CODEWITHSUNDEEP
c#
Eu Lupu
Eu Lupu

Reputation: 371

OpenFileDialog default path

using (var openFileDialog1 = new OpenFileDialog())
        {
            openFileDialog1.Reset();
            if (!string.IsNullOrEmpty(ExcelFilePath))
            {
                string fileName = Path.GetFileName(ExcelFilePath);
                string fileExt = Path.GetExtension(ExcelFilePath);
                //Avoid "you can't open this location using this program file" dialog 
                //if there is a file name in the path strip it )
                if (!string.IsNullOrEmpty(fileName))
                    initialDirectory = Path.GetDirectoryName(ExcelFilePath);  
      //if not let it be   
                else
                    initialDirectory = ExcelFilePath;

            openFileDialog1.InitialDirectory = initialDirectory;
            }
            else
                openFileDialog1.InitialDirectory = "c:\\";
            openFileDialog1.Filter = "Excel files (*.xls or *.xlsx)|*.xls;*.xlsx";
            //openFileDialog1.Filter = "xls files (*.xls)|*.xls|xlsx files(*.xlsx)|.xlsx";
            openFileDialog1.FilterIndex = 2;
            openFileDialog1.RestoreDirectory = false;
            openFileDialog1.CheckFileExists = true;
            openFileDialog1.CheckPathExists = true;
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                var browseSelectionMade = BrowseSelectionMade;
                if (browseSelectionMade!=null)
                    browseSelectionMade(this, new DataEventArgs<string>(openFileDialog1.FileName));
            }
        }

Regardless of whether or not I set RestoreDirectory to true, I will always browse to the LAST used directory if my initial directory is set to a path that doesn't exist. Where is the last used directory saved by OpenFileDialog? And is there a way to override this behavior? (e.g. I always want to set it to C:\ if the initial directory doesn't exist?)

Upvotes: 28

Views: 122144

Answers (8)

Chipset31
Chipset31

Reputation: 31

Edit: After consulting with a more knowledgeable friend, perhaps the better solution is, in hindsight, obvious. Just store your own registry key in HKEY_CURRENT_USER\SOFTWARE\YourCompanyOrAppName\Whatevs or something similar (not sure on best practices, or which folders you have read/write access to, do your own research in that) and avoid this problem altogether. By simply letting the user navigate to where they want once, and then storing the path in the registry (as a normal string, and not a PIDL) and retrieving that path the next time. For reference, see the MSDN articles on the Registry and RegistryKey classes, and their example in the RegistryKey/Methods/SetValue article. Still, I'll leave this post as is, as a point of curiosity, or if someone has a very specific problem and needs this solution. As always, good luck!

For any poor soul wandering through here in the future, it seems I figured out how to find the last used directory. Just like stated previously, it's stored in the registry, more specifically in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\ComDlg32\OpenSavePidlMRU\ Here is a set of folders for each file extension, including a "*" for unknown file extensions. I'll do this for txt files, change the path as needed. To access this path we make a RegistryKey and call OpenSubKey (BTW, full code below)

string RegistryPath = @"Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\ComDlg32\\OpenSavePidlMRU\\txt";
RegistryKey rk = Registry.CurrentUser.OpenSubKey(RegistryPath);

In here is a set of entries which all contain PIDLs (we'll get to that) of the last opened or saved items. DO NOTE: the folder name OpenSavePidlMRU, i've seen called just OpenSaveMRU, and seems to be for versions older than win 10. Also in here is an entry called "MRUListEx", MRU stands for "Most Recently Used". In this entry is an index of which item was... well, most recently used. So if I have 10 entries, named 0 to 9, and 9 was the last used, the first byte in MRUListEx will be 0x09. So for:

byte[] mrulistex = (byte[])rk.GetValue("MRUListEx");
byte Last = mrulistex[0];

Last will equal 0x09 (on my system) Then we call GetValue again but for that entry

byte[] LastPathByteArray = (byte[])rk.GetValue(Last.ToString());

And here's where things get problematic, as this won't return a byte array where each byte is a character in our filepath, it returns what's known as a PIDL. While the byte array will seem to contain the path, in both char and wide char, it also contains a bunch of gibberish that can't be easily converted. I won't pretend to understand it, but https://stackoverflow.com/a/4318663 provides a way to convert this to a string. (see code below)

string LastPath = GetPathFromPIDL(LastPathByteArray);

And we're done. PLEASE NOTE this doesn't necessarily represent a good solution, but I wasn't able to find much official documentation on this in my half hour of digging. And obviously this code doesn't check if the registry path is correct, if the registry keys exist, or do much error checking at all, but this does at least work.

using Microsoft.Win32; //for the registry class
using System.Runtime.InteropServices; //for converting the PIDL

//GetPathFromPIDL from matt.schechtman at https://stackoverflow.com/a/4318663
[DllImport("shell32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SHGetPathFromIDListW(IntPtr pidl, MarshalAs(UnmanagedType.LPTStr)] StringBuilder pszPath);
private string GetPathFromPIDL(byte[] byteCode)
{
    //MAX_PATH = 260
    StringBuilder builder = new StringBuilder(260);

    IntPtr ptr = IntPtr.Zero;
    GCHandle h0 = GCHandle.Alloc(byteCode, GCHandleType.Pinned);
    try
    {
        ptr = h0.AddrOfPinnedObject();
    }
    finally
    {
        h0.Free();
    }

    SHGetPathFromIDListW(ptr, builder);

    return builder.ToString();
}

public void OnClick_Button_OpenFile(object sender, RoutedEventArgs e)
{
    string RegistryPath = @"Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\ComDlg32\\OpenSavePidlMRU\\txt";
    RegistryKey rk = Registry.CurrentUser.OpenSubKey(RegistryPath);
    byte[] mrulistex = (byte[])rk.GetValue("MRUListEx");
    byte Last = mrulistex[0];
    byte[] LastPathByteArray = (byte[])rk.GetValue(Last.ToString());
    string LastPath = GetPathFromPIDL(LastPathByteArray);

    // Configure open file dialog box
    Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();`
    dlg.InitialDirectory = LastPath;
    result = dlg.ShowDialog();
    if (result == true)
    {
        string filename = dlg.FileName;
    }
    //etc etc, rest of your code
}

Good luck.

Upvotes: 2

Krzysztof Skowronek
Krzysztof Skowronek

Reputation: 2936

For future me

remember to do:

            try        
            {
                result = dialog.ShowDialog(Window);
            }
            catch
            {
                dialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
                result = dialog.ShowDialog(Window);
            }

This helps in the situation when user opened file from location, that does not longer exists (ex. USB stick, mapped network drive) - ShowDialog throws exception if InitialDirectory is invalid.

Upvotes: 1

Michal Pokluda
Michal Pokluda

Reputation: 390

In case you're using file name stored in some string, it's better to use Path to cut the file name (on my W10 the open dialog doesn't open in initial directory, if I supply just file name):

    if (!System.IO.Directory.Exists(filename))
    {
        openDlg.InitialDirectory =
            System.IO.Path.GetDirectoryName(filename);
    }

Upvotes: 0

Hans Passant
Hans Passant

Reputation: 941277

Where is the last used directory saved?

It is stored in the registry. The exact location depends on the Windows version, for Win7 it is HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\ComDlg32. A quick look with regedit ought to convince you that you don't want to mess with that.

The simple workaround is to provide a valid path. If the one you calculate isn't valid, Directory.Exists returns false, then provide a valid one. Like the Documents folder returned by Environment.GetFolderPath(). Then again, nothing wrong with the last used one either, the user will easily recognize it with good odds that it happens to be close to the desired one.

Upvotes: 19

Du D.
Du D.

Reputation: 5300

I don't think there is anything built in for that. Just check before you open the dialog:

if (!Directory.Exists(initialDirectory))
{
    openFileDialog1.InitialDirectory = @"C:\";
}

Upvotes: 6

DeveloperDan
DeveloperDan

Reputation: 4684

Also, to set the default extension you should set FilterIndex property instead of DefaultExt. see: https://stackoverflow.com/a/6104319/381082

Here's a good article on the OpenFileDialog in C#: http://www.c-sharpcorner.com/uploadfile/mahesh/openfiledialog-in-C-Sharp/

Upvotes: 2

Jetti
Jetti

Reputation: 2458

It seems like all you need to do is the following:

string path; // this is the path that you are checking.
if(Directory.Exists(path)) {
    openFileDialog1.InitialDirectory = path;
} else {
    openFileDialog1.InitialDirectory = @"C:\";
}

That is unless I'm missing something.

Upvotes: 48

rie819
rie819

Reputation: 1249

Check to see if the ExcelFilePath exists, you check to see if it's null or empty, however if before your block you check to see if the directory exists, and if it doesn't reset the value to an empty string you should be golden.

(yes you'll need to apply your file name logic etc earlier) however once you've parsed all of that out, it's trivial to determine if the directory exits

if (!Directory.Exists(excelPath))
{
    ExcelFilePath = String.Empty;
}

Upvotes: 3

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