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How To Use Data Link Files with the OleDbConnection Object in Visual C# .NET
Article ID: 308426 - View products that this article applies to.
This article was previously published under Q308426
This article demonstrates how to use an OLE DB Universal Data Link (.udl) file to specify the connection string that an ADO.NET OleDbConnection object uses to establish a database connection.
OLE DB Universal Data Link (.udl) files provide a convenient way to create and verify an ActiveX Data Objects (ADO) connection string that is used to connect to an OLE DB data source. The connection string information is persisted in a specific format to a file with the .udl extension. You can reference a .udl file in the ConnectionString property of an ADO.NET OleDbConnection object to specify the connection string that the object should use to connect to a database. Use the File Name parameter of the connection string to specify the name of the .udl file that contains the connection string information.
It is important to note the following information, which is taken from the "OleDbConnection.ConnectionString Property" article in the .NET Framework Class Library documentation (see the References section):
To reference a Microsoft Data Link (UDL), add a reference to the UDL to the ConnectionString in the form "File Name = myfile.udl". If more than one UDL is specified in the connection string, only the last occurrence is loaded. If you specify a UDL, and subsequently call the OleDbConnection object to retrieve the ConnectionString, the ConnectionString contains the reference to the UDL file, not the contents of the file. Connection strings that contain UDLs are parsed each time the OleDbConnection is opened. Because this can affect performance, a ConnectionString that does not reference a UDL is recommended.
For more information about the OleDbConnection.ConnectionString property, see the following .NET Framework Class Library documentation:
http://msdn.microsoft.com/en-us/library/system.data.oledb.oledbconnection.connectionstring.aspxFor additional information, click the article number below to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/189680/EN-US/ )How To Use Data Link Files with ADO