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

Ritsaert Hornstra Ritsaert Hornstra · Accepted Answer · 2010-02-05T10:51:32

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;

Application Configuration File Not Being Read When Application Called via ShellExecute

2 Answers