Question

VB一个简单的键盘按键响应程序

'打开一个新的工程并将变量 ShiftKey 添加到窗体的声明部分中：

'将 Textbox 控件添加到窗体上并将此过程添加到 KeyDown 事件中：
Private Sub Text1_KeyDown(KeyCode As Integer, Shift As Integer)
Dim ShiftKey As Integer
ShiftKey = Shift And 7
Select Case ShiftKey
Case 1 ' 或 vbShiftMask
Label1.Caption = "You pressed the SHIFT key."
Case 2 ' 或 vbCtrlMask
Label1.Caption = "You pressed the CTRL key."
Case 4 ' 或 vbAltMask
Label1.Caption = "You pressed the ALT key."
Case 3
Label1.Caption = "You pressed both SHIFT and CTRL."
Case 5
Label1.Caption = "You pressed both SHIFT and ALT."
Case 6
Label1.Caption = "You pressed both CTRL and ALT."
Case 7
Label1.Caption = "You pressed SHIFT, CTRL, and ALT."
End Select
End Sub
为什么要Shift And 7？而不是 Shift？感谢各位对菜鸟的回答。

Answer 1

因为vbShiftMask,vbCtrlMask,vbAltMask是按位排列的，即2^n(n=0,1,2),分别为1，2，4，像这种情况，程序处理的时候就要用到位运算符(And)来处理这种数据。这个程序可以简化，你看看下面的。组合键情况显示在窗体Caption里。
代码如下。
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
Dim s As String
If (Shift And vbShiftMask) = vbShiftMask Then s = s & "SHIFT" & " "
If (Shift And vbCtrlMask) = vbCtrlMask Then s = s & "CTRL" & " "
If (Shift And vbAltMask) = vbAltMask Then s = s & "ALT" & " "
Caption = s
End Sub

Answer 2

因为CTRL ALT SHIFT 是组合键