Question

I can’t use OpenFileDialog in my application.

As an alternative I use GetOpenFileName() method:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace Reader
{
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public class OpenFileName
    {
        public int lstructSize;
        public IntPtr hwndOwner;
        public IntPtr hInstance;
        public string lpstrFilter = null;
        public string lpstrCustomFilter = null;
        public int lMaxCustomFilter;
        public int lFilterIndex;
        public string lpstrFile = null;
        public int lMaxFile = 0;
        public string lpstrFileTitle = null;
        public int lMaxFileTitle = 0;
        public string lpstrInitialDir = null;
        public string lpstrTitle = null;
        public int lFlags;
        public ushort nFileOffset;
        public ushort nFileExtension;
        public string lpstrDefExt = null;
        public int lCustData;
        public int lpfHook;
        public int lpTemplateName;
    }

    public class OpenDialog
    {
        [DllImport("Comdlg32.dll",CharSet = CharSet.Auto)]
        public static extern bool GetOpenFileName([In, Out] OpenFileName ofn);
    }
}

And then use it in OnClick event of a button like this:

OpenFileName qofn = new OpenFileName();

qofn.lstructSize = Marshal.SizeOf(qofn);
qofn.lpstrFile = "";
qofn.lMaxFile = 256;
qofn.lpstrFileTitle = "";
qofn.lMaxFileTitle = 64;
qofn.hInstance = this.Handle;
source.Text = "Wait...";
if (OpenDialog.GetOpenFileName(qofn))
{
    MessageBox.Show("ofn.file: " + qofn. lpstrFile );
}

When application runs and button is clicked and I try to open file this is what happens:

1st try:

it returns the path to my file, but instead of
c:\dira\dirb\dirc\filename.ext
I have
c:\dira\dirb\dircfilename.ext
without ‘\’ before the name of the file

2nd try

Everything is OK

next:
there are random crashes, e.g. random access violation, or GUI freezes and application’s process can’t be kiled even in task manager, or other errors.

Usually dialog works 2-3 times before application crashes for good.

What is wrong with my code?

EDIT:

I can’t use OpenFileDialog. I’m using WinPE 4.0 (Windows Assessment and Deployment Kit ADK). When I try OpenFileDIalog, it throws run time error 80040111. It’s probably because the core is not supported (just like Server Core doesn’t support OpenFileDialog, the error’s the same). Probably on WinPE 4.0 they use GetOpenFileName in applications such as notepad. And it works for them.

Answer 1

OK, I found this microsoft sample and it works:

// Copyright
// Microsoft Corporation
// All rights reserved

// OpenFileDlg.cs

using System;
using System.Text;
using System.Runtime.InteropServices;

/*
typedef struct tagOFN { 
  DWORD         lStructSize; 
  HWND          hwndOwner; 
  HINSTANCE     hInstance; 
  LPCTSTR       lpstrFilter; 
  LPTSTR        lpstrCustomFilter; 
  DWORD         nMaxCustFilter; 
  DWORD         nFilterIndex; 
  LPTSTR        lpstrFile; 
  DWORD         nMaxFile; 
  LPTSTR        lpstrFileTitle; 
  DWORD         nMaxFileTitle; 
  LPCTSTR       lpstrInitialDir; 
  LPCTSTR       lpstrTitle; 
  DWORD         Flags; 
  WORD          nFileOffset; 
  WORD          nFileExtension; 
  LPCTSTR       lpstrDefExt; 
  LPARAM        lCustData; 
  LPOFNHOOKPROC lpfnHook; 
  LPCTSTR       lpTemplateName; 
#if (_WIN32_WINNT >= 0x0500)
  void *        pvReserved;
  DWORD         dwReserved;
  DWORD         FlagsEx;
#endif // (_WIN32_WINNT >= 0x0500)
} OPENFILENAME, *LPOPENFILENAME; 
*/

[ StructLayout( LayoutKind.Sequential, CharSet=CharSet.Auto )]  
public class OpenFileName 
{
    public int      structSize = 0;
    public IntPtr   dlgOwner = IntPtr.Zero; 
    public IntPtr   instance = IntPtr.Zero;

    public String   filter = null;
    public String   customFilter = null;
    public int      maxCustFilter = 0;
    public int      filterIndex = 0;

    public String   file = null;
    public int      maxFile = 0;

    public String   fileTitle = null;
    public int      maxFileTitle = 0;

    public String   initialDir = null;

    public String   title = null;   

    public int      flags = 0; 
    public short    fileOffset = 0;
    public short    fileExtension = 0;

    public String   defExt = null; 

    public IntPtr   custData = IntPtr.Zero;  
    public IntPtr   hook = IntPtr.Zero;  

    public String   templateName = null; 

    public IntPtr   reservedPtr = IntPtr.Zero; 
    public int      reservedInt = 0;
    public int      flagsEx = 0;
}

public class LibWrap
{
    //BOOL GetOpenFileName(LPOPENFILENAME lpofn);

    [ DllImport( "Comdlg32.dll", CharSet=CharSet.Auto )]                
    public static extern bool GetOpenFileName([ In, Out ] OpenFileName ofn );   
}

public class App
{
    public static void Main()
    {
        OpenFileName ofn = new OpenFileName();

        ofn.structSize = Marshal.SizeOf( ofn );

        ofn.filter = "Log files\0*.log\0Batch files\0*.bat\0";

        ofn.file = new String( new char[ 256 ]);
        ofn.maxFile = ofn.file.Length;

        ofn.fileTitle = new String( new char[ 64 ]);
        ofn.maxFileTitle = ofn.fileTitle.Length;    

        ofn.initialDir = "C:\\";
        ofn.title = "Open file called using platform invoke...";
        ofn.defExt = "txt";

        if( LibWrap.GetOpenFileName( ofn ))
        {
            Console.WriteLine( "Selected file with full path: {0}", ofn.file );
            Console.WriteLine( "Selected file name: {0}", ofn.fileTitle );
            Console.WriteLine( "Offset from file name: {0}", ofn.fileOffset );
            Console.WriteLine( "Offset from file extension: {0}", ofn.fileExtension );
        }
    }
}