Typically we will attach the mouseover and mouseout client-side events on the gridview rows to highlight rows on mouseover, but there are cases that we don't want to make the row highlighted when we are on edit mode. To do this we can check the GridView EditIndex to determine if the row is on edit mode and then do the validation there. Here's a sample code block below of what I am talking about: protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.DataRow)...