动态改变数据库连接 in Entity Framework 5

 今天把silverlight 升级到5，ADO.ENT EF也用NUGet升级到5.结果发现5下的EF默认没有4的那种分部方法了。

当然你可以把生成器的属性里面，生成代码的属性替换为default，默认为Note。也可以跟4版本一样有分部方法。

但我发现EF5下面更智能，。更好用。EF的链接字符串有相关的类

EntityConnection

可以操作了。

请参看MSDN:

 http://msdn.microsoft.com/en-us/library/system.data.entityclient.entityconnection.connectionstring.aspx

这样动态改变数据库就可以变得更灵活。

只要自定义一个方法，然后返回字符串给EntityConnection链接即可

// Specify the provider name, server and database. 
string providerName = "System.Data.SqlClient";
string serverName = ".";
string databaseName = "AdventureWorks";

// Initialize the connection string builder for the 
// underlying provider.
SqlConnectionStringBuilder sqlBuilder =
    new SqlConnectionStringBuilder();

// Set the properties for the data source.
sqlBuilder.DataSource = serverName;
sqlBuilder.InitialCatalog = databaseName;
sqlBuilder.IntegratedSecurity = true;

// Build the SqlConnection connection string. 
string providerString = sqlBuilder.ToString();

// Initialize the EntityConnectionStringBuilder.
EntityConnectionStringBuilder entityBuilder =
    new EntityConnectionStringBuilder();

//Set the provider name.
entityBuilder.Provider = providerName;

// Set the provider-specific connection string.
entityBuilder.ProviderConnectionString = providerString;

// Set the Metadata location.
entityBuilder.Metadata = @"res://*/AdventureWorksModel.csdl|
                            res://*/AdventureWorksModel.ssdl|
                            res://*/AdventureWorksModel.msl";
Console.WriteLine(entityBuilder.ToString());