[rmnr]

كود :

Private Sub DataGridView1_CellFormatting(sender As Object, e As DataGridViewCellFormattingEventArgs) Handles DataGridView1.CellFormatting
   If e.ColumnIndex = 0 Then '0 = العمود الأول
       If Not IsNothing(e.Value) AndAlso e.Value.ToString.Length > 18 Then
           e.Value = e.Value.ToString.Substring(0, 18)
       End If
   End If
End Sub