Deleting Problems..

here i a again.. because im really having problems in deleting rows from a gridview... here is my code

SelectCommand="SELECT UserId, First, Last, Email, CreateDate, LastLoginDate, IsApproved, IsLockedOut FROM aspnet_Membership"

DeleteCommand="DELETE FROM aspnet_Membership WHERE [UserId] = @UserId"

ConnectionString="<%$ ConnectionStrings:ConnectionString2 %>" >

<DeleteParameters>

<asp:Parameter Name="UserId" Type="Int32"/>

</DeleteParameters>

 

It is working but when i click the delete button.. this appears
Must declare the scalar variable "@UserId".

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Must declare the scalar variable "@UserId".

Source Error:





An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:





[SqlException (0x80131904): Must declare the scalar variable "@UserId".]
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +95
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +82
System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +346
System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +3430
System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async) +271
System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) +367
System.Data.SqlClient.SqlCommand.ExecuteNonQuery() +149
System.Web.UI.WebControls.SqlDataSourceView.ExecuteDbCommand(DbCommand command, DataSourceOperation operation) +492
System.Web.UI.WebControls.SqlDataSourceView.ExecuteDelete(IDictionary keys, IDictionary oldValues) +919
System.Web.UI.DataSourceView.Delete(IDictionary keys, IDictionary oldValues, DataSourceViewOperationCallback callback) +176
System.Web.UI.WebControls.GridView.HandleDelete(GridViewRow row, Int32 rowIndex) +911
System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +1067
System.Web.UI.WebControls.GridView.RaisePostBackEvent(String eventArgument) +214
System.Web.UI.WebControls.GridView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +31
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +32
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +242
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3839
need help asap.. pls THANK YOU VERY MUCH!!!