一般我們能過vs2005的sql explorer來添加一個本地的mdf文件。也許你可能會出現下面這個問題：
exception details: system.data.sqlclient.sqlexception: the user instance login flag is not supported on this version of sql server. the connection will be closed.

通過搜索。發現這里有我們所需要的信息：error message: the user instance login flag is not supported on this version of sql server. the connection will be closed

仔細分析scott的回答：

"the issue is that user instancing, which allows the automatic creation of databases from code, isn't support on the full version of sql 2005.  that is a function of sql express only.  the solution is to manually create the database in sql server 2005 and set a connection string to point to it.  you will also need to run aspnet_regsql.exe manually against the database if you will be using any of the new built-in database features of asp.net v2.0."

因此，如果我們不是使用的從ms下載下來的sql server 2005 express，那么我們只能過過在sql2005管理器上把mdf文件添加進去在連接它。

解決方法：在sql2005管理器上，通過attach（附加）本地的mdf文件成功之后。在vs2005的sql explorer的連接即可。

以后繼續補充。

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