微軟Windows應用編程接口(API)為開發Windows應用程序提供了很多構建好的模塊。它提供各種操作方法，比如獲取鼠標坐標，窗口句柄，顏色等。QTP支持調用動態鏈接庫內定義的這些方法，但是由于VBScript的限制，只有有限的一部分API可以在QTP中使用。
本章使用的API的更多細節和信息可以從MSDN或者Visual Studio的API Viewer工具查詢獲得。
Extern對象
QTP提供一個Extern功能對象用來聲明和調用API。
語法
| Extern.Declare (RetType, MethodName, LibName, Alias [, ArgType(s)]) |
更多細節可參考QTP用戶手冊。
VB API定義語法
| Private Declare Function GetForegroundWindow Lib "user32.dll" () As Long |
對以上API，我們需要使用QTP的Declare方法確定使用的合適參數：
RetType = micLong（函數返回類型）
MethodName = "GetForegroudWindow" （我們可以使用任何其他名字，但是比較好的做法是使用實際API的名字）
LibName = "user32.dll" （如果不是使用Windows系統自帶的DLL,那么文件名必須使用絕對路徑，例如"C:\MyApp\Lib\mylib.dll"）
Alias = "" 或者"GetForegroudWindow"（如果MethodName跟Alias相同，則Alias可以為空值。
ArgType(s) = 本例中不需要傳入參數）。
QTP API定義
| Extern.Declare micLong,"GetForegroundWindow","user32.dll","GetForegroundWindow" |
以下用一些用例來演示使用API解決通常遇到的問題。
問題 17-1.如何判斷當前桌面最上面的為瀏覽器窗口
|
'聲明GetForeGroundWindow API
extern.Declare micLong,"GetForegroundWindow","user32.dll","GetForegroundWindow"
'獲取最前面窗口的句柄
hwnd = extern.GetForegroundWindow()
'判斷是否有包含此句柄的瀏覽器窗口
isBrowser = Browser("hwnd:=" &hwnd).Exist()
If isBrowser then
Msgbox "The top most window is a browser"
End if |
問題 17-2.如何獲得Windows的環境變量 （注意不是QTP環境變量）
|
'變量聲明
Dim s_EnvValue
'聲明 API "GetEnvironmentVariable"
Extern.Declare micLong,"GetEnvironmentVariable","kernel32.dll","GetEnvironmentVariableA", _
micString,micString+micByRef,micLong
'獲取全局變量 "TEMP" 值
Extern.GetEnvironmentVariable "TEMP",s_EnvValue,255 '會得到臨時目錄路徑
MsgBoxs_EnvValue |
問題 17-3.如何使用Windwos API選中Listbox里的選項（item）
|
' 聲明API
Extern.Declare micLong,"SendMessage","user32.dll","SendMessageA",micLong,micLong,micLong,micLong
' 設置Listbox選項item的消息
Const LB_SETSEL = &H185
'方法：根據index選中復選框
Function CheckListBox(hwnd, index)
extern.SendMessagehwnd, LB_SETSEL, True, index
end function
'方法：根據index取消選中復選框
Function UnCheckListBox(hwnd, index)
extern.SendMessagehwnd, LB_SETSEL, False, index
end function |
問題 17-4.如何取到一個文本框的背景色 （當驗證必填項跟可選項底色不同時可用到）
|
'聲明需要的 API
Extern.Declare micLong,"GetPixel","gdi32","GetPixel",micLong,micLong,micLong
Extern.Declare micLong,"GetWindowDC","user32","GetWindowDC",micLong
Extern.Declare micLong,"ReleaseDC","user32","ReleaseDC",micLong,micLong
Extern.Declare micLong,"GetDC","user32","GetDC",micLong
Extern.Declare micLong,"SetForegroundWindow","user32","SetForegroundWindow",micLong
Dim hDCSource
Dim hWndSource
Dim backColor
'取得控件的句柄
hWndSource = Window("Window").WinEdit("MandatoryField1").GetROProperty("hwnd")
'將窗口置于最上面,因為GetPixel方法只能針對可見像素使用
extern.SetForegroundWindowhWndSource
'取得設備上下文句柄
hDCSource = Clng(Extern.GetDC(hWndSource))
'取得相關控件的像素(1,1)點的背景色
backColor = Clng(Extern.GetPixel(hDCSource, Clng(1),Clng(1)))
MsgBoxbackColor
'釋放設備上下文句柄
Extern.ReleaseDChWndSource, hDCSource |
問題 17-5.如何使用Windows API模擬鍵盤操作
|
'聲明API：鍵盤事件keybd_event
extern.Declare micVoid,"keybd_event","user32" ,"keybd_event", _
micbyte,micbyte,miclong,miclon
'聲明API：虛擬按鍵碼映射MapVirtualKey
extern.Declare micLong,"MapVirtualKey","user32","MapVirtualKeyA", _
micLong, micLong
Const KEYEVENTF_EXTENDEDKEY = &H1
Const KEYEVENTF_KEYUP = &H2
Const KEYEVENTF_KEYDOWN = &H0
Sub KeyDown(KeyAscii)
keyCode = extern.MapVirtualKey(KeyAscii, 0)
'觸發按鍵按下事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYDOWN, 0
End Sub
Sub KeyUp(KeyAscii)
keyCode = extern.MapVirtualKey(KeyAscii, 0)
'觸發按鍵抬起事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYUP, 0
End Sub
Sub KeyPress(KeyAscii)
KeyDownKeyAscii
KeyUpKeyAscii
End Sub |
對“計算器”使用以上代碼
|
'聲明鍵值常量
Const vbKey1 = 49
Const vbKey2 = 50
ConstvbKeyAdd = 107
ConstvbKeyReturn = 13
SystemUtil.Run"calc.exe"
Window("title:=Calculator").Activate
Call KeyPress(vbKey1)
Call KeyPress(vbKeyAdd)
Call KeyPress(vbKey2)
Call KeyPress(vbKeyReturn) |
使用以上代碼模擬CTRL+ALT+S
|
'聲明鍵值常量
ConstvbKeyControl = 17
ConstvbKeyAlt = 18
ConstvbKeyS = 83
Call KeyDown(vbKeyControl)
Call KeyDown(vbKeyAlt)
Call KeyDown(vbKeyS)
Call KeyUp(vbKeyS)
Call KeyUp(vbKeyAlt)
Call KeyUp(vbKeyControl) |
問題 17-4.如何取到一個文本框的背景色 （當驗證必填項跟可選項底色不同時可用到）
|
'聲明需要的 API
Extern.Declare micLong,"GetPixel","gdi32","GetPixel",micLong,micLong,micLong
Extern.Declare micLong,"GetWindowDC","user32","GetWindowDC",micLong
Extern.Declare micLong,"ReleaseDC","user32","ReleaseDC",micLong,micLong
Extern.Declare micLong,"GetDC","user32","GetDC",micLong
Extern.Declare micLong,"SetForegroundWindow","user32","SetForegroundWindow",micLong
Dim hDCSource
Dim hWndSource
Dim backColor
'取得控件的句柄
hWndSource = Window("Window").WinEdit("MandatoryField1").GetROProperty("hwnd")
'將窗口置于最上面,因為GetPixel方法只能針對可見像素使用
extern.SetForegroundWindowhWndSource
'取得設備上下文句柄
hDCSource = Clng(Extern.GetDC(hWndSource))
'取得相關控件的像素(1,1)點的背景色
backColor = Clng(Extern.GetPixel(hDCSource, Clng(1),Clng(1)))
MsgBoxbackColor
'釋放設備上下文句柄
Extern.ReleaseDChWndSource, hDCSource |
問題 17-5.如何使用Windows API模擬鍵盤操作
|
'聲明API：鍵盤事件keybd_event
extern.Declare micVoid,"keybd_event","user32" ,"keybd_event", _
micbyte,micbyte,miclong,miclon
'聲明API：虛擬按鍵碼映射MapVirtualKey
extern.Declare micLong,"MapVirtualKey","user32","MapVirtualKeyA", _
micLong, micLong
Const KEYEVENTF_EXTENDEDKEY = &H1
Const KEYEVENTF_KEYUP = &H2
Const KEYEVENTF_KEYDOWN = &H0
Sub KeyDown(KeyAscii)
keyCode = extern.MapVirtualKey(KeyAscii, 0)
'觸發按鍵按下事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYDOWN, 0
End Sub
Sub KeyUp(KeyAscii)
keyCode = extern.MapVirtualKey(KeyAscii, 0)
'觸發按鍵抬起事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYUP, 0
End Sub
Sub KeyPress(KeyAscii)
KeyDownKeyAscii
KeyUpKeyAscii
End Sub |
對“計算器”使用以上代碼
|
'聲明鍵值常量
Const vbKey1 = 49
Const vbKey2 = 50
ConstvbKeyAdd = 107
ConstvbKeyReturn = 13
SystemUtil.Run"calc.exe"
Window("title:=Calculator").Activate
Call KeyPress(vbKey1)
Call KeyPress(vbKeyAdd)
Call KeyPress(vbKey2)
Call KeyPress(vbKeyReturn) |
使用以上代碼模擬CTRL+ALT+S
|
'聲明鍵值常量
ConstvbKeyControl = 17
ConstvbKeyAlt = 18
ConstvbKeyS = 83
Call KeyDown(vbKeyControl)
Call KeyDown(vbKeyAlt)
Call KeyDown(vbKeyS)
Call KeyUp(vbKeyS)
Call KeyUp(vbKeyAlt)
Call KeyUp(vbKeyControl) |