vb中怎么用撤消命令??

来源：百度知道 编辑：UC知道 时间：2024/05/29 05:47:45
在一个text1中输入字符，点击button1全部复制到剪贴版，再点击button2粘贴到text2上，然后按button3.返回text2上一步操作
请问怎么做

'窗体声明部分
Private Const WM_USER = &H400
Private Const WM_PASTE = &H302
Private Const EM_UNDO = WM_USER + 23
Private Declare Function SendMessageBynum& Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long)

'text1中文本全部复制到剪贴版
Private Sub Command1_Click()
Clipboard.Clear
Clipboard.SetText Text1.Text

End Sub

'剪贴版中文本全部粘贴到text2,覆盖原内容
Private Sub Command2_Click()
Text2.SelStart = 0
Text2.SelLength = Len(Text2.Text)
SendMessageBynum& Text2.hwnd, WM_PASTE, 0&, 0&

End Sub

'返回text2上一步操作
Private Sub Command3_Click()
SendMessageBynum& Text2.hwnd, EM_UNDO, 0&, 0&

End Sub

dim a
a=text1
command2_click()
text2=a
text1=""
end sub
command3_click()
text1=a
end sub
这是思路，具体的你再改下