SAMPLE: EdAlign.exe Changes Text Alignment in Edit Control

ID: Q66942

The information in this article applies to:

SUMMARY

A Microsoft Windows edit control aligns its contents to the left or right margins, or centers its contents, depending on the window style of the control. The control styles ES_LEFT, ES_CENTER, and ES_RIGHT specify left, center, and right-alignment, respectively.

There is a sample application named EDALIGN in the Microsoft Software Library that demonstrates each of these methods. Note, however, that this sample is a Windows 3.1 sample only.


MORE INFORMATION

The following file is available for download from the Microsoft Software Library:

~ EdAlign.exe
For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:
Q119591 : How to Obtain Microsoft Support Files from Online Services


Only multiline edit controls can be right-aligned or centered. Single-line edit controls are always left-aligned, regardless of the control style given.

Windows does not support altering the alignment style of a multiline edit control after it has been created. However, there are two methods that you can use to cause a multiline edit control in a dialog box to appear to change alignment. Note that in each of these methods, the dialog box that contains the control must be created with the DS_LOCALEDIT style.

The first method applies to all platforms. The second method does not apply to Windows 95 and Windows 98. Under Windows 95 and 98, EM_SETHANDlE and EM_GETHANDLE are not supported. For more information, please see the following articles in the Microsoft Knowledge Base:
Q130759 : EM_SETHANDLE and EM_GETHANDLE Messages Not Supported

Method 1

Create three controls: one left-aligned, one centered, and one right- aligned. Each has the same dimensions and position in the dialog box, but only one is initially made visible.

When the alignment is to change, call ShowWindow() to hide the visible control and to make one of the other controls visible.

To keep the text identical in all three controls, use the EM_GETHANDLE and EM_SETHANDLE messages to share the same memory among all three controls.

Method 2

Initially create a single control. When the text alignment is to change, retrieve location, size, and style bits for the existing edit control. Create a new control with the same size and in the same location, but change the style bits to reflect the new alignment.

Send the EM_GETHANDLE to each control to retrieve a handle to the memory that stores the contents. Send an EM_SETHANDLE to each control to exchange the memory used by each. Finally, destroy the original control. 


Keywords          : kbfile kbsample kbCtrl kbEditCtrl kbNTOS kbNTOS350 kbNTOS351 kbSDKWin32 kbGrpUser kbWinOS kbWinOS95 
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Last Reviewed: March 6, 1999