private void SetColError ( DataRow myRow, int colIndex ) {
   string errorString;
   errorString = "Your error text here.";
   // set the error for the specified column of the row.
   myRow.SetColumnError ( colIndex, errorString );
}

private void PrintColError ( DataRow myRow, int colIndex ) {
   // print the error of a specified column.
   Response.Write ( myRow.GetColumnError ( colIndex ) );
}

Private Sub SetColError ( ByVal myRow As DataRow, ByVal colIndex As Integer )
   Dim errorString As String 
   errorString = "Your error text here."
   ' set the error for the specified column of the row.
   myRow.SetColumnError ( colIndex, errorString )
End Sub

Private Sub PrintColError ( ByVal myRow As DataRow, ByVal colIndex As Integer )
   ' print the error of a specified column.
   Response.Write ( myRow.GetColumnError ( colIndex ) )
End Sub