实时框架代码的动态连接字符串首先在运行时为多个数据库提供程序提供EF6（mssql，mysql，oracle）

Question

我正在尝试使用实体框架代码第一个模型连接多个数据库提供程序，通过动态生成连接字符串。但它没有按预期工作。

以下是要审核的代码：

 switch (providerName)
        {
            case "System.Data.SqlClient":
                entityBuilder = new EntityConnectionStringBuilder();
                entityBuilder.Provider = providerName;
                //ConfigurationManager.ConnectionStrings["mssql"].ConnectionString
                break;
            case "MySql.Data.MySqlClient":
                entityBuilder = new EntityConnectionStringBuilder();
                entityBuilder.Provider = providerName;
                //ConfigurationManager.ConnectionStrings["mysql"].ConnectionString
                break;
            default:
                break;
        }

        switch (providerName)
        {
            case "System.Data.SqlClient":
                conn = new SqlConnectionStringBuilder(entityBuilder.ProviderConnectionString)
                {

                    UserID = databaseUserId,
                    Password = databasePassword,
                    DataSource = serverName,
                    IntegratedSecurity = false,
                    InitialCatalog = databaseName

                }.ConnectionString;

                break;
            case "MySql.Data.MySqlClient":
                conn = new MySql.Data.MySqlClient.MySqlConnectionStringBuilder(entityBuilder.ProviderConnectionString)
                {
                    Server = serverName,
                    UserID = databaseUserId,
                    Password = databasePassword,
                    Database = databaseName,
                    PersistSecurityInfo = true

                }.ConnectionString;
                break;
            default:
                break;
        }

Web.config

<entityFramework> <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework"> <parameters> <parameter value="mssqllocaldb" /> </parameters> </defaultConnectionFactory> <providers> <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" /> <provider invariantName="MySql.Data.MySqlClient" type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6, Version=6.9.9.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d"></provider></providers> </entityFramework>

 <DbProviderFactories>
  <remove invariant="MySql.Data.MySqlClient" />
  <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.9.9.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
</DbProviderFactories>

DbContext构造函数

  ` public partial class ModelCodeFist : DbContext
{
    public ModelCodeFist(string connection)
        : base(connection)
    {
    }
}

`

另外如何在运行时更改默认提供程序，因为EF将sql连接器作为defaultConnectionFactory

动态连接到mssql正在运行，但是对于 mysql，它产生错误，因为默认连接器仍然是sqlclient ，请查看下面的图片：

如果我错过了什么，请告诉我 谢谢！

Answer 1

您想要创建自己的ProviderFactory，实现IDbConnectionFactory

public class MyProviderFactory : IDbConnectionFactory
{    
    public DbConnection CreateConnection(string nameOrConnectionString)
    {
        if ("mySqlName".equals(nameOrConnectionString))
        {
            return new MySqlConnection("<Connection String>");
        }
        else 
        {
            return new SqlConnection("<Connection String>");
        }
    }
}

然后在app.config中将其设置为DefaultConnectionFactory

<defaultConnectionFactory type="MyAssmebly.MyProviderFactory, MyAssmebly">
  <parameters>

未经过测试的代码，当然没有经过性能测试！