where is hittest and mouseup/down events on datagrid?

[Al Knowles]

I am very new to dotnet, so please bear with me. I have a datagrid
derived from System.Web.UI.WebControls. I want to detect when the user
has clicked on a given header column. All that I am reading on the net
indicates that I should use the mousedown or mouseup event of the
datagrid control and examine a property of the datagrid_event_argument
called hittest.

I cannot find any mousedown or mouseup event for my datagrid. It's not
listed as an event in the drop down list under Visual Studio, nor could
I find it under the HTML view.

Assistance would be greatly appreciated.

Thanks in advance.