TextBoxBase.BeginChange 方法
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
開始變更區塊。
public:
void BeginChange();public void BeginChange ();member this.BeginChange : unit -> unitPublic Sub BeginChange ()範例
下列範例示範如何使用 BeginChange 和 EndChange 方法來建立變更區塊。
TextBox myTextBox = new TextBox();
// Begin the change block. Once BeginChange() is called
// no text content or selection change events will be raised
// until EndChange is called. Also, all edits made within
// a BeginChange/EndChange block are wraped in a single undo block.
myTextBox.BeginChange();
// Put some initial text in the TextBox.
myTextBox.Text = "Initial text in TextBox";
// Make other changes if desired...
// Whenever BeginChange() is called EndChange() must also be
// called to end the change block.
myTextBox.EndChange();
Dim myTextBox As New TextBox()
' Begin the change block. Once BeginChange() is called
' no text content or selection change events will be raised
' until EndChange is called. Also, all edits made within
' a BeginChange/EndChange block are wraped in a single undo block.
myTextBox.BeginChange()
' Put some initial text in the TextBox.
myTextBox.Text = "Initial text in TextBox"
' Make other changes if desired...
' Whenever BeginChange() is called EndChange() must also be
' called to end the change block.
myTextBox.EndChange()
備註
注意
當您呼叫 BeginChange 時，也必須呼叫 EndChange 來完成變更區塊，否則會擲回例外狀況。
變更區塊會以邏輯方式將多個變更分組成單一復原單位，並防止在變更區塊之後引發文字內容或選取範圍變更事件。 如此一來，您就可以對文字元素進行多個編輯，而不會讓另一個接聽程式同時變更文字元素的危險。 變更區塊是藉由呼叫 DeclareChangeBlock 方法來建立。 BeginChange呼叫 方法會導致指定的變更區塊中包含所有後續變更，直到對 方法的對應呼叫 EndChange 完成為止。