SAMPLE: Code Demonstrates Flashing an Edit Control

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.0 and 3.1

SUMMARY

If an application window or dialog box has a number of edit controls, the user can lose track of the control that has the input focus. FLSHEDIT is a file in the Microsoft Software Library that demonstrates how to make an edit control flash to indicate that the control has the input focus. The technique used by FLSHEDIT is similar to calling the FlashWindow function. FlashWindow flashes the caption bar on a window to gain the user's attention.

Download FLSHEDIT.EXE, a self-extracting file, from the Microsoft Software Library (MSL) on the following services:

• Microsoft Download Service (MSDL)

        Dial (206) 936-6735 to connect to MSDL
        Download FLSHEDIT.EXE (size: 30447 bytes) 
  

• Internet (anonymous FTP)

        ftp ftp.microsoft.com
        Change to the \SOFTLIB\MSLFILES directory
        Get FLSHEDIT.EXE (size: 30447 bytes) 
  

MORE INFORMATION

The FLSHEDIT sample contains a dialog box with four edit controls. The application uses one timer, which is used to flash whichever edit control has the focus. The application sets the timer each time an edit control receives the input focus (an EN_SETFOCUS message). The timer is destroyed when an edit control loses the input focus (an EN_KILLFOCUS message) or when the context of the edit control changes (an EN_CHANGE message).

When the specified time elapses and the application receives a WM_TIMER message, the application invalidates the contents of the edit control and specifies the new text and background colors. Then Windows redraws the control using the new colors.

Therefore, a control stops flashing when either of the following events take place:

• The user takes the input focus away from the control.
• The user changes the text contents of the control.

In addition to flashing, the FLSHEDIT sample changes the text in an edit control to indicate that the control has the input focus. However, if the user changes the contents of an edit control, the changed text remains even after the user moves the input focus to another control. If the user changes the text to an empty string, the edit control regains its default contents.

Windows 3.0 does not properly change the background color of a single-line edit control.

FLSHEDIT incorporates the first method provided by this Knowledge Base article.