[除錯] TabControl 內的控制項 與 資料繫結 DataBindings, 卻檢查出空白值！

原因：

1.

控制項(TextBox、ComboBox, etc...) 在TabControl時, 且有資料繫結DataBinding(確實有值)
當儲存(檢查控制項是否空白)時, 卻會檢查出此控制項為空白！

2.

tabPage1有DataGridView綁定 bindingsource

當tabPage2為顯示頁時，此時執行 bindingsource.CancelEdit()

則會引發錯誤:

System.ArgumentOutOfRangeException 未處理

  Message=提供的資料列索引超出範圍。

參數名稱: rowIndex

  Source=System.Windows.Forms

  ParamName=rowIndex

  StackTrace:

       於 System.Windows.Forms.DataGridViewRowCollection.GetRowState(Int32 rowIndex)

解決：how to force all controls on all tab pages of a tab control to load/createhandle at once?
1.
//讓不同的tabPage的Control可以load DataBinding資料
foreach (var v in tabControl1.Controls.OfType<TabPage>())
     v.Show();

2.
執行程式時, 需每個TABPAGE都(手動)點過！

3.
        TabPage1.Show()
        TabPage2.Show()
        TabPage3.Show()
        TabPage4.Show()

4.

dgvM.DataSource = null;

bdNavi.BindingSource.RemoveCurrent();(或 bdNavi.BindingSource.CancelEdit();)  <--- 出錯點

bdNavi.BindingSource.ResetBindings(false);

dgvM.DataSource = bs;

參考：
Update DataGridView but do not select any rows when TabPage entered

From the TabPage documentation Remarks section

Controls contained in a TabPage are not created until the tab page is shown, and any data bindings in these controls are not activated until the tab page is shown.

Contents of tab control aren't loaded unless clicked on

Does data binding work on invisible control?

How to refresh tab that are not shown

Cannot data bind to a control when Control.Visible == false

Forcing a checkbox bound to a DataSource to update when it has not been viewed yet

資料繫結 (Data Binding)(一) 簡單資料繫結
TabControl裡的頁籤內容會跑掉
Control.DataBinding数据绑定细解
不同TabPage下if判斷式沒反應?
Validation for textbox in tabpage