[英]Delphi - Drag & Drop with ListView
Good evening :-)! 晚上好 :-)!
I have this code to use Drag & Drop method for files : 我有这个代码使用拖放方法的文件 :
TForm1 = class(TForm)
...
public
procedure DropFiles(var msg: TMessage ); message WM_DROPFILES;
end;
procedure TForm1.FormCreate(Sender: TObject)
begin
DragAcceptFiles(ListView1.Handle, True);
end;
procedure TForm1.DropFiles(var msg: TMessage );
var
i, count : integer;
dropFileName : array [0..511] of Char;
MAXFILENAME: integer;
begin
MAXFILENAME := 511;
count := DragQueryFile(msg.WParam, $FFFFFFFF, dropFileName, MAXFILENAME);
for i := 0 to count - 1 do
begin
DragQueryFile(msg.WParam, i, dropFileName, MAXFILENAME);
Memo1.Lines.Add(dropFileName);
end;
DragFinish(msg.WParam);
end;
In area of ListView is DragCursor , but in Memo1 aren't any records. 在ListView区域是DragCursor ,但在Memo1 中没有任何记录。 When I use for example ListBox and method DragAcceptFiles(ListBox1.Handle, True) ever is fine.
当我使用例如ListBox和方法DragAcceptFiles(ListBox1.Handle,True)时 , 一切都很好。
ListView property DragMode I set to dmAutomatic . ListView属性DragMode我设置为dmAutomatic 。
Thanks :-) 谢谢 :-)
You've called DragAcceptFiles for the ListView, so Windows sends the WM_DROPFILES to your ListView and not to your Form. 您已为ListView调用DragAcceptFiles,因此Windows将WM_DROPFILES发送到ListView而不是表单。 You have to catch the WM_DROPFILES message from the ListView.
您必须从ListView捕获WM_DROPFILES消息。
private
FOrgListViewWndProc: TWndMethod;
procedure ListViewWndProc(var Msg: TMessage);
// ...
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
// Redirect the ListView's WindowProc to ListViewWndProc
FOrgListViewWndProc := ListView1.WindowProc;
ListView1.WindowProc := ListViewWndProc;
DragAcceptFiles(ListView1.Handle, True);
end;
procedure TForm1.ListViewWndProc(var Msg: TMessage);
begin
// Catch the WM_DROPFILES message, and call the original ListView WindowProc
// for all other messages.
case Msg.Msg of
WM_DROPFILES:
DropFiles(Msg);
else
if Assigned(FOrgListViewWndProc) then
FOrgListViewWndProc(Msg);
end;
end;
Your problem is, you're registering the list view window as a drop target, but handling the WM_DROPFILES
message in the form class. 您的问题是,您正在将列表视图窗口注册为放置目标,但是在表单类中处理
WM_DROPFILES
消息。 The message is sent to the list view control, you should handle the message there. 消息被发送到列表视图控件,您应该在那里处理消息。
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