howto make usage of Gridview DateKeyNames

if (e.Row.RowType == DataControlRowType.DataRow)
{
string keyStringValueA = GridView1.DataKeys[e.Row.RowIndex].Values["YourDataKeyName"].ToString();
string keyIntegerValueB = GridView1.DataKeys[e.Row.RowIndex].Values["YourDataKeyName"].ToString();

int n = int.Parse(dkk);

once you know it its simple and works fine :-)