conversion error

Please help.

I have an aspx page with a drop down list(ddlCategories), and a datalist(dlLinks). The drop down lists data property is a uniqueidentifier from a table.

When an item in the list is selected it fires the following:
SqlLinks.SelectParameters("CategoryID").DefaultValue = ddlCategories.SelectedValue
dlLinks.DataBind()

The sqldatasource for the datalist runs a stored procedure (below)

sp_GetLinks (@.CategoryID ?) AS

select * from links where category = @.category

My question is, what should @.Category be declared as if the category column in the table is a uniqueidentifier? And what conversion do I need to do I just can't work it out, as I keep getting the following error:

Implicit conversion from data type sql_variant to uniqueidentifier is not allowed. Use the CONVERT function to run this query.

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: Implicit conversion from data type sql_variant to uniqueidentifier is not allowed. Use the CONVERT function to run this query.

Source Error:

Line 5: Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlCategories.SelectedIndexChanged
Line 6: SqlLinks.SelectParameters("CategoryID").DefaultValue = ddlCategories.SelectedValue
Line 7: dlLinks.DataBind()
Line 8: End Sub
Line 9: End Class

Source File:C:\Documents and Settings\Karl Walls\My Documents\My Webs\AFRA\links.aspx.vb Line:7

Stack Trace:

[SqlException (0x80131904): Implicit conversion from data type sql_variant to uniqueidentifier is not allowed. Use the CONVERT function to run this query.]
 System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +177
 System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +68
 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +199
 System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +2305
 System.Data.SqlClient.SqlDataReader.ConsumeMetaData() +31
 System.Data.SqlClient.SqlDataReader.get_MetaData() +62
 System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) +294
 System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +1021
 System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +314
 System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +20
 System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +107
 System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +10
 System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) +7
 System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +139
 System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +139
 System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable) +83
 System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +1659
 System.Web.UI.WebControls.BaseDataList.GetData() +53
 System.Web.UI.WebControls.DataList.CreateControlHierarchy(Boolean useDataSource) +267
 System.Web.UI.WebControls.BaseDataList.OnDataBinding(EventArgs e) +56
 System.Web.UI.WebControls.BaseDataList.DataBind() +62
 links.DropDownList1_SelectedIndexChanged(Object sender, EventArgs e) in C:\Documents and Settings\Karl Walls\My Documents\My Webs\AFRA\links.aspx.vb:7
 System.Web.UI.WebControls.ListControl.OnSelectedIndexChanged(EventArgs e) +75
 System.Web.UI.WebControls.DropDownList.RaisePostDataChangedEvent() +124
 System.Web.UI.WebControls.DropDownList.System.Web.UI.IPostBackDataHandler.RaisePostDataChangedEvent() +7
 System.Web.UI.Page.RaiseChangedEvents() +138
 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +4507

Try to modify the stored procedure as following:

alter proc sp_GetLinks @.Category sql_variant AS
select * from links where category =convert(uniqueidentifier,@.category)
go

|||

Thanks for the reply, before I saw it i removed this line

SqlLinks.SelectParameters("CategoryID").DefaultValue = ddlCategories.SelectedValue

and it worked fine