这是极端的，但是我使用名为FILE_TYPES的2列数据库表构建了一个动态的、数据库驱动的过滤器，字段名为EXTENSION和DOCTYPE:

---------------------------------
| EXTENSION  |  DOCTYPE         |
---------------------------------
|   .doc     |  Document        |
|   .docx    |  Document        |
|   .pdf     |  Document        |
|   ...      |  ...             |
|   .bmp     |  Image           |
|   .jpg     |  Image           |
|   ...      |  ...             |
---------------------------------

显然，我有许多不同的类型和扩展，但在本例中我将其简化。这是我的函数:

    private static string GetUploadFilter()
    {
        // Desired format:
        // "Document files (*.doc, *.docx, *.pdf)|*.doc;*.docx;*.pdf|"
        // "Image files (*.bmp, *.jpg)|*.bmp;*.jpg|"

        string filter = String.Empty;
        string nameFilter = String.Empty;
        string extFilter = String.Empty;

        // Used to get extensions
        DataTable dt = new DataTable();
        dt = DataLayer.Get_DataTable("SELECT * FROM FILE_TYPES ORDER BY EXTENSION");

        // Used to cycle through doctype groupings ("Images", "Documents", etc.)
        DataTable dtDocTypes = new DataTable();
        dtDocTypes = DataLayer.Get_DataTable("SELECT DISTINCT DOCTYPE FROM FILE_TYPES ORDER BY DOCTYPE");

        // For each doctype grouping...
        foreach (DataRow drDocType in dtDocTypes.Rows)
        {
            nameFilter = drDocType["DOCTYPE"].ToString() + " files (";

            // ... add its associated extensions
            foreach (DataRow dr in dt.Rows)
            {
                if (dr["DOCTYPE"].ToString() == drDocType["DOCTYPE"].ToString())
                {
                    nameFilter += "*" + dr["EXTENSION"].ToString() + ", ";
                    extFilter += "*" + dr["EXTENSION"].ToString() + ";";
                }                    
            }

            // Remove endings put in place in case there was another to add, and end them with pipe characters:
            nameFilter = nameFilter.TrimEnd(' ').TrimEnd(',');
            nameFilter += ")|";
            extFilter = extFilter.TrimEnd(';');
            extFilter += "|";

            // Add the name and its extensions to our main filter
            filter += nameFilter + extFilter;

            extFilter = ""; // clear it for next round; nameFilter will be reset to the next DOCTYPE on next pass
        }

        filter = filter.TrimEnd('|');
        return filter;
    }

    private void UploadFile(string fileType, object sender)
    {            
        Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
        string filter = GetUploadFilter();
        dlg.Filter = filter;

        if (dlg.ShowDialog().Value == true)
        {
            string fileName = dlg.FileName;

            System.IO.FileStream fs = System.IO.File.OpenRead(fileName);
            byte[] array = new byte[fs.Length];

            // This will give you just the filename
            fileName = fileName.Split('\\')[fileName.Split('\\').Length - 1];
            ...

应该生成如下所示的过滤器:

要过滤图像文件，请使用下面的代码示例。

//Create a new instance of openFileDialog
OpenFileDialog res = new OpenFileDialog();

//Filter
res.Filter = "Image Files|*.jpg;*.jpeg;*.png;*.gif;*.tif;...";

//When the user select the file
if (res.ShowDialog() == DialogResult.OK)
{
   //Get the file's path
   var filePath = res.FileName;
   //Do something
   ....
}

完整的c#解决方案在这里:

private void btnSelectImage_Click(object sender, RoutedEventArgs e)
{
    // Configure open file dialog box 
    Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
    dlg.Filter = "";

    ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
    string sep = string.Empty;

    foreach (var c in codecs)
    {
       string codecName = c.CodecName.Substring(8).Replace("Codec", "Files").Trim();
       dlg.Filter = String.Format("{0}{1}{2} ({3})|{3}", dlg.Filter, sep, codecName, c.FilenameExtension);
       sep = "|";
    }

    dlg.Filter = String.Format("{0}{1}{2} ({3})|{3}", dlg.Filter, sep, "All Files", "*.*"); 

    dlg.DefaultExt = ".png"; // Default file extension 

    // Show open file dialog box 
    Nullable<bool> result = dlg.ShowDialog();

    // Process open file dialog box results 
    if (result == true)
    {
       // Open document 
       string fileName  = dlg.FileName;
       // Do something with fileName  
    }
} 

只是一个关于使用字符串的necrocomment。Join和LINQ。

ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
dlgOpenMockImage.Filter = string.Format("{0}| All image files ({1})|{1}|All files|*", 
    string.Join("|", codecs.Select(codec => 
    string.Format("{0} ({1})|{1}", codec.CodecName, codec.FilenameExtension)).ToArray()),
    string.Join(";", codecs.Select(codec => codec.FilenameExtension).ToArray()));

对于图像，您可以从GDI (System.Drawing)获得可用的编解码器，并通过一些工作来构建您的列表。这将是最灵活的方式。

ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

从文档中，你需要的过滤器语法如下:

Office Files|*.doc;*.xls;*.ppt

例如，图像文件|*.jpg;*.jpeg;*.png;....