Sendkeys 和 Sendmessage 使用技巧一例

Private Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long

Function sqrx(ByVal x As Double) As String '计算平方根（比VB DOUBLE 类型精度高）
Dim temp As String, i As Long, j As Long
Shell "Calc.EXE", vbMinimizedNoFocus '运行计算器
temp = x & "y0.5="

For i = 1 To Len(temp)
SendKeys Mid(temp, i, 1), True '向计算器顺序发送按键消息X (X^Y) 0.5=
Next

temp = String(64, Chr(0))
i = FindWindow(vbNullString, "计算器") '窗口句柄
j = FindWindowEx(i, ByVal 0&, "Edit", vbNullString) '编辑框句柄
SendMessage j, &HD, Len(temp), ByVal temp '发送编辑框文本至temp
SendKeys "%{F4}", True '调用ALT+F4关闭计算器窗口
sqrx = temp
End Function

Private Sub Command1_Click()
Dim i As Integer
For i = 17 To 24
Debug.Print "sqrx(" & i & ")=" & sqrx(i)
Next
End Sub