RE: TZF - Drag and Drop

I found the following which allows me to create an inherited component 
from DBGrid.  It could probably be used with ttzgrid as well.  I was 
able to get drag and drop to work in about 30 minutes with it.  


http://community.borland.com/article/0%2C1410%2C16562%2C00.html


i-cable wrote:
> 
> Dear Randy:
> I thought someone would answer you. May be everyone is having some good
> time. My 7.51 does have the mousedown event so I don't know anything 
> about.
> If the mousedown event works then it will be much better. My version 
> doesn't
> have mousedown so I use a special way to activate the drage mode. I 
> think
> someone may have a better way but since they are busy so I tell you my
> method.
> 1. I use the CornerleftClick event to enable the dragmode. Please see 
> the
> first method below.
> 2. As an example, I use a Label to accept the Drop. So I put in the 
> Tabel1's
> DragOver event so it will show the DragCursor. Pleas see the second 
> method.
> 3. To complete the Drop we need to put codes in the DragDrop of Label1.  
> It
> is better to make sure the draging component is the expected component
> before accepting it. Please see Method 3.
> 4. The DragDrop function is bascially completed. But don't forget we 
> have
> enabled the Dragmode of TZGrid1 to dmAutomatic. This will create a 
> problem
> in the future that the cells of TZGrid1 components cannot be selected
> anymore because drag mode will be started instead of selecting the cell.
> Therefore we need method 4 to cancel out the Dragmode. That is all we 
> need
> for the Drag and Drop.
> 
> The operation will be like that. You select a cell then double click the
> left corner of the TZGrid and hold the mouse and drag on the second 
> click.
> The first click will enter the dragmode then the second mouse down will
> start the dragging. It works like a double click but actually not really 
> a
> double click.
> 
> There is also another method to start the dragmode which may be more 
> useful
> to you because you have the mousedown event. In the
> TZGrid1CornerLeftClick(method 1), we can use the BeginDrag function 
> instead
> of changing the Dragmode. I don't like this method because I don't have
> mouse down. I only have click events. In other words, it starts function
> after the mouse button is released. This is not the windows convention. 
> But
> if you can make your mouse down event to work then this is a better way 
> to
> go.
> 
> I hope I have made my explaination clean. Good luck.
> Abi
> 
> procedure TForm1.TzGrid1CornerLeftClick(Sender: TObject);
> begin  {use the left corner to enable drag}
>   tzgrid1.dragmode:=dmautomatic;
>  {tzgrid1.begindrag(false);  another method}
> end;
> 
> 
> procedure TForm1.Label1DragOver(Sender, Source: TObject; X, Y: Integer;
>   State: TDragState; var Accept: Boolean);
> begin  {To Show the dragcur}
>   accept:=true;
> end;
> 
> procedure TForm1.Label1DragDrop(Sender, Source: TObject; X, Y: Integer);
> begin  {the label will accept anything from the TZGRID}
>    if source is ttzgrid then begin
>      label1.caption:=(source as ttzgrid).fields[(source as
> ttzgrid).col-1].AsString;
>    end;
> end;
> 
> procedure TForm1.TzGrid1EndDrag(Sender, Target: TObject; X, Y: Integer);
> begin   {Must cancel out the drag mode otherwise we can't select a cell 
> any
> more}
>   tzgrid1.dragmode:=dmmanual;
> end;
> 
> 
> > Thanks for the response.  I am using v8.04 (I think) The control shows a
> > mousedown event, but it never gets called.  The dmautomatic drag
> > property causes problems with the ondblclick event because it happens
> > immediately.  Any thoughts?  Benno sent me some code to try as well.
> > Thanks again.
> > i-cable wrote:
> > >
> > > Dear Randy:
> > > I don't see a Mousedown event in TTzgrid. My version is 7.51. Not sure
> > > about
> > > higher version.
> > > May be you have set the Mousedown event of the Form instead. But when
> > > you
> > > click the mouse inside the TTzgrid component, the Form does get the
> > > click so
> > > the FORM.MouseDown event it is not triggered. If you want to use drag,
> > > you
> > > need to set DragMode to dmAutomatic then use the OnDragOver event.
> > >
> > > Hope this can help.
> > >
> > > Abi
> > >
> > >
> > > > I am trying to use drag and drop between dBF files using two
> > > > TTZDBGRID's.  I want to use the Mousedown event to start the drag
> > > > process, but it never gets called when I click the mouse down.  Can
> > > > someone help me understand why this wouldn't work.
> > > >
> > > > Thanks
> > > > Randy
> > > >
> > > >
> > >
> > >
> >
> >
> 
> 

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