连接字符串使用模型优先，数据库优先为同一数据库，

本文关键字：数据库 字符串 连接 模型 | 更新日期: 2023-09-27 17:50:55

在Asp.net Entity框架中，我们对同一个数据库使用Model优先，DB优先，有两个连接字符串模型第一，数据库第一。那么我们如何为模型优先，数据库优先创建单个连接字符串呢?

连接字符串使用模型优先，数据库优先为同一数据库，

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，如果你足够勇敢，你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:

或者，您可以采取相反的方法，让我们保留EntityConnectionString并从中提取SqlConnectionString:

string entityConnectionString = 'xxxxxxx';
EntityConnectionStringBuilder entityBuilder = new EntityConnectionStringBuilder(entityConnectionString);
string sqlConnectionString = entityBuilder.ProviderConnectionString;

连接字符串将是不同的:DB第一个将在开始时具有元数据[嵌入]位置。你可以把"普通的"Code First连接字符串放到web上。配置并在DB First DbContext构造函数中添加"元数据部分"，使用静态方法构建所需的EntityConnectionString。

的例子:

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();
}

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