The less intuitive code works

Please look at this method that looks intuitive but not working, I want to use a one parameter search method when search word is not empty and the parameterless method  when it is empty I wrote these two methods that are not working because select parameter doesn't added or removed in the selecting method:
 
Protected Sub objWebUploadLog_Selecting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ObjectDataSourceSelectingEventArgs) Handles objWebUploadLog.Selecting If SearchWord = "" Then If objWebUploadLog.SelectParameters("search") Is Nothing Then Else objWebUploadLog.SelectParameters.Remove(objWebUploadLog.SelectParameters("search")) End If objWebUploadLog.SelectMethod = "GetWebUploadLogByUserID" objWebUploadLog.SelectCountMethod = "GetWebUploadLogCountByUserID" ...