One of the goals that Microsoft has really pushed for in ASP.NET 2.0 is saving the amount of coding necessary to perform common tasks such as data access. On a recent project, I needed the ability to filter the results on a GridView control after I returned the results from my data source. To accomplish this, I added a DropDownList and set the AutoPostBack property on the DropDownList to True. I added two values to the list; one that showed all of the results, and one that showed the filtered result set which in my case was a list of exceptions. I also added a SqlDataSource object called MySqlDataSource. I set the OnChange event to a subroutine similar to below:

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Private Sub FilterDropDownList\_Change(s as Object, e as EventArgs)  
    If FilterDropDownList.SelectedValue = "Filter" then  
        MySqlDataSource.FilterExpression = "MyColumn=1"  
    Else  
        MySqlDataSource.FilterExpression = ""  
    End If  
  
    MyGridView.DataBind  
End Sub

I added the sub MyGridView.DataBind to the subroutine because this subroutine occurs after the SqlDataSource object is created and the resultset is filled. In reality, you only need to perform the MyGridView.DataBind when the FilterExpression value is set to something other than "".