c#.net语句e.Row.RowType == DataControlRowType.DataRow是什么含义?

c#.net语句e.Row.RowType == DataControlRowType.DataRow是什么含义?
事件语句
protected void GridView1_RowDataBound(object sender,GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
e.Row.Cells[3].Text = Convert.ToDateTime(e.Row.Cells[3].Text).ToShortDateString();
}
}
中
e.Row.RowType
DataControlRowType.DataRow又表示什么?