连接字符串，以同时使用“模型”和“ DB”用于同一数据库，

Question

在Asp.net实体框架中，对于同一个数据库，我们首先使用Model，首先使用DB，并且首先使用DB，首先使用两个连接字符串。 因此，我们如何为Model首先，DB首先创建单个连接字符串。

Answer 1

连接字符串将有所不同：第一个数据库的开头将具有元数据[embedded]位置。 您可以使用静态方法来构建所需的EntityConnectionString，将“正常”的Code First连接字符串放在web.config中，并在DB First DbContext构造函数中添加“元数据部分”。

例：

public MyContext() : base(BuildConnectionString())
{
}

private static string BuildConnectionString()
{
  varsqlBuilder = new SqlConnectionStringBuilder();
  //dinamically prepare the provider connection string here, using the CF one in the web.config 
  //[..]

  //now build the entity connection string, using the one just built as ProviderConnectionString
  var entityBuilder = new EntityConnectionStringBuilder();
  entityBuilder.ProviderConnectionString = sqlBuilder.ToString();
  entityBuilder.Metadata = "res://*/";
  entityBuilder.Provider = "System.Data.SqlClient";

  return entityBuilder.ToString();
}

Answer 2

您可以使用EntityConnectionStringBuilder ：

string sqlConnectionString = "Data Source=localhost;
     Initial Catalog=AdventureWorks;Integrated Security=True;Connection Timeout=60;multipleactiveresultsets=true"

string providerName = "System.Data.SqlClient";    

EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder();
entityBuilder.Provider = providerName;
entityBuilder.ProviderConnectionString = sqlConnectionString;
entityBuilder.Metadata = @"res://*/AdventureWorksModel.csdl|
                        res://*/AdventureWorksModel.ssdl|
                        res://*/AdventureWorksModel.msl";

string entityConnectionString = entityBuilder.ToString();

或者，如果您足够勇敢，则可以尝试重新格式化entityConnectionString：

string sqlConnectionString = "Data Source=localhost;
     Initial Catalog=AdventureWorks;Integrated Security=True;Connection Timeout=60;
     multipleactiveresultsets=true"

string entityConnectionString = 
  string.Format("metadata=.\AdventureWorks.csdl|.\AdventureWorks.ssdl|.\AdventureWorks.msl; provider=System.Data.SqlClient;provider connection string='{0}'" providerName=\"System.Data.EntityClient\"",
    sqlConnectionString
 );

编辑：

另外，您可以采取相反的方法，让EntityConnectionString并从中提取SqlConnectionString：

string entityConnectionString = 'xxxxxxx';
EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder(entityConnectionString);

string sqlConnectionString = entityBuilder.ProviderConnectionString;