Delphi中的SelectDirectory对话框如何动态验证突出显示的文件夹?

如果你使用 ShBrowseForFolder API函数。我想德尔菲有一个 SelectDirectory 包装该函数的版本,尽管包装器可能无法提供足够的访问权限来处理该函数。你需要包括 callback function 对于 lpfn 带有此签名的参数:

function BrowseCallbackProc(Wnd: HWnd; uMsg: UInt; lParam, lpData: LParam): Integer; stdcall;

当选择更改时,对话框将调用您提供的函数 bffm_SelChanged 作为 uMsg 参数。第三个参数将是表示当前选择的pidl,因此您可能需要调用 ShGetPathFromIDList 以确定字符串名称。您可以通过将消息发送回对话框的窗口句柄来控制“确定”按钮。 Wnd 参数。例如:

SendMessage(Wnd, bffm_EnableOK, 0, 0); // disable the button
SendMessage(Wnd, bffm_EnableOK, 0, 1); // enable the button

不要忘记重新启用按钮 好的 为无效选择禁用后的选择。

如果有效选择的条件是目录应包含具有特定名称的文件,请确保包含 bif_BrowseIncludeFiles 标记以便人们可以查看文件。

作为对@rob优秀答案的补充。

请参见此代码。

uses  ShlObj;

function BrowseCallbackProc(hwnd: HWND; MessageID: UINT; lParam: LPARAM; lpData: LPARAM): Integer; stdcall;
var
    DirName:  array[0..MAX_PATH] of Char;
    pIDL   :  pItemIDList;
begin
  case  MessageID    of
    BFFM_INITIALIZED:SendMessage(hwnd, BFFM_SETSELECTION, 1, lpData);
    BFFM_SELCHANGED :begin
                        pIDL := Pointer(lParam);
                        if  Assigned(PIDL) then
                        begin
                          SHGetPathFromIDList(pIDL, DirName);
                          if DirectoryExists(DirName) then
                           if (ExtractFileName(DirName)='config') then    //you can add more validations here
                            SendMessage(hwnd, BFFM_ENABLEOK, 0, 1) //enable the ok button
                           else
                            SendMessage(hwnd, BFFM_ENABLEOK, 0, 0) //disable the ok button
                          else
                          SendMessage(hwnd, BFFM_ENABLEOK, 0, 0);
                        end
                        else
                          SendMessage(hwnd, BFFM_ENABLEOK, 0, 0);
                     end;
  end;

  Result := 0;
end;

function SelectFolderDialogExt(Handle: Integer; var SelectedFolder: string): Boolean;
var
  ItemIDList: PItemIDList;
  JtemIDList: PItemIDList;
  DialogInfo: TBrowseInfo;
  Path: PAnsiChar;
begin
  Result := False;
  Path   := StrAlloc(MAX_PATH);
  SHGetSpecialFolderLocation(Handle, CSIDL_DRIVES, JtemIDList);
  with DialogInfo do
  begin
    pidlRoot      := JtemIDList;
    //ulFlags       := BIF_RETURNONLYFSDIRS;     //only select directories
    hwndOwner     := GetActiveWindow;
    SHGetSpecialFolderLocation(hwndOwner, CSIDL_DRIVES, JtemIDList);
    pszDisplayName := StrAlloc(MAX_PATH);
    lpszTitle       := PChar('Select a folder');
    lpfn            := @BrowseCallbackProc;
    lParam            := LongInt(PChar(SelectedFolder));
  end;

  ItemIDList := SHBrowseForFolder(DialogInfo);

  if (ItemIDList <> nil) then
    if SHGetPathFromIDList(ItemIDList, Path) then
    begin
      SelectedFolder := Path;
      Result         := True;
    end;
end;

执行

if SelectFolderDialogExt(Handle, SelectedDir) then
  ShowMessage(SelectedDir);