In Windows7 I am using a customized Open File Dialog( WPF application). My Open File dialog is derived from Microsoft.Win32.CommonDialog. The dialog have old look, how to change this to new look (windows7 file dialog look(Explorer style)).

Code portion:

  private const int OFN_ENABLESIZING = 0x00800000;
            private const int OFN_EXPLORER = 0x00080000;
            private const int OFN_ENABLEHOOK = 0x00000020;

     protected override bool RunDialog(IntPtr hwndOwner)
            {
                     OPENFILENAME_I.WndProc proc = new OPENFILENAME_I.WndProc(this.HookProc);
                    OPENFILENAME_I ofn = new OPENFILENAME_I();
this._charBuffer = CharBuffer.CreateBuffer(0x2000);
                    if (this._fileNames != null)
                    {
                        this._charBuffer.PutString(this._fileNames[0]);
                    }
                    ofn.lStructSize = Marshal.SizeOf(typeof(OPENFILENAME_I));
                    ofn.hwndOwner = hwndOwner;
                    ofn.hInstance = IntPtr.Zero;
                    ofn.lpstrFilter = MakeFilterString(this._filter, this.DereferenceLinks);
                    ofn.nFilterIndex = this._filterIndex;
                    ofn.lpstrFile = this._charBuffer.AllocCoTaskMem();
                    ofn.nMaxFile = this._charBuffer.Length;
                    ofn.lpstrInitialDir = this._initialDirectory;
                    ofn.lpstrTitle = this._title;
                    ofn.Flags =  OFN_EXPLORER | OFN_ENABLESIZING | OFN_ENABLEHOOK;
                    ofn.lpfnHook = proc;
                    ofn.FlagsEx = 0x1000000 ;

                     NativeMethods.GetOpenFileName(ofn); // 
        }

[SecurityCritical, SuppressUnmanagedCodeSecurity, DllImport("comdlg32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        internal static extern bool GetOpenFileName([In, Out] OPENFILENAME_I ofn);