TextBoxBase.CanUndo TextBoxBase.CanUndo TextBoxBase.CanUndo TextBoxBase.CanUndo Property

정의

TextBox 컨트롤에서 이전 작업을 실행 취소할 수 있는지 여부를 나타내는 값을 가져옵니다.Gets a value indicating whether the user can undo the previous operation in a text box control.

public:
 property bool CanUndo { bool get(); };
[System.ComponentModel.Browsable(false)]
public bool CanUndo { get; }
member this.CanUndo : bool
Public ReadOnly Property CanUndo As Boolean

속성 값

TextBox 컨트롤에서 수행한 이전 작업을 실행 취소할 수 있는 경우 true이고, 그렇지 않으면 false입니다.true if the user can undo the previous operation performed in a text box control; otherwise, false.

예제

다음 코드 예제에서는 TextBox, 클래스를 파생 합니다.The following code example uses TextBox, a derived class. 쉽게 Click 에 대 한 이벤트 처리기 MenuItem 잘라내기, 복사, 붙여넣기 및 실행 취소 작업을 수행 하는 개체입니다.It provides Click event handlers for MenuItem objects that perform Cut, Copy, Paste, and Undo operations. 이 예제에서는 한 TextBox 라는 컨트롤 textBox1 만들었습니다.This example requires that a TextBox control named textBox1 has been created.

private:
   void Menu_Copy( System::Object^ sender, System::EventArgs^ e )
   {
      // Ensure that text is selected in the text box.   
      if ( textBox1->SelectionLength > 0 )
      {
         // Copy the selected text to the Clipboard.
         textBox1->Copy();
      }
   }

   void Menu_Cut( System::Object^ sender, System::EventArgs^ e )
   {
      // Ensure that text is currently selected in the text box.   
      if (  !textBox1->SelectedText->Equals( "" ) )
      {
         // Cut the selected text in the control and paste it into the Clipboard.
         textBox1->Cut();
      }
   }

   void Menu_Paste( System::Object^ sender, System::EventArgs^ e )
   {
      // Determine if there is any text in the Clipboard to paste into the text box.
      if ( Clipboard::GetDataObject()->GetDataPresent( DataFormats::Text ) == true )
      {
         // Determine if any text is selected in the text box.
         if ( textBox1->SelectionLength > 0 )
         {
            // Ask user if they want to paste over currently selected text.
            if ( MessageBox::Show( "Do you want to paste over current selection?",
               "Cut Example", MessageBoxButtons::YesNo ) == ::DialogResult::No )
            {
               // Move selection to the point after the current selection and paste.
               textBox1->SelectionStart = textBox1->SelectionStart +
                  textBox1->SelectionLength;
            }
         }
         // Paste current text in Clipboard into text box.
         textBox1->Paste();
      }
   }

   void Menu_Undo( System::Object^ sender, System::EventArgs^ e )
   {
      // Determine if last operation can be undone in text box.   
      if ( textBox1->CanUndo == true )
      {
         // Undo the last operation.
         textBox1->Undo();
         // Clear the undo buffer to prevent last action from being redone.
         textBox1->ClearUndo();
      }
   }
private void Menu_Copy(System.Object sender, System.EventArgs e)
 {
    // Ensure that text is selected in the text box.   
    if(textBox1.SelectionLength > 0)
        // Copy the selected text to the Clipboard.
        textBox1.Copy();
 }
 
 private void Menu_Cut(System.Object sender, System.EventArgs e)
 {   
     // Ensure that text is currently selected in the text box.   
     if(textBox1.SelectedText != "")
        // Cut the selected text in the control and paste it into the Clipboard.
        textBox1.Cut();
 }
 
 private void Menu_Paste(System.Object sender, System.EventArgs e)
 {
    // Determine if there is any text in the Clipboard to paste into the text box.
    if(Clipboard.GetDataObject().GetDataPresent(DataFormats.Text) == true)
    {
        // Determine if any text is selected in the text box.
        if(textBox1.SelectionLength > 0)
        {
          // Ask user if they want to paste over currently selected text.
          if(MessageBox.Show("Do you want to paste over current selection?", "Cut Example", MessageBoxButtons.YesNo) == DialogResult.No)
             // Move selection to the point after the current selection and paste.
             textBox1.SelectionStart = textBox1.SelectionStart + textBox1.SelectionLength;
        }
        // Paste current text in Clipboard into text box.
        textBox1.Paste();
    }
 }
 
 
 private void Menu_Undo(System.Object sender, System.EventArgs e)
 {
    // Determine if last operation can be undone in text box.   
    if(textBox1.CanUndo == true)
    {
       // Undo the last operation.
       textBox1.Undo();
       // Clear the undo buffer to prevent last action from being redone.
       textBox1.ClearUndo();
    }
 }
 
Private Sub Menu_Copy(sender As System.Object, e As System.EventArgs)
    ' Ensure that text is selected in the text box.   
    If textBox1.SelectionLength > 0 Then
        ' Copy the selected text to the Clipboard.
        textBox1.Copy()
    End If
End Sub
 
Private Sub Menu_Cut(sender As System.Object, e As System.EventArgs)
    ' Ensure that text is currently selected in the text box.   
    If textBox1.SelectedText <> "" Then
        ' Cut the selected text in the control and paste it into the Clipboard.
        textBox1.Cut()
    End If
End Sub
 
Private Sub Menu_Paste(sender As System.Object, e As System.EventArgs)
    ' Determine if there is any text in the Clipboard to paste into the text box.
    If Clipboard.GetDataObject().GetDataPresent(DataFormats.Text) = True Then
        ' Determine if any text is selected in the text box.
        If textBox1.SelectionLength > 0 Then
            ' Ask user if they want to paste over currently selected text.
            If MessageBox.Show("Do you want to paste over current selection?", _
                "Cut Example", MessageBoxButtons.YesNo) = DialogResult.No Then
                ' Move selection to the point after the current selection and paste.
                textBox1.SelectionStart = textBox1.SelectionStart + _
                    textBox1.SelectionLength
            End If
        End If 
        ' Paste current text in Clipboard into text box.
        textBox1.Paste()
    End If
End Sub

Private Sub Menu_Undo(sender As System.Object, e As System.EventArgs)
    ' Determine if last operation can be undone in text box.   
    If textBox1.CanUndo = True Then
        ' Undo the last operation.
        textBox1.Undo()
        ' Clear the undo buffer to prevent last action from being redone.
        textBox1.ClearUndo()
    End If
End Sub

설명

이 메서드가 반환 하는 경우 true를 호출할 수 있습니다는 Undo 입력란의 마지막 작업을 취소 하는 방법입니다.If this method returns true, you can call the Undo method to undo the last operation in a text box. 이 메서드를 사용할 수 있습니다는 Popup 의 이벤트를 MenuItem, 또는에서 단추의 상태를 관리 하는 코드는 ToolBar 텍스트 상자 컨트롤에서 이전 작업을 취소 하는 기능을 사용할지 여부를 합니다.You can use this method in the Popup event of a MenuItem, or in code that manages the state of buttons on a ToolBar to enable or disable the ability to undo the previous operation in a text box control.

적용 대상

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