[除錯] DataGridView1.CurrentRow with EVENT DataGridView1_SelectionChanged

問題(problem):
點選 DataGridView 的表頭(Header)會錯誤 

錯誤訊息(Error Msg):
並未將物件參考設定為物件的執行個體

Private Sub DataGridView1_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataGridView1.SelectionChanged
   
     '出錯的Code
     If DataGridView1.CurrentRow.Index <> -1 Then
           'do something
     End If
     
     '改成物件是否 Nothing
      If DataGridView1.CurrentRow IsNot Nothing Then
           'do something
      End If
End Sub

或改成


'確定是否點選到DataGridView的某行資料列 [C#]
if (this.DataGridView.SelectedRows.Count != 0) {}

DataGridView - EditOnEnter
DataGridView 控制項 (Windows Form)