How to make the TScollBox automatically scroll when DragMode is dmAutomatic?











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I have a ScrollBox in which I have a GridPanel in which I have Buttons.
I set DragMode to dmAutomatic for all buttons so I can move the buttons around (drag and drop).



But I have a problem: because the GridPanel is larger than the ScrollBox, the ScrollBox has the vertical scrollbar visible. I want to make the ScrollBar to automatically scroll down so I can drop a bottom from the visible (top) rows into the inaccessible rows at the bottom (this is typical behavior for all Windows programs, right?)



I have simple code that is doing this: In MouseMove I detect when the mouse is getting close to the bottom of the ScrollBox and I adjust ScrollBox.VertScrollBa.Position to scroll down. This works ONLY if I am NOT in "drag and drop" mode (if I am not dragging a button).



If I start a drag and drop operation NO mouse events are fired.



What can I do to receive MouseMove event even if I am in "drag and drop" mode?

A solution would be not to use dmAutomatic and implement my own drag and drop alternative (based on mousedown, mousemove, mouseup). Is these a quicker fix?










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  • 1




    If I remember correctly a TDragObject will receive and handle the mouse messages during Drag&Drop. But you should then get e.g. DragOver events instead.
    – nil
    Nov 22 at 16:14










  • @nil - I think I get the idea: "move the code from MouseMove to DragOver". I will try it. thanks!
    – Rigel
    Nov 22 at 16:15












  • Maybe, if it's true that you receive MouseMove when not dragging and DragOver when dragging.
    – nil
    Nov 22 at 16:19










  • @nil - it works. can you post your comment as an answer so I can accept it? 1.5 million thanks.
    – Rigel
    Nov 22 at 16:25








  • 1




    "What can I do to receive MouseMove event even if I am in "drag and drop" mode?" - Nothing... you can't. See documentation for SetCapture on MSDN for explanation. Called from TDragObject.Capture.
    – Sertac Akyuz
    Nov 22 at 16:39















up vote
1
down vote

favorite












I have a ScrollBox in which I have a GridPanel in which I have Buttons.
I set DragMode to dmAutomatic for all buttons so I can move the buttons around (drag and drop).



But I have a problem: because the GridPanel is larger than the ScrollBox, the ScrollBox has the vertical scrollbar visible. I want to make the ScrollBar to automatically scroll down so I can drop a bottom from the visible (top) rows into the inaccessible rows at the bottom (this is typical behavior for all Windows programs, right?)



I have simple code that is doing this: In MouseMove I detect when the mouse is getting close to the bottom of the ScrollBox and I adjust ScrollBox.VertScrollBa.Position to scroll down. This works ONLY if I am NOT in "drag and drop" mode (if I am not dragging a button).



If I start a drag and drop operation NO mouse events are fired.



What can I do to receive MouseMove event even if I am in "drag and drop" mode?

A solution would be not to use dmAutomatic and implement my own drag and drop alternative (based on mousedown, mousemove, mouseup). Is these a quicker fix?










share|improve this question




















  • 1




    If I remember correctly a TDragObject will receive and handle the mouse messages during Drag&Drop. But you should then get e.g. DragOver events instead.
    – nil
    Nov 22 at 16:14










  • @nil - I think I get the idea: "move the code from MouseMove to DragOver". I will try it. thanks!
    – Rigel
    Nov 22 at 16:15












  • Maybe, if it's true that you receive MouseMove when not dragging and DragOver when dragging.
    – nil
    Nov 22 at 16:19










  • @nil - it works. can you post your comment as an answer so I can accept it? 1.5 million thanks.
    – Rigel
    Nov 22 at 16:25








  • 1




    "What can I do to receive MouseMove event even if I am in "drag and drop" mode?" - Nothing... you can't. See documentation for SetCapture on MSDN for explanation. Called from TDragObject.Capture.
    – Sertac Akyuz
    Nov 22 at 16:39













up vote
1
down vote

favorite









up vote
1
down vote

favorite











I have a ScrollBox in which I have a GridPanel in which I have Buttons.
I set DragMode to dmAutomatic for all buttons so I can move the buttons around (drag and drop).



But I have a problem: because the GridPanel is larger than the ScrollBox, the ScrollBox has the vertical scrollbar visible. I want to make the ScrollBar to automatically scroll down so I can drop a bottom from the visible (top) rows into the inaccessible rows at the bottom (this is typical behavior for all Windows programs, right?)



I have simple code that is doing this: In MouseMove I detect when the mouse is getting close to the bottom of the ScrollBox and I adjust ScrollBox.VertScrollBa.Position to scroll down. This works ONLY if I am NOT in "drag and drop" mode (if I am not dragging a button).



If I start a drag and drop operation NO mouse events are fired.



What can I do to receive MouseMove event even if I am in "drag and drop" mode?

A solution would be not to use dmAutomatic and implement my own drag and drop alternative (based on mousedown, mousemove, mouseup). Is these a quicker fix?










share|improve this question















I have a ScrollBox in which I have a GridPanel in which I have Buttons.
I set DragMode to dmAutomatic for all buttons so I can move the buttons around (drag and drop).



But I have a problem: because the GridPanel is larger than the ScrollBox, the ScrollBox has the vertical scrollbar visible. I want to make the ScrollBar to automatically scroll down so I can drop a bottom from the visible (top) rows into the inaccessible rows at the bottom (this is typical behavior for all Windows programs, right?)



I have simple code that is doing this: In MouseMove I detect when the mouse is getting close to the bottom of the ScrollBox and I adjust ScrollBox.VertScrollBa.Position to scroll down. This works ONLY if I am NOT in "drag and drop" mode (if I am not dragging a button).



If I start a drag and drop operation NO mouse events are fired.



What can I do to receive MouseMove event even if I am in "drag and drop" mode?

A solution would be not to use dmAutomatic and implement my own drag and drop alternative (based on mousedown, mousemove, mouseup). Is these a quicker fix?







delphi mouseevent c++builder onmouseover






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edited Nov 22 at 16:13

























asked Nov 22 at 16:02









Rigel

9,91014110218




9,91014110218








  • 1




    If I remember correctly a TDragObject will receive and handle the mouse messages during Drag&Drop. But you should then get e.g. DragOver events instead.
    – nil
    Nov 22 at 16:14










  • @nil - I think I get the idea: "move the code from MouseMove to DragOver". I will try it. thanks!
    – Rigel
    Nov 22 at 16:15












  • Maybe, if it's true that you receive MouseMove when not dragging and DragOver when dragging.
    – nil
    Nov 22 at 16:19










  • @nil - it works. can you post your comment as an answer so I can accept it? 1.5 million thanks.
    – Rigel
    Nov 22 at 16:25








  • 1




    "What can I do to receive MouseMove event even if I am in "drag and drop" mode?" - Nothing... you can't. See documentation for SetCapture on MSDN for explanation. Called from TDragObject.Capture.
    – Sertac Akyuz
    Nov 22 at 16:39














  • 1




    If I remember correctly a TDragObject will receive and handle the mouse messages during Drag&Drop. But you should then get e.g. DragOver events instead.
    – nil
    Nov 22 at 16:14










  • @nil - I think I get the idea: "move the code from MouseMove to DragOver". I will try it. thanks!
    – Rigel
    Nov 22 at 16:15












  • Maybe, if it's true that you receive MouseMove when not dragging and DragOver when dragging.
    – nil
    Nov 22 at 16:19










  • @nil - it works. can you post your comment as an answer so I can accept it? 1.5 million thanks.
    – Rigel
    Nov 22 at 16:25








  • 1




    "What can I do to receive MouseMove event even if I am in "drag and drop" mode?" - Nothing... you can't. See documentation for SetCapture on MSDN for explanation. Called from TDragObject.Capture.
    – Sertac Akyuz
    Nov 22 at 16:39








1




1




If I remember correctly a TDragObject will receive and handle the mouse messages during Drag&Drop. But you should then get e.g. DragOver events instead.
– nil
Nov 22 at 16:14




If I remember correctly a TDragObject will receive and handle the mouse messages during Drag&Drop. But you should then get e.g. DragOver events instead.
– nil
Nov 22 at 16:14












@nil - I think I get the idea: "move the code from MouseMove to DragOver". I will try it. thanks!
– Rigel
Nov 22 at 16:15






@nil - I think I get the idea: "move the code from MouseMove to DragOver". I will try it. thanks!
– Rigel
Nov 22 at 16:15














Maybe, if it's true that you receive MouseMove when not dragging and DragOver when dragging.
– nil
Nov 22 at 16:19




Maybe, if it's true that you receive MouseMove when not dragging and DragOver when dragging.
– nil
Nov 22 at 16:19












@nil - it works. can you post your comment as an answer so I can accept it? 1.5 million thanks.
– Rigel
Nov 22 at 16:25






@nil - it works. can you post your comment as an answer so I can accept it? 1.5 million thanks.
– Rigel
Nov 22 at 16:25






1




1




"What can I do to receive MouseMove event even if I am in "drag and drop" mode?" - Nothing... you can't. See documentation for SetCapture on MSDN for explanation. Called from TDragObject.Capture.
– Sertac Akyuz
Nov 22 at 16:39




"What can I do to receive MouseMove event even if I am in "drag and drop" mode?" - Nothing... you can't. See documentation for SetCapture on MSDN for explanation. Called from TDragObject.Capture.
– Sertac Akyuz
Nov 22 at 16:39












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During drag-and-drop operations the VCL will create a TDragObject to manage said drag-and-drop operation. This TDragObject - or a derived class - will start receiving and handling mouse events as long as dragging lasts. In turn, it will generate drag-and-drop specific events like OnDragOver and OnDragDrop which can be handled by - potential target - controls under current mouse position.



This will allow you to handle OnMouseMove whenever no drag-and-drop is happening. In addition handle OnDragOver in a similar way to catch mouse movements when currently dragging.






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    During drag-and-drop operations the VCL will create a TDragObject to manage said drag-and-drop operation. This TDragObject - or a derived class - will start receiving and handling mouse events as long as dragging lasts. In turn, it will generate drag-and-drop specific events like OnDragOver and OnDragDrop which can be handled by - potential target - controls under current mouse position.



    This will allow you to handle OnMouseMove whenever no drag-and-drop is happening. In addition handle OnDragOver in a similar way to catch mouse movements when currently dragging.






    share|improve this answer



























      up vote
      4
      down vote



      accepted










      During drag-and-drop operations the VCL will create a TDragObject to manage said drag-and-drop operation. This TDragObject - or a derived class - will start receiving and handling mouse events as long as dragging lasts. In turn, it will generate drag-and-drop specific events like OnDragOver and OnDragDrop which can be handled by - potential target - controls under current mouse position.



      This will allow you to handle OnMouseMove whenever no drag-and-drop is happening. In addition handle OnDragOver in a similar way to catch mouse movements when currently dragging.






      share|improve this answer

























        up vote
        4
        down vote



        accepted







        up vote
        4
        down vote



        accepted






        During drag-and-drop operations the VCL will create a TDragObject to manage said drag-and-drop operation. This TDragObject - or a derived class - will start receiving and handling mouse events as long as dragging lasts. In turn, it will generate drag-and-drop specific events like OnDragOver and OnDragDrop which can be handled by - potential target - controls under current mouse position.



        This will allow you to handle OnMouseMove whenever no drag-and-drop is happening. In addition handle OnDragOver in a similar way to catch mouse movements when currently dragging.






        share|improve this answer














        During drag-and-drop operations the VCL will create a TDragObject to manage said drag-and-drop operation. This TDragObject - or a derived class - will start receiving and handling mouse events as long as dragging lasts. In turn, it will generate drag-and-drop specific events like OnDragOver and OnDragDrop which can be handled by - potential target - controls under current mouse position.



        This will allow you to handle OnMouseMove whenever no drag-and-drop is happening. In addition handle OnDragOver in a similar way to catch mouse movements when currently dragging.







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Nov 22 at 16:55

























        answered Nov 22 at 16:44









        nil

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        1,1161318






























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