November 1st, 2023
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More notes on use of the DS_CONTROL style

Raymond Chen
Raymond Chen

Here’s a follow-up on some old articles on the DS_CONTROL dialog style and avoiding accidental control ID collisions.

When you add the DS_CONTROL style to your dialog template, there are other changes to the dialog styles which come into play. Some are mandatory, some are automatic, and some are optional.

Mandatory: You must remove the WS_POPUP style and you must add the WS_CHILD style. If you omit the WS_CHILD style or accidentally specify the WS_POPUP style, then the dialog won’t be created as a child window of the parent window you specified.

Automatic: You may remove the WS_CAPTION and WS_SYS­MENU styles. The dialog manager removes them automatically, so this isn’t a requirement, but you are welcome to remove them yourself, either to avoid confusion or out of a sense of cleanliness.

Optional: You have the option of adding or removing the WS_VISIBLE and DS_MODAL­FRAME styles, depending on the behavior you desire.

If you specify WS_VISIBLE, then the child dialog will be created visible. Otherwise, it will be created hidden.

If you specify DS_MODAL­FRAME, then the child dialog gets the WS_EX_WINDOW­EDGE extended style, which gives it an extra outer edge border. If you want the child dialog to blend in seamlessly with its parent, then you probably want to remove that style.

Category
Old New Thing
Topics
Code

Author

Raymond Chen

Raymond has been involved in the evolution of Windows for more than 30 years. In 2003, he began a Web site known as The Old New Thing which has grown in popularity far beyond his wildest imagination, a development which still gives him the heebie-jeebies. The Web site spawned a book, coincidentally also titled The Old New Thing (Addison Wesley 2007). He occasionally appears on the Windows Dev Docs Twitter account to tell stories which convey no useful information.

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  • Jonathan Wilson

    If removing WS_POPUP and adding WS_CHILD is mandatory, why doesn’t the dialog manager do it for you similar to how it removes WS_CAPTION and WS_SYSMENU?

    • Raymond ChenMicrosoft employee Author

      It’s not mandatory in the sense that “if you don’t do it, the operation fails”. It is technically legal to leave those flags in place, but the results are almost certainly not what you want.

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