What to use to select between data sources in PageIndexChanging in gridview

Question

I have a gridview that has paging enabled. The problem is depending on what the user clicks there are a couple of different ways to populate the datasource for the gridview.

So, if pages are generated I'm not sure how to differentiate between the datasources in the PageIndexChanging method of the gridview.

Ex.

  /// <summary>
/// PageIndexChanging
/// </summary>
protected void grdvStats_PageIndexChanging(object sender, GridViewPageEventArgs e)
{      
    // If gridview populated via this button click...
    // else poplulated via this linkbutton
}