连接MySQL数据库得到错误“Unable to find the requested .Net Framework Data Provider”

Each .NET Framework data provider that supports a factory-based class registers configuration information in the DbProviderFactories section of the machine.config file on the local computer. The following configuration file fragment shows the syntax and format for .

<system.data>
    <DbProviderFactories>
        <add name="MySQL Data Provider"
            invariant="MySql.Data.MySqlClient"
            description=".Net Framework Data Provider for MySQL"
            type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.7.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
    </DbProviderFactories>
</system.data>