private void DataGridView1_CellValidating(object sender, DataGridViewCellValidatingEventArgs e) { if (DataGridView1[e.ColumnIndex, e.RowIndex].IsInEditMode) { if (DataGridView1[e.ColumnIndex, e.RowIndex].ValueType == typeof(int)) { Control c = DataGridView1.EditingControl; int tempVar = 0; if (!(int.TryParse(c.Text, out tempVar))) { MessageBox.Show("Must be numeric"); e.Cancel = true; DataGridView1.CancelEdit(); } } } }