QTP自动化测试权威指南 连载(五)

QTP自动化测试权威指南 连载(五)

  微软Windows应用编程接口(API)为开发Windows应用程序提供了很多构建好的模块。它提供各种操作方法,比如获取鼠标坐标,窗口句柄,颜色等。QTP支持调用动态链接库内定义的这些方法,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的更多细节和信息可以从MSDN或者Visual Studio的API Viewer工具查询获得。

  Extern对象

  QTP提供一个Extern功能对象用来声明和调用API。

  语法

Extern.Declare (RetType, MethodName, LibName, Alias [, ArgType(s)])

  更多细节可参考QTP用户手册。

  VB API定义语法

Private Declare Function GetForegroundWindow Lib "user32.dll" () As Long

  对以上API,我们需要使用QTP的Declare方法确定使用的合适参数:

  RetType = micLong(函数返回类型)

  MethodName = "GetForegroudWindow" (我们可以使用任何其他名字,但是比较好的做法是使用实际API的名字)

  LibName = "user32.dll" (如果不是使用Windows系统自带的DLL,那么文件名必须使用绝对路径,例如"C:\MyApp\Lib\mylib.dll")

  Alias = "" 或者"GetForegroudWindow"(如果MethodName跟Alias相同,则Alias可以为空值。

  ArgType(s) =  本例中不需要传入参数)。

  QTP API定义

Extern.Declare micLong,"GetForegroundWindow","user32.dll","GetForegroundWindow"

  以下用一些用例来演示使用API解决通常遇到的问题。

  问题 17-1.如何判断当前桌面最上面的为浏览器窗口

'声明GetForeGroundWindow API
extern.Declare micLong,"GetForegroundWindow","user32.dll","GetForegroundWindow"

'获取最前面窗口的句柄
hwnd = extern.GetForegroundWindow()

'判断是否有包含此句柄的浏览器窗口
isBrowser = Browser("hwnd:=" &hwnd).Exist()
 
If isBrowser then
Msgbox "The top most window is a browser"
End if

  问题 17-2.如何获得Windows的环境变量 (注意不是QTP环境变量)

'变量声明
Dim s_EnvValue

'声明 API "GetEnvironmentVariable"
Extern.Declare micLong,"GetEnvironmentVariable","kernel32.dll","GetEnvironmentVariableA", _
micString,micString+micByRef,micLong

'获取全局变量 "TEMP" 值
Extern.GetEnvironmentVariable "TEMP",s_EnvValue,255 '会得到临时目录路径
MsgBoxs_EnvValue

  问题 17-3.如何使用Windwos API选中Listbox里的选项(item)

' 声明API
Extern.Declare micLong,"SendMessage","user32.dll","SendMessageA",micLong,micLong,micLong,micLong

' 设置Listbox选项item的消息
Const LB_SETSEL = &H185

'方法:根据index选中复选框
Function CheckListBox(hwnd, index)
extern.SendMessagehwnd, LB_SETSEL, True, index
end function

'方法:根据index取消选中复选框
Function UnCheckListBox(hwnd, index)
extern.SendMessagehwnd, LB_SETSEL, False, index
end function

  问题 17-4.如何取到一个文本框的背景色 (当验证必填项跟可选项底色不同时可用到)

'声明需要的 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")

'将窗口置于最上面,因为GetPixel方法只能针对可见像素使用
extern.SetForegroundWindowhWndSource

'取得设备上下文句柄
hDCSource = Clng(Extern.GetDC(hWndSource))

'取得相关控件的像素(1,1)点的背景色
backColor = Clng(Extern.GetPixel(hDCSource, Clng(1),Clng(1)))
MsgBoxbackColor

'释放设备上下文句柄
Extern.ReleaseDChWndSource, hDCSource

  问题 17-5.如何使用Windows API模拟键盘操作

'声明API:键盘事件keybd_event
extern.Declare micVoid,"keybd_event","user32" ,"keybd_event", _
micbyte,micbyte,miclong,miclon
'声明API:虚拟按键码映射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)
  '触发按键按下事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYDOWN, 0
End Sub

Sub KeyUp(KeyAscii)
keyCode = extern.MapVirtualKey(KeyAscii, 0)
 '触发按键抬起事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYUP, 0
End Sub

Sub KeyPress(KeyAscii)
KeyDownKeyAscii
KeyUpKeyAscii
End Sub

  对“计算器”使用以上代码

'声明键值常量
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)

  使用以上代码模拟CTRL+ALT+S

'声明键值常量
ConstvbKeyControl = 17
ConstvbKeyAlt = 18
ConstvbKeyS = 83

Call KeyDown(vbKeyControl)
Call KeyDown(vbKeyAlt)
Call KeyDown(vbKeyS)
Call KeyUp(vbKeyS)
Call KeyUp(vbKeyAlt)
Call KeyUp(vbKeyControl)

  问题 17-4.如何取到一个文本框的背景色 (当验证必填项跟可选项底色不同时可用到)

'声明需要的 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")

'将窗口置于最上面,因为GetPixel方法只能针对可见像素使用
extern.SetForegroundWindowhWndSource

'取得设备上下文句柄
hDCSource = Clng(Extern.GetDC(hWndSource))

'取得相关控件的像素(1,1)点的背景色
backColor = Clng(Extern.GetPixel(hDCSource, Clng(1),Clng(1)))
MsgBoxbackColor

'释放设备上下文句柄
Extern.ReleaseDChWndSource, hDCSource

  问题 17-5.如何使用Windows API模拟键盘操作

'声明API:键盘事件keybd_event
extern.Declare micVoid,"keybd_event","user32" ,"keybd_event", _
micbyte,micbyte,miclong,miclon
'声明API:虚拟按键码映射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)
  '触发按键按下事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYDOWN, 0
End Sub

Sub KeyUp(KeyAscii)
keyCode = extern.MapVirtualKey(KeyAscii, 0)
 '触发按键抬起事件
extern.keybd_eventKeyAscii, keyCode, KEYEVENTF_KEYUP, 0
End Sub

Sub KeyPress(KeyAscii)
KeyDownKeyAscii
KeyUpKeyAscii
End Sub

  对“计算器”使用以上代码

'声明键值常量
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)

  使用以上代码模拟CTRL+ALT+S

'声明键值常量
ConstvbKeyControl = 17
ConstvbKeyAlt = 18
ConstvbKeyS = 83

Call KeyDown(vbKeyControl)
Call KeyDown(vbKeyAlt)
Call KeyDown(vbKeyS)
Call KeyUp(vbKeyS)
Call KeyUp(vbKeyAlt)
Call KeyUp(vbKeyControl)

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