Visual Basic 6 Black Book
(Publisher: The Coriolis Group)
Author(s): Steven Holzner
ISBN: 1576102831
Publication Date: 08/01/98

Chapter 11
Windows Common Dialogs

If you need an immediate solution to:

Creating And Displaying A Windows Common Dialog

Setting A Common Dialog’s Title

Did The User Click OK Or Cancel?

Using A Color Dialog Box

Setting Color Dialog Flags

Using The Open And Save As Dialogs

Setting Open And Save As Flags

Getting The File Name In Open, Save As Dialogs

Setting Maximum File Name Size In Open And Save As Dialog Boxes

Setting Default File Extensions

Set Or Get The Initial Directory

Setting File Types (Filters) In Open, Save As Dialogs

Using A Font Dialog Box

Setting Font Dialog Flags

Setting Max And Min Font Sizes

Using The Print Dialog Box

Setting Print Dialog Flags

Setting The Minimum And Maximum Pages To Print

Setting Page Orientation

Showing Windows Help From A Visual Basic Program

In Depth

In this chapter, we’re going to examine the Windows Common Dialogs, which provide a powerful and professional set of dialog boxes for interacting with the user. Microsoft created the Common Dialogs to promote a common user interface across all Windows programs, and in fact the Common Dialogs do work well—and they make programming easier for the programmer. Having a common user interface across all Windows programs is valuable for the user, because it simplifies tasks. For the programmer, the Common Dialogs means that we have a powerful set of dialog boxes ready for us to use, without having to create them ourselves. From both ends of the spectrum, then, the Windows Common Dialogs may be considered a success.

The Common Dialog control can display five different dialog boxes—Open A File, Save A File, Set A Color, Set A Font, and Print A Document.

The Common Dialog Control

The Common Dialogs are all part of one control: the Common Dialog control. You add that control to a program with the Visual Basic Project|Components menu item. Click the Controls tab in the Components box that opens, and select the entry labeled Microsoft Common Dialog Control, then click on OK to close the Components box. You add a Common Dialog control to a form in the usual way—just double-click the Common Dialog tool in the toolbox, or select it and paint the control on the form. The Common Dialog tool appears as the eleventh tool down on the right in the Visual Basic toolbox in Figure 11.1. The Common Dialog control will appear as a nonresizable icon on your form and is not visible at runtime.

Figure 11.1  The Common Dialog tool.

You use the control’s Action property to display a dialog box or, equivalently, these methods:

•  ShowOpen—Show Open dialog box

•  ShowSave—Show Save As dialog box

•  ShowColor—Show Color dialog box

•  ShowFont—Show Font dialog box

•  ShowPrinter—Show Print or Print Options dialog box

Besides these dialog boxes, you can also display Windows Help:

•  ShowHelp—Invokes the Windows Help engine

The Common Dialog control automatically provides context-sensitive Help on the interface of the dialog boxes. You invoke context-sensitive Help by clicking the Help button labeled What’s This in the title bar, then clicking the item for which you want more information. In addition, you can right-click the item for which you want more information, then select the What’s This command in the displayed context menu.

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TIP:  We might also note, by the way, that there is no way currently to specify where a dialog box is displayed; that might change in some future release.

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As an example, the Font dialog box appears in Figure 11.2.

Figure 11.2  The Font dialog box.

That’s really all the overview we need. We’re ready to start the Immediate Solutions now.

Immediate Solutions

Creating And Displaying A Windows Common Dialog

The Testing Department is calling again. Your program, SuperDuperTextPro, is great, but why is the File Save As dialog box the size of a postage stamp? And why is it colored purple? Shouldn’t it match the uniform kind of dialog box that other Windows programs use?

To make your dialog boxes look just like the dialog boxes other programs use (and add professionalism to your program), you can use the Windows Common Dialogs, which are wrapped up in the Windows Common Dialog control. The Common Dialog control can display five different dialog boxes—Open A File, Save A File, Set A Color, Set A Font, and Print A Document, and you can also display Windows Help.

Adding a Windows Common Dialog control to your program is easy: just follow these steps:

1.  Select the Project|Components menu item.

2.  Select the Controls tab in the Components box that opens.

3.  Select the entry labeled Microsoft Common Dialog Control, then click on OK to close the Components box.

4.  Add a Common Dialog control to a form in the usual way—just double-click the Common Dialog tool in the toolbox, or select it and paint the control on the form. (The Common Dialog tool appears as the eleventh tool down on the right in the Visual Basic toolbox in Figure 11.1.)

5.  Add the code you want to open the dialog box and make use of values the user sets.

To display various dialog boxes, you use these Common Dialog methods (for example, CommonDialog1.ShowColor):

•  ShowOpen—Show Open dialog box

•  ShowSave—Show Save As dialog box

•  ShowColor—Show Color dialog box

•  ShowFont—Show Font dialog box

•  ShowPrinter—Show Print or Print Options dialog box

•  ShowHelp—Invokes the Windows Help engine

You can also set the Common Dialog’s Action property to do the same thing (and in fact, that’s the way you used to display Common Dialogs until recent Visual Basic releases). Microsoft says that using the preceding methods “adds functionality,” but in fact, the two ways of displaying dialog boxes are equivalent at this writing (although using methods like ShowHelp instead of Action = 6 makes code a little clearer). Here are the values you can place in the Action property:

•  0—No action

•  1—Displays the Open dialog box

•  2—Displays the Save As dialog box

•  3—Displays the Color dialog box

•  4—Displays the Font dialog box

•  5—Displays the Print dialog box

•  6—Runs winhelp32.exe