DragDrop Files from explorer to ListView

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3 total messages Started by Maarten Veerman Sat, 11 Jan 2003 11:09

#936

Author: Maarten Veerman
Date: Sat, 11 Jan 2003 11:09

67 lines
3080 bytes

Hi,

I have a problem with dropping files in a ListView. I use the code that
everybody can find in the Delphipages TIPS section:
http://www.delphipages.com/tips/thread.cfm?ID=95&SR=drag
(See below for code)

Anyway, I try setting the DragAcceptFiles like this:
DragAcceptFiles(ListView1.Handle,True);

When I drag files over the listview it seems like it will accept the files,
since the cursor changes. But when I drop the files, the TForm1.WMDROPFILES
procedure is not activated, so nothing is dropped.

Strangely enough, I have no problems when I use a listbox:
DragAcceptFiles(ListBox1.Handle,True); works just fine.
But I need to use a ListView!

Any suggestions?

Maarten Veerman

CODE FROM TIP:
firs add ShellApi to th Uses clause

and this to the protected procedures

protected
   procedure WMDROPFILES (var Msg: TMessage); message WM_DROPFILES;

and tis after the implementation part like this:

implementation

uses Unit2;

{$R *.DFM}

procedure TForm1.WMDROPFILES (var Msg: TMessage);
var
 i,
 amount,
 size: integer;
 Filename: PChar;
 S: string;
 begin
 inherited;
 Amount := DragQueryFile(Msg.WParam, $FFFFFFFF, Filename, 255);
 for i := 0 to (Amount - 1) do
 begin
   size := DragQueryFile(Msg.WParam, i , nil, 0) + 1;
   Filename:= StrAlloc(size);
   DragQueryFile(Msg.WParam,i , Filename, size);
   s := Extractfileext(Filename);
 if s <> '.bmp' then
   continue
 else
   listbox1.items.add(StrPas(Filename));
   StrDispose(Filename);
 end;
 DragFinish(Msg.WParam);
end;

Then Enable the function
by declaring

 DragAcceptFiles(Form1.Handle, true);

Re: DragDrop Files from explorer to ListView

#937

Author: Jianfeng Zou
Date: Sat, 11 Jan 2003 11:58

95 lines
3613 bytes

I have a program whose aim is the same to you.
I use following code to solve this.we can catch WM_DROPFILES message in
application.Onmessage function.
You must add this code in form.create


  Application.OnMessage := AppMessage;

And

procedure TForm.AppMessage(var Msg: TMsg; var Handled: Boolean);
var
begin
  if (Msg.message = WM_DROPFILES) and (msg.hwnd = ListView.Handle) then
  begin
...
  end
end;




"Maarten Veerman" <M.T.Veerman@[nospam]student.tudelft.nl> wrote in message
news:avou1u$5h1$1@news.tudelft.nl...
> Hi,
>
> I have a problem with dropping files in a ListView. I use the code that
> everybody can find in the Delphipages TIPS section:
> http://www.delphipages.com/tips/thread.cfm?ID=95&SR=drag
> (See below for code)
>
> Anyway, I try setting the DragAcceptFiles like this:
> DragAcceptFiles(ListView1.Handle,True);
>
> When I drag files over the listview it seems like it will accept the
files,
> since the cursor changes. But when I drop the files, the
TForm1.WMDROPFILES
> procedure is not activated, so nothing is dropped.
>
> Strangely enough, I have no problems when I use a listbox:
> DragAcceptFiles(ListBox1.Handle,True); works just fine.
> But I need to use a ListView!
>
> Any suggestions?
>
> Maarten Veerman
>
> CODE FROM TIP:
> firs add ShellApi to th Uses clause
>
> and this to the protected procedures
>
> protected
>    procedure WMDROPFILES (var Msg: TMessage); message WM_DROPFILES;
>
> and tis after the implementation part like this:
>
> implementation
>
> uses Unit2;
>
> {$R *.DFM}
>
> procedure TForm1.WMDROPFILES (var Msg: TMessage);
> var
>  i,
>  amount,
>  size: integer;
>  Filename: PChar;
>  S: string;
>  begin
>  inherited;
>  Amount := DragQueryFile(Msg.WParam, $FFFFFFFF, Filename, 255);
>  for i := 0 to (Amount - 1) do
>  begin
>    size := DragQueryFile(Msg.WParam, i , nil, 0) + 1;
>    Filename:= StrAlloc(size);
>    DragQueryFile(Msg.WParam,i , Filename, size);
>    s := Extractfileext(Filename);
>  if s <> '.bmp' then
>    continue
>  else
>    listbox1.items.add(StrPas(Filename));
>    StrDispose(Filename);
>  end;
>  DragFinish(Msg.WParam);
> end;
>
> Then Enable the function
> by declaring
>
>  DragAcceptFiles(Form1.Handle, true);
>
>

Re: DragDrop Files from explorer to ListView

#938

Author: Maarten Veerman
Date: Sat, 11 Jan 2003 12:24

102 lines
4104 bytes

Thanks a lot!

"Jianfeng Zou" <zjf1998@21cn.com> wrote in message
news:avp0t3$f5a$1@mail.cn99.com...
> I have a program whose aim is the same to you.
> I use following code to solve this.we can catch WM_DROPFILES message in
> application.Onmessage function.
> You must add this code in form.create
>
>
>   Application.OnMessage := AppMessage;
>
> And
>
> procedure TForm.AppMessage(var Msg: TMsg; var Handled: Boolean);
> var
> begin
>   if (Msg.message = WM_DROPFILES) and (msg.hwnd = ListView.Handle) then
>   begin
> ...
>   end
> end;
>
>
>
>
> "Maarten Veerman" <M.T.Veerman@[nospam]student.tudelft.nl> wrote in
message
> news:avou1u$5h1$1@news.tudelft.nl...
> > Hi,
> >
> > I have a problem with dropping files in a ListView. I use the code that
> > everybody can find in the Delphipages TIPS section:
> > http://www.delphipages.com/tips/thread.cfm?ID=95&SR=drag
> > (See below for code)
> >
> > Anyway, I try setting the DragAcceptFiles like this:
> > DragAcceptFiles(ListView1.Handle,True);
> >
> > When I drag files over the listview it seems like it will accept the
> files,
> > since the cursor changes. But when I drop the files, the
> TForm1.WMDROPFILES
> > procedure is not activated, so nothing is dropped.
> >
> > Strangely enough, I have no problems when I use a listbox:
> > DragAcceptFiles(ListBox1.Handle,True); works just fine.
> > But I need to use a ListView!
> >
> > Any suggestions?
> >
> > Maarten Veerman
> >
> > CODE FROM TIP:
> > firs add ShellApi to th Uses clause
> >
> > and this to the protected procedures
> >
> > protected
> >    procedure WMDROPFILES (var Msg: TMessage); message WM_DROPFILES;
> >
> > and tis after the implementation part like this:
> >
> > implementation
> >
> > uses Unit2;
> >
> > {$R *.DFM}
> >
> > procedure TForm1.WMDROPFILES (var Msg: TMessage);
> > var
> >  i,
> >  amount,
> >  size: integer;
> >  Filename: PChar;
> >  S: string;
> >  begin
> >  inherited;
> >  Amount := DragQueryFile(Msg.WParam, $FFFFFFFF, Filename, 255);
> >  for i := 0 to (Amount - 1) do
> >  begin
> >    size := DragQueryFile(Msg.WParam, i , nil, 0) + 1;
> >    Filename:= StrAlloc(size);
> >    DragQueryFile(Msg.WParam,i , Filename, size);
> >    s := Extractfileext(Filename);
> >  if s <> '.bmp' then
> >    continue
> >  else
> >    listbox1.items.add(StrPas(Filename));
> >    StrDispose(Filename);
> >  end;
> >  DragFinish(Msg.WParam);
> > end;
> >
> > Then Enable the function
> > by declaring
> >
> >  DragAcceptFiles(Form1.Handle, true);
> >
> >
>
>

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