3
我正在使用Delphi编写一个简单的应用程序,该应用程序需要接受已删除的目录名称。虽然我使用的是Delphi,但这个程序是直接Windows API(没有VCL,没有面向对象的东西),就像它在普通的C中一样。使用对话框时,无法使DragAcceptFiles正常工作
我有一些代码已经在使用普通窗口工作了(由CreateWindowEx )。当我将该代码转换为使用对话框时,拖放功能打破了,我找不到原因。
这是(部分)我有工作的罚款代码:
function WndProc (Wnd : hWnd; Msg, wParam, lParam : DWORD) : DWORD; stdcall; { main application/window handler function } const DROPPED_FILE_COUNT = -1; var FileCnt : integer; { number of files dropped } Filename : packed array[0..MAX_PATH] of char; { filename buffer } DropInfo : HDROP absolute wParam; { wParam points to Drop...} I : integer; { for loop } begin WndProc := 0; { let the Windows default handler take care of everything } case msg of WM_CREATE: begin InitCommonControls; if CreateWindowEx(WS_EX_CLIENTEDGE or WS_EX_RIGHTSCROLLBAR, 'LISTBOX', nil, WS_CHILD or WS_HSCROLL or WS_VSCROLL or WS_CLIPSIBLINGS or WS_CLIPCHILDREN or WS_VISIBLE or LBS_NOINTEGRALHEIGHT, 0, 0, 0, 0, Wnd, IDC_LISTBOX, hInstance, nil) = 0 then begin MessageBox(Wnd, 'Couldn''t create the listbox', 'Main Window', MB_OK); WndProc := -1; end; { let Windows know that we accept files being dragged over our client} { area. } DragAcceptFiles(Wnd, TRUE); { tell the listbox to use a nice font } SendMessage(GetDlgItem(Wnd, IDC_LISTBOX), WM_SETFONT, GetStockObject(DEFAULT_GUI_FONT), 0); exit; end; { WM_CREATE } WM_DROPFILES: begin { one or more files have been dropped on us! } FileCnt := DragQueryFile(DropInfo, DROPPED_FILE_COUNT, nil, 0); for I := 0 to FileCnt - 1 do begin { get the dropped files names and add them to the listbox } DragQueryFile(DropInfo, I, Filename, sizeof(Filename)); ListBox_AddString(GetDlgItem(Wnd, IDC_LISTBOX), Filename); end; { tell Windows that we are done grabbing the dropped files } DragFinish(DropInfo); exit; end; { WM_DROPFILES } ... followed by other stuff that has nothing to do with drag and drop ...
我转换是这样的:
procedure ExecWM_INITDIALOG(wnd : hWnd); begin { ensure that the listbox isn't accepting dropped files } DragAcceptFiles(GetDlgItem(Wnd, IDC_DIRECTORIES), FALSE); { ensure the main dialog window accept dropped files } DragAcceptFiles(Wnd, TRUE); { load the current values in the registry } LoadRegistrySettings(RegistryKey, RegistrySettings, RegistrySettingsCount) end; procedure ExecWM_DROPFILES(Wnd : hWnd; wParam : word; lParam : longint); const DROPPED_FILE_COUNT = -1; var FileCnt : integer; { number of files dropped } Filename : packed array[0..MAX_PATH] of char; { filename buffer } DropInfo : HDROP absolute wParam; { wParam points to Drop...} I : integer; { for loop } begin { one or more files have been dropped on us! } { -->>> The problem seems to show up at this statement: } { the DropInfo (wParam) has a value that seems too low ($20) } { when using the code that works the value is much larger } FileCnt := DragQueryFile(DropInfo, DROPPED_FILE_COUNT, nil, 0); for I := 0 to FileCnt - 1 do begin { get the dropped files names and add them to the listbox } DragQueryFile(DropInfo, I, Filename, sizeof(Filename)); ListBox_AddString(GetDlgItem(Wnd, IDC_DIRECTORIES), Filename); end; { tell Windows that we are done grabbing the dropped files } DragFinish(DropInfo); end; function BackupConfigProc(wnd : hWnd; msg : word; wParam : word; lParam : longint) : bool; stdcall; begin BackupConfigProc := FALSE; { default return value } case msg of WM_COMMAND: begin ExecWM_COMMAND (wnd, wParam, lParam); BackupConfigProc := TRUE; end; WM_DROPFILES: begin ExecWM_DROPFILES(Wnd, wParam, lParam); //BackupConfigProc := TRUE; { this was a shot in the dark } end; WM_INITDIALOG: begin ExecWM_INITDIALOG (wnd); BackupConfigProc := TRUE; end; WM_CLOSE: begin EndDialog(wnd, 0); { and return the default FALSE } end; end; end; begin DialogBox(hInstance, 'BackupConfigDlg', 0, @BackupConfigProc); end.
它看起来像DropInfo(wParam参数)的值收到通过对话框是无效的(因为它的值比非对话代码所收到的值低得多)。
我将非常感谢所有能够了解Dialog版本为什么不起作用以及需要做什么才能使其工作的人员。
谢谢,
约翰。
你是我的极度尴尬,绝对正确!我刚刚意识到,我复制的一些代码来自我在Windows 3.1时代编写的程序。适当调整参数后,它工作得很好。谢谢你,我对这个愚蠢的错误表示歉意。 – Hex440bx 2011-04-26 12:30:57