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After setting ListView in virtual mode ListView1.Selected.Top always returns 0. I'm using that property on double click on list view to show edit box at that position.

How can I resolve this?

Example of .pas and .dfm files are here. I want to open edit box on position where it is double clicked.

I need to call batch script from Delphi. I'm using TDosCommand because I want to show echo messages from batch before external process finishes. How to wait in procedure until script finishes?

Here is simple demo example. I'm calling Test.bat on click. Pause is only for testing purpose.

Test.bat.

Update:

Indeed, the issue was fixed since 10.2. I compared the FMX.Platform.Win from 10.4, the fix is in the function TWinDropTarget.GetDataObject: TDragObject;

I've implemented the answer for Drag and drop with TTreeView in Firemonkey to drag&drop TTreeViewItems in a Delphi 10.2 FMX Windows application.

Everything is working perfectly within the same app, however when the user suddenly drops an item to another copy of the same app, it hangs or even shuts down with c0000374 external error.

When trying to debug in the IDE, the source app stops with this system call stack:

I don't actually need the ability to drag between applications (although, it would be perfect). I'm just asking, how to avoid such errors?

According to the comment below, I've added a minimal example. Create a Win32 FMX app and add a TLabel to it:

I'm using Delphi XE7 on Windows 10.

I have been using the following code for a long time, and just read the documentation on SetTimer(). To state it simply, I am setting timers from non-UI threads, but Microsoft's documentation says they should only be set on the UI thread. Extensive tests show my code works fine, but I can't trust my system to behave the same as other systems, or the Microsoft documentation to be 100% accurate. Can anyone verify whether this code is OK or not OK?

The Delphi code will not deadlock, it pretty much just calls SetTimer() (I am aware there is a race condition setting TTimer.FEnabled).

The MSDN documentation says:

hWnd

Type: HWND

A handle to the window to be associated with the timer. This window must be owned by the calling thread.

What I'm trying to accomplish is worker threads doing stuff, and when appropriate, they notify the main thread that elements of the UI must be updated, and the main thread updates the UI. I know how to use TThread.Synchronize(), but deadlocks can happen in certain cases. I can use PostMessage() from my worker threads and handle the message in the UI thread.

Is there any other way in Delphi to notify and update the UI thread?

I would like to have my stack trace contain unit names / methods / lines. Anything that can help really to make it more readable. I know this has worked in the past, but it has stopped working...

I have enabled

I want to implement an interface, but I cannot declare it from TInterfacedObject, and in this case the documentation says that I must implement QueryInterface, _AddRef, _Release. But I am not sure if this is mandatory. I haven't really worked with interfaces so far... They say something about COM objects, but I don't even know what that means. I never intentionally used COM objects, maybe only if they are included in some pieces of code which I took from the internet. I tried an example (see below) and it's working without implementing those 3 methods. So...

1. How should I know if I must implemet them ?
2. If I must implement them, how can I do it ? I don't know nothing about those methods should do. Should I copy the implementation from TInterfacedObject ? (In fact, it has more than 3... those extra ones must be copied too ?)

Thanks !

I try to change the field name of FDMemTable1field1 which is 'field1' to 'field3'. There is no code and all is done in design-time.

I have to prepare an individual unit to communicate with another system by TCP/IP.

I created two units: Unit1 with a TForm, and Unit2 with communications.

Unit1:

I updated my code and looked over it. The problem is when I try to generate NextButton4 and NextButton3 with procedure TForm2.Next1Click(Sender:TObject) in AForm(which is my Form that is created by TForm2.Button1Click) it won`t work like i can not see NextButton4 and NextButton3 in AForm. Delphi tells me that it is possible that AForm could not be intialized in line 117 (which says NextButton3 := TButton.Create(AForm);) but i do not know how to fix it. Sorry that I did not explain it very well. (the clickable component for TForm2.Next1Click(Sender:TObject); is NextButton1). My aim is to create a working ToDoList. For that I need a Mainform where Button1 is located. Button1 when clicked now creates lists/folders (AButton) on the Mainform(Form2) and a new form(AForm) where is now located NextButton1 and NextButton2. Now I want to store memories, task,... in AForm thats why i need two more Buttons (NextButton3 and NextButton4). NextButton2 should just close the form (AForm). And NextButton1 should, if clicked, create 2 Buttons (NextButton3 and NextButton4) and another form(NextForm). At the End I want to add one panel in AForm to store memories and tasks(did not add the panel yet). NextButton4 should open NextForm. In NextForm you can edit the Panel i did not create yet (f.e. change colour or name of the memory/task). The Problem with this is that NextButton3 and NextButton4 is created(I think) but i can not see it. Hope you can understand what I wrote.