Application Configuration File Not Being Read When Application Called via ShellExecute

Question

I have a .NET application that is launched via a Delphi program using ShellExecute. Unfortunately when launched in this manner, the application does not seem to be reading its app.config file correctly, as if the file did not exist.

I have tried testing the application in other scenarios, e.g. calling from a shortcut with the the working directory set to a different folder and it runs fine.

[Edit]The Environment.CurrentDirectory property returns the directory of the Delphi program.

Any ideas would be really appreciated.

Cheers,

James

Answer 1

Well I researched it a bit and there does not appear to be a solution that is both simple and elegant.

The easiest way round it seems to be to call an intermediate .NET program that then runs the target application via Process.Start and passes the parameters on. Not ideal but it's simpler than the other solutions I have found so far.

Answer 2

Apparently the process you spawn cannot handle the fact that the working directory is not it's own.

You could open the file using CreateProcess(). I have a small example with waiting for (but you can clip that out):

procedure ExecuteAndWaitFor(CommandLine, CurrentDirectory: string; Environment: TStrings);
var
  List: TList;
  ActiveWin: HWnd;
  i: Integer;
  Ret: Longword;
  SI: TStartupInfo;
  PI: TProcessInformation;
  MadeForeground: Boolean;
  AssociatedCommandLine: string;
begin
  // find the association ot use
  AssociatedCommandLine := GetAssociatedCommandLine(CommandLine);
  // first we create a list of windows which we need to block...
  List := TList.Create;
  try
    ActiveWin := Windows.GetForegroundWindow;
    // get the list of all visible and active top windows...
    if not Windows.EnumThreadWindows(GetCurrentThreadId,@InternallyThreadWindowCallback,Integer(List)) then RaiseLastOSError;
    // disable all those windows...
    for i := 0 to List.Count - 1 do Windows.EnableWindow(HWnd(List[i]),False);
    try
      // create the process
      System.FillChar(SI,sizeof(SI),0);
      SI.cb := sizeof(SI.cb);
      // todo: environment
      if not Windows.CreateProcess(nil,PChar(AssociatedCommandLine),nil,nil,False,NORMAL_PRIORITY_CLASS,nil,PChar(CurrentDirectory),SI,PI) then RaiseLastOSError;
      // wait until the process is finished...
      MadeForeGround := False;
      repeat
        // process any pending messages in the thread's message queue
        Application.ProcessMessages;
        if not MadeForeground then begin
          Windows.EnumThreadWindows(PI.dwThreadId,@InternallyTopWindowToForeMost,Integer(@MadeForeGround));
        end;
        // wait for a message or the process to be finished
        Ret := Windows.MsgWaitForMultipleObjects(1, PI.hProcess, False, INFINITE, QS_ALLINPUT);
        if Ret = $FFFFFFFF then RaiseLastOSError;
      until Ret = 0;
      // free the process handle
      Windows.CloseHandle(PI.hProcess);
      WIndows.CloseHandle(PI.hThread);
    finally
      // enable all those windows
      for i := 0 to List.Count - 1 do Windows.EnableWindow(HWnd(List[i]), True);
    end;
    Windows.SetForegroundWindow(ActiveWin);
  finally
    List.Free;
  end;
end;

Added some missing utility functions:

uses
  SysUtils, Registry;

function GetAssociatedFile(const Extension: string; const RemoveParameters: Boolean = False): string;
var
  FileClass: string;
  Reg: TRegistry;
  Position: Integer;
begin
  // initialize
  Result := '';
  // create registry entry
  Reg := TRegistry.Create(KEY_EXECUTE);
  try
    // find the given extension
    Reg.RootKey := HKEY_CLASSES_ROOT;
    FileClass := '';
    if Reg.OpenKeyReadOnly(ExtractFileExt(Extension)) then begin
      FileClass := Reg.ReadString('');
      Reg.CloseKey;
    end;
    if FileClass <> '' then begin
      if Reg.OpenKeyReadOnly(FileClass + '\Shell\Open\Command') then begin
        Result := Reg.ReadString('');
        Reg.CloseKey;
      end;
    end;
  finally
    Reg.Free;
  end;
  // remove the additional parameters
  Position := Pos('"%1"', Result);
  if RemoveParameters and (Position > 0) then
    Result := Trim(Copy(Result, 1, Position - 1))
  else
    Result := Trim(Result);
end;

function GetAssociatedCommandLine(const CommandLine: string): string;
begin
  // build the command line with the associated file in front of it
  Result := Trim(GetAssociatedFile(CommandLine, True) + ' ') + '"' + CommandLine + '"';
end;

function InternallyThreadWindowCallback(Window: HWnd; Data: Longint): Bool; stdcall;
var
  List: TList;
begin
  Result := True;
  if (not IsWindowVisible(Window)) or (not IsWindowEnabled(Window)) then Exit;
  List := TList(Data);
  List.Add(Pointer(Window));
end;

function InternallyTopWindowToForeMost(Window: HWnd; Data: LongInt): Bool; stdcall;
begin
  Result := True;
  if (not IsWindowVisible(Window)) or (not IsWindowEnabled(Window)) then Exit;
  SetForegroundWindow(Window);
  PBoolean(Data)^ := True;
end;