect.pass", "taosdata" },
    { "td.connect.port", "6030" },
    { "client.id", "tmq_example" },
    { "enable.auto.commit", "true" },
    { "msg.with.table.name", "false" },
};
var consumer = new ConsumerBuilder<Dictionary<string, object>>(cfg).Build();

WebSocket Example

var cfg = new Dictionary<string, string>()
{
    { "td.connect.type", "WebSocket" },
    { "group.id", "group1" },
    { "auto.offset.reset", "latest" },
    { "td.connect.ip", "localhost" },
    { "td.connect.port","6041"},
    { "useSSL", "false" },
    { "td.connect.user", "root" },
    { "td.connect.pass", "taosdata" },
    { "client.id", "tmq_example" },
    { "enable.auto.commit", "true" },
    { "msg.with.table.name", "false" },
};
var consumer = new ConsumerBuilder<Dictionary<string, object>>(cfg).Build();

The configuration parameters supported by consumer are as follows:

• td.connect.type: connection type, optional value is Native or WebSocket, default is Native
• td.connect.ip: The address of the TDengine running instance or taosadapter
• td.connect.port: The port of the running instance of TDengine or taosadapter.
  • When using WebSocket without SSL, the default is 6041.
  • When using WebSocket with SSL, the default is 443.
• useSSL: Whether to use SSL, the default is false, only valid when the protocol is WebSocket
• token: The token used to connect to TDengine Cloud, only valid when the protocol is WebSocket
• td.connect.user: username to connect to TDengine
• td.connect.pass: Password for connecting to TDengine
• group.id: consumer group ID
• client.id: consumer ID
• enable.auto.commit: Whether to automatically commit offset, the default is true
• auto.commit.interval.ms: The interval for automatically submitting offsets, the default is 5000 milliseconds
• auto.offset.reset: When offset does not exist, where to start consumption, the optional value is earliest or latest, the default is latest
• msg.with.table.name: Whether the message contains the table name
• ws.message.enableCompression: Whether to enable WebSocket compression (effective for dotnet version 6 and above, connector version 3.1.1 and above). The default is false.
• ws.autoReconnect: Whether to enable WebSocket reconnect (connector version 3.1.3 and above). The default is false.
• ws.reconnect.retry.count: The number of reconnection retries (connector version 3.1.3 and above). The default is 3.
• ws.reconnect.interval.ms: The interval between reconnection retries (connector version 3.1.3 and above). The default is 2000.

Supports subscribing to the result set Dictionary<string, object> where the key is the column name and the value is the column value.

If you use object to receive column values, you need to pay attention to:

• There needs to be a one-to-one correspondence between the original C# column type and the TDengine column type. For specific correspondence, please refer to [TDengine DataType and C# DataType] (#tdengine-datatype-and-c-datatype).
• The column name is consistent with the class attribute name and can be get and set.
• Explicitly set the value parser ConsumerBuilder.SetValueDeserializer(new ReferenceDeserializer<T>());

An example is as follows

Result class

     class Result
     {
         public DateTime ts { get; set; }
         public float current { get; set; }
         public int voltage { get; set; }
         public float phase { get; set; }
     }

Set up parser

var tmqBuilder = new ConsumerBuilder<Result>(cfg);
tmqBuilder.SetValueDeserializer(new ReferenceDeserializer<Result>());
var consumer = tmqBuilder.Build();

You can also implement a custom deserializer, implement the IDeserializer<T> interface and pass it in through the ConsumerBuilder.SetValueDeserializer method.

     public interface IDeserializer<T>
     {
         T Deserialize(ITMQRows data, bool isNull, SerializationContext context);
     }

Subscribe to consume data

consumer.Subscribe(new List<string>() { "topic_meters" });
while (true)
{
    using (var cr = consumer.Consume(500))
    {
        if (cr == null) continue;
        foreach (var message in cr.Message)
        {
            Console.WriteLine(
                $"message {{{((DateTime)message.Value["ts"]).ToString("yyyy-MM-dd HH:mm:ss.fff")}, " +
                $"{message.Value["current"]}, {message.Value["voltage"]}, {message.Value["phase"]}}}");
        }
    }
}

Assignment subscription Offset

consumer.Assignment.ForEach(a =>
{
    Console.WriteLine($"{a}, seek to 0");
    consumer.Seek(new TopicPartitionOffset(a.Topic, a.Partition, 0));
    Thread.Sleep(TimeSpan.FromSeconds(1));
});

Commit offset

public void Commit(ConsumeResult<TValue> consumerResult)
public List<TopicPartitionOffset> Commit()
public void Commit(IEnumerable<TopicPartitionOffset> offsets)

Close subscriptions

consumer.Unsubscribe();
consumer.Close();

Full Sample Code

Native Example

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using TDengine.Driver;
using TDengine.Driver.Client;
using TDengine.TMQ;

namespace NativeSubscription
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("CREATE DATABASE power");
                    client.Exec("USE power");
                    client.Exec(
                        "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                    client.Exec("CREATE TOPIC topic_meters as SELECT * from power.meters");
                    var cfg = new Dictionary<string, string>()
                    {
                        { "group.id", "group1" },
                        { "auto.offset.reset", "latest" },
                        { "td.connect.ip", "127.0.0.1" },
                        { "td.connect.user", "root" },
                        { "td.connect.pass", "taosdata" },
                        { "td.connect.port", "6030" },
                        { "client.id", "tmq_example" },
                        { "enable.auto.commit", "true" },
                        { "msg.with.table.name", "false" },
                    };
                    var consumer = new ConsumerBuilder<Dictionary<string, object>>(cfg).Build();
                    consumer.Subscribe(new List<string>() { "topic_meters" });
                    Task.Run(InsertData);
                    while (true)
                    {
                        using (var cr = consumer.Consume(500))
                        {
                            if (cr == null) continue;
                            foreach (var message in cr.Message)
                            {
                                Console.WriteLine(
                                    $"message {{{((DateTime)message.Value["ts"]).ToString("yyyy-MM-dd HH:mm:ss.fff")}, " +
                                    $"{message.Value["current"]}, {message.Value["voltage"]}, {message.Value["phase"]}}}");
                            }
                        }
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
        
        static void InsertData()
        {
            var builder = new ConnectionStringBuilder("host=localhost;port=6030;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                while (true)
                {
                    client.Exec("INSERT into power.d1001 using power.meters tags(2,'California.SanFrancisco') values(now,11.5,219,0.30)");
                    Task.Delay(1000).Wait();
                }
            }
        }
    }
}

WebSocket Example

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using TDengine.Driver;
using TDengine.Driver.Client;
using TDengine.TMQ;

namespace WSSubscription
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                try
                {
                    client.Exec("CREATE DATABASE power");
                    client.Exec("USE power");
                    client.Exec(
                        "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
                    client.Exec("CREATE TOPIC topic_meters as SELECT * from power.meters");
                    var cfg = new Dictionary<string, string>()
                    {
                        { "td.connect.type", "WebSocket" },
                        { "group.id", "group1" },
                        { "auto.offset.reset", "latest" },
                        { "td.connect.ip", "localhost" },
                        { "td.connect.port","6041"},
                        { "useSSL", "false" },
                        { "td.connect.user", "root" },
                        { "td.connect.pass", "taosdata" },
                        { "client.id", "tmq_example" },
                        { "enable.auto.commit", "true" },
                        { "msg.with.table.name", "false" },
                    };
                    var consumer = new ConsumerBuilder<Dictionary<string, object>>(cfg).Build();
                    consumer.Subscribe(new List<string>() { "topic_meters" });
                    Task.Run(InsertData);
                    while (true)
                    {
                        using (var cr = consumer.Consume(500))
                        {
                            if (cr == null) continue;
                            foreach (var message in cr.Message)
                            {
                                Console.WriteLine(
                                    $"message {{{((DateTime)message.Value["ts"]).ToString("yyyy-MM-dd HH:mm:ss.fff")}, " +
                                    $"{message.Value["current"]}, {message.Value["voltage"]}, {message.Value["phase"]}}}");
                            }
                        }
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                    throw;
                }
            }
        }
        
        static void InsertData()
        {
            var builder = new ConnectionStringBuilder("protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata");
            using (var client = DbDriver.Open(builder))
            {
                while (true)
                {
                    client.Exec("INSERT into power.d1001 using power.meters tags(2,'California.SanFrancisco') values(now,11.5,219,0.30)");
                    Task.Delay(1000).Wait();
                }
            }
        }
    }
}

ADO.NET

The C# connector supports the ADO.NET interface, and you can connect to the TDengine running instance through the ADO.NET interface to perform operations such as data writing and querying.

Native Example

using System;
using TDengine.Data.Client;

namespace NativeADO
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            const string connectionString = "host=localhost;port=6030;username=root;password=taosdata";
            using (var connection = new TDengineConnection(connectionString))
            {
                try
                {
                    connection.Open();
                    using (var command = new TDengineCommand(connection))
                    {
                        command.CommandText = "create database power";
                        command.ExecuteNonQuery();
                        connection.ChangeDatabase("power");
                        command.CommandText =
                            "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))";
                        command.ExecuteNonQuery();
                        command.CommandText = "INSERT INTO " +
                                              "power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') " +
                                              "VALUES " +
                                              "(?,?,?,?)";
                        var parameters = command.Parameters;
                        parameters.Add(new TDengineParameter("@0", new DateTime(2023,10,03,14,38,05,000)));
                        parameters.Add(new TDengineParameter("@1", (float)10.30000));
                        parameters.Add(new TDengineParameter("@2", (int)219));
                        parameters.Add(new TDengineParameter("@3", (float)0.31000));
                        command.ExecuteNonQuery();
                        command.Parameters.Clear();
                        command.CommandText = "SELECT * FROM meters";
                        using (var reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                Console.WriteLine(
                                    $"{((DateTime) reader.GetValue(0)):yyyy-MM-dd HH:mm:ss.fff}, {reader.GetValue(1)}, {reader.GetValue(2)}, {reader.GetValue(3)}, {reader.GetValue(4)}, {System.Text.Encoding.UTF8.GetString((byte[]) reader.GetValue(5))}");
                            }
                        }
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                    throw;
                }
            }
        }
    }
}

WebSocket Example

using System;
using TDengine.Data.Client;

namespace WSADO
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            const string connectionString = "protocol=WebSocket;host=localhost;port=6041;useSSL=false;username=root;password=taosdata";
            using (var connection = new TDengineConnection(connectionString))
            {
                try
                {
                    connection.Open();
                    using (var command = new TDengineCommand(connection))
                    {
                        command.CommandText = "create database power";
                        command.ExecuteNonQuery();
                        connection.ChangeDatabase("power");
                        command.CommandText =
                            "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))";
                        command.ExecuteNonQuery();
                        command.CommandText = "INSERT INTO " +
                                              "power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') " +
                                              "VALUES " +
                                              "(?,?,?,?)";
                        var parameters = command.Parameters;
                        parameters.Add(new TDengineParameter("@0", new DateTime(2023,10,03,14,38,05,000)));
                        parameters.Add(new TDengineParameter("@1", (float)10.30000));
                        parameters.Add(new TDengineParameter("@2", (int)219));
                        parameters.Add(new TDengineParameter("@3", (float)0.31000));
                        command.ExecuteNonQuery();
                        command.Parameters.Clear();
                        command.CommandText = "SELECT * FROM meters";
                        using (var reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                Console.WriteLine(
                                    $"{((DateTime) reader.GetValue(0)):yyyy-MM-dd HH:mm:ss.fff}, {reader.GetValue(1)}, {reader.GetValue(2)}, {reader.GetValue(3)}, {reader.GetValue(4)}, {System.Text.Encoding.UTF8.GetString((byte[]) reader.GetValue(5))}");
                            }
                        }
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                    throw;
                }
            }
        }
    }
}

• The connection parameters are consistent with those in Establishing a connection.
• The name of TDengineParameter needs to start with @, such as @0, @1, @2, etc. The value needs to have a one-to-one correspondence between the C# column type and the TDengine column type. For the specific correspondence, please refer to TDengine DataType and C# DataType.

More sample programs

sample program