Insider Power Techniques for Microsoft Windows XP [Electronic resources] نسخه متنی

Displaying More Detailed Information to the User

You saw earlier that the WScript object’s Echo method is useful for displaying simple text messages to the user. You can gain more control over the displayed message by using the WshShell object’s Popup method. WshShell refers to the Shell object that is exposed via the Automation interface of WScript. So before you can run the Popup method, you need to use CreateObject to create an instance of the WshShell object:

Set objWshShell = WScript.CreateObject(“WScript.Shell”)

If you’re familiar with Microsoft Visual Basic, the Popup method is similar to the MsgBox function in that it enables you to control both the dialog box title and the buttons that are displayed, as well as to determine which of those buttons the user pressed. Here’s the syntax:

Popup strText, [nSecondsToWait], [strTitle], [nType]

strText

nSecondsToWait

strTitle

nType

For example, the following statements display the dialog box shown in Figure 3-1:

Set objWshShell = WScript.CreateObject(“WScript.Shell”)
objWshShell.Popup “Couldn’t find MEMO.DOC!", , “Warning”

Figure 3-1: This is a simple message dialog box produced by the Popup method.

objWshShell.Popup "First line" & vbCrLf & "Second line"

Setting the Style of the Message

The default Popup dialog box displays only an OK button. You can include other buttons and icons in the dialog box by using different values for the nType parameter. Table 3-1 lists the available options.

You derive the nType argument in one of two ways:

By adding up the values for each option.

By using the VBScript constants separated by plus signs (+).

The script below shows an example:

‘ First, set up the message  strText = “Are you sure you want to copy” & vbCrLf & _
“the selected files to drive A?"  strTitle = “Copy Files"  nType = vbYesNoCancel + vbQuestion + vbDefaultButton2    ‘ Now display it  Set objWshShell = WScript.CreateObject(“WScript.Shell”)
intResult = objWshShell.Popup(strText, ,strTitle, nType)

Figure 3-2 shows the resulting dialog box. Here, three variables—strText, strTitle, and nType—store the values for the Popup method’s arguments. In particular, the following statement derives the nType argument:

Figure 3-2: This is the dialog box that’s displayed when you run the script.

nType = vbYesNoCancel + vbQuestion + vbDefaultButton2

You also could derive the nType argument by adding up the values that these constants represent (3, 32, and 256, respectively), but the script becomes less readable that way.

Getting Return Values from the Message Dialog Box

A dialog box that displays only an OK button is straightforward. The user either clicks OK or presses Enter to remove the dialog from the screen. The multibutton styles are a little different, however; the user has a choice of buttons to select, and your script needs a way to find out which button the user chose.

You do this by storing the Popup method’s return value in a variable. Table 3-2 lists the seven possible return values.

To process the return value, you can use an If...Then...Else or Select Case structure to test for the appropriate values. For example, the script shown earlier used a variable called intResult to store the return value of the Popup method. The following script shows a revised version of the script that uses a VBScript Select Case statement to test for the three possible return values, based on using vbYesNoCancel.

 ‘ First, set up the message
strText = “Are you sure you want to copy” & vbCrLf & _
“the selected files to drive A?"
strTitle = “Copy Files"
nType = vbYesNoCancel + vbQuestion + vbDefaultButton2
‘ Now display it
Set objWshShell = WScript.CreateObject(“WScript.Shell”)
intResult = objWshShell.Popup(strText, ,strTitle, nType)
‘ Process the result
Select Case intResult
Case vbYes
WScript.Echo “You clicked “"Yes"“!"
Case vbNo
WScript.Echo “You clicked “"No"“!"
Case vbCancel
WScript.Echo “You clicked “"Cancel"“!"
End Select