Tag Property

[Anonymous]

One thing I miss a lot from my VB development projects is a tag value for controls on a form, so I guess it would be nice to add this if it were possible.

One place I use tags (string values) is to record information about checkboxes. So if I've got a dozen checkboxes on a form I would use the tag to record a value identifying that particular control. This was particularly useful when recording values in an INI file - you could set the tag to be the key name in the INI file and then iterate thru the controls without having to remember the values.

I appreciate it is possible to use the index number of the control to do this, but a tag property would round this out nicely. There's also the issue of sometimes moving checkboxes around on a form to change the order, and the index sequence might be updated.

Andrew

[TechSupport]

You can also use the SetProp and GetProp API functions to store a 32-bit value with the control's window handle (i.e. the HWND_ variable).

I believe that the Tag request has come up before. I'll add it to "the list" again.

[Anonymous]

Paul

Please give me an example how it works SetProp and GetProp?

Thanks
Stephane

[Roger Garstang]

Paul uses it as a neat way to store control/form information in the generated code:

ff = HeapAlloc(GetProcessHeap(), %HEAP_ZERO_MEMORY, SIZEOF(@ff)) 'Allocate Memory for FF_DATA Structure
IF ff THEN SetProp hWndControl, "FF_PTR", ff  'Store the pointer for later use

Then when he wants to get data from the structure for a certain control:

ff = GetProp(hWndControl, "FF_PTR") ' Get Value of FF_PTR structure pointer that we stored

The "FF_PTR" in the Prop calls is the Name of the value to retrieve from the control, not to be confused with the actual FF_PTR structure that the handle it stores/returns is pointing to.

Think of it as the Dialog Get User and Dialog Set User in PB's DDT...only better.

Note: The documentation says you need to remove the properties you added when the control/form is destroyed (WM_DESTROY), so for this example use: RemoveProp hWndControl, "FF_PTR"

You'd also need to free allocated memory with HeapFree(GetProcessHeap(), 0, BYVAL ff).