使用MySql.Data设置conn_attrs（program_name）报错，求解决方案

问题说明 #

想要在MySQL连接中设置程序名称，尝试通过拼接conn_attrs=program_name:alireza到连接字符串的方式实现，代码如下：

var builder = new MySqlConnectionStringBuilder()
{
    Server = "myip",
    UserID = "myuser",
    Password = "mypass",
    Database = "mydb",
    SslMode = MySqlSslMode.Required,
    ConnectionTimeout = 30,
    CharacterSet = "utf8mb4",
};

var cs = $"{builder.ConnectionString};conn_attrs=program_name:alireza";
using var conn = new MySqlConnection(cs);
using var cmd = new MySqlCommand("Select BookId From Books", conn);
conn.Open();
using var reader = await cmd.ExecuteReaderAsync();
while(await reader.ReadAsync())
{
    int id = reader.GetInt32(0);
}

运行时触发错误：

Option not supported.
Parameter name: conn_attrs

使用的NuGet包版本：

• MySql.Data Version=8.0.32
• MySql.Data.EntityFramework Version=8.0.32

解决方案 #

方法一：使用官方支持的ApplicationName属性 #

MySql.Data驱动原生支持通过ApplicationName连接字符串参数设置程序名称，该参数会自动映射到MySQL的program_name连接属性。直接在MySqlConnectionStringBuilder中设置即可：

var builder = new MySqlConnectionStringBuilder()
{
    Server = "myip",
    UserID = "myuser",
    Password = "mypass",
    Database = "mydb",
    SslMode = MySqlSslMode.Required,
    ConnectionTimeout = 30,
    CharacterSet = "utf8mb4",
    ApplicationName = "alireza" // 设置程序名称
};

using var conn = new MySqlConnection(builder.ConnectionString);
using var cmd = new MySqlCommand("Select BookId From Books", conn);
conn.Open();
using var reader = await cmd.ExecuteReaderAsync();
while(await reader.ReadAsync())
{
    int id = reader.GetInt32(0);
}

方法二：连接后设置会话变量 #

如果需要更灵活的设置，可以在连接打开后执行SQL语句设置program_name会话变量：

var builder = new MySqlConnectionStringBuilder()
{
    Server = "myip",
    UserID = "myuser",
    Password = "mypass",
    Database = "mydb",
    SslMode = MySqlSslMode.Required,
    ConnectionTimeout = 30,
    CharacterSet = "utf8mb4",
};

using var conn = new MySqlConnection(builder.ConnectionString);
conn.Open();

// 设置程序名称会话变量
using var setProgramCmd = new MySqlCommand("SET SESSION program_name = 'alireza';", conn);
await setProgramCmd.ExecuteNonQueryAsync();

// 执行业务查询
using var cmd = new MySqlCommand("Select BookId From Books", conn);
using var reader = await cmd.ExecuteReaderAsync();
while(await reader.ReadAsync())
{
    int id = reader.GetInt32(0);
}

说明 #

MySql.Data 8.0.32版本的连接字符串不支持conn_attrs参数，该参数属于MySQL原生协议字段，但驱动并未将其暴露为连接字符串选项，而是通过ApplicationName属性提供了等价的功能。

内容的提问来源于stack exchange，提问作者Alireza Noori