How to use Filter in Folderbrowserdialog

Question

I would like to know how do I put a filter on certain files using c#.

Good is more or less like this, I am making an application in c# that should open some types of files ( in the case .frm ), in the "manual" part which would be when the user selects 1 or more files to be loaded and passed in Datagridview he is using the filter without major problems .

 openFileDialog.Filter = "Form (*.frm)|*.frm|" + "All files (*.*)|*.*"; //Filtro de arquivos a serem selecionados

Note: I am using openFileDialog to make manual file selection.

In the second part ( that is the selection of a folder or a subfolder ) is the one that I have problems with when using this filter. I had already asked another question here that was

"How to pass filenames to a Datagridview using Folderbrowserdialog"

Now my other question is: How do I use the file selection filter in Folderbrowserdialog. Using Openfiledialog he already gave you this option to use the filter - as it is seen up there in my example - but in Folderbrowserdialog he does not give you this option to put a filter. I had already tried to make the filter in the same way as my example but it didn’t work. Follow the code part where I’m using Folderbrowserdialog.

 private void btnDiretorio_Click(object sender, EventArgs e)
        {

            this.grvShowFile.Rows.Clear();
            folderBrowserDialog.RootFolder = Environment.SpecialFolder.DesktopDirectory;
            folderBrowserDialog.SelectedPath = openFileDialog.InitialDirectory;
            folderBrowserDialog.ShowNewFolderButton = true;
            openFileDialog.Filter = "Form (*.frm)|*.frm"; //Filtro de arquivos a serem selecionados
            DialogResult result = folderBrowserDialog.ShowDialog();

            if (result == DialogResult.OK)
            {
                List<string> selectedPath = listaArquivos(folderBrowserDialog.SelectedPath);
                foreach (string s in selectedPath)
                {
                    grvShowFile.Rows.Add(Path.GetFileName(s), s); //Adiciona o nome e o caminho dos arquivos nas respectivas ordens ( Bendito seja o Path.GetFileName() )
                }
            }
        }

        public List<string> listaArquivos(string dir)
        {
            List<string> lstDirs = Directory.GetDirectories(dir).ToList();
            List<string> lstFiles = Directory.GetFiles(dir).ToList();
            List<string> lstFilesAux = new List<string>();
            foreach(string ldir in lstDirs)
                lstFilesAux = listaArquivos(ldir);

            lstFiles.AddRange(lstFilesAux);
            return lstFiles;
        }

Note: I used a List<> to check the directory and check the subdirectories if you have any.

Well I hope you explained my doubt well, every explanation is super welcome here.

Answer 1

Maybe your problem is not in the directory selection but in the files. I already answered something like this in another answer. You must use the Directory.GetFiles() with filter options:

public List<string> listaArquivos(string dir)
{
    List<string> lstDirs = Directory.GetDirectories(dir).ToList();
    List<string> lstFiles = Directory.GetFiles(dir, "*.frm", SearchOption.AllDirectories).ToList();
    List<string> lstFilesAux = new List<string>();
    foreach(string ldir in lstDirs)
        lstFilesAux = listaArquivos(ldir);

    lstFiles.AddRange(lstFilesAux);
    return lstFiles;
}

I put in the Github for future reference.

I still have doubts if the rest of the code is doing what you want. But without more information I could be wrong. Maybe what you want to do is something simpler:

private void btnDiretorio_Click(object sender, EventArgs e) {
    this.grvShowFile.Rows.Clear();
    folderBrowserDialog.RootFolder = Environment.SpecialFolder.DesktopDirectory;
    folderBrowserDialog.SelectedPath = openFileDialog.InitialDirectory;
    openFileDialog.Filter = "Form (*.frm)|*.frm"; //Filtro de arquivos a serem selecionados
    DialogResult result = folderBrowserDialog.ShowDialog();
    if (result == DialogResult.OK) {
        List<string> selectedPath = Directory.GetFiles(folderBrowserDialog.SelectedPath,
                                         "*.frm", SearchOption.AllDirectories).ToList();
        foreach (string s in selectedPath) grvShowFile.Rows.Add(Path.GetFileName(s), s); //Adiciona o nome e o caminho dos arquivos nas respectivas ordens ( Bendito seja o Path.GetFileName() )
    }
}

I put in the Github for future reference.

Answer 2

Well, since that example also worked for me, I think it’s a little better than using recursion.

public List<string> listaArquivos(string dir)
    {
        List<string> lstFiles = Directory.GetFiles(dir, "*.frm", SearchOption.AllDirectories).ToList();         
        return lstFiles;
    }