將篩選器設置爲OpenFileDialog以允許使用典型的圖像格式？

Question

我有這段代碼，我該如何讓它接受所有典型的圖像格式？ PNG，JPEG，JPG，GIF？

這是我到目前爲止有：

public void EncryptFile() 
{    
    OpenFileDialog dialog = new OpenFileDialog(); 
    dialog.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"; 
    dialog.InitialDirectory = @"C:\"; 
    dialog.Title = "Please select an image file to encrypt."; 

    if (dialog.ShowDialog() == DialogResult.OK) 
    { 
     //Encrypt the selected file. I'll do this later. :) 
    }    
} 

注意這個過濾器設置爲.txt文件。我可能更改爲PNG，但其他類型？

Answer 1

從the docs，你需要的過濾器語法如下：

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

即多個擴展用分號分隔 - 因此，Image Files|*.jpg;*.jpeg;*.png;...。

Answer 2

對於圖像，您可以從GDI（System.Drawing）獲得可用的編解碼器，並通過一些工作構建您的列表。這將是最靈活的方式。

ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders(); 

Answer 3

這裏的ImageCodecInfo建議（以VB）的例子：

 Dim ofd as new OpenFileDialog() 
     ofd.Filter = "" 
     Dim codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders() 
     Dim sep As String = String.Empty 
     For Each c As ImageCodecInfo In codecs 
      Dim codecName As String = c.CodecName.Substring(8).Replace("Codec", "Files").Trim() 
      ofd.Filter = String.Format("{0}{1}{2} ({3})|{3}", ofd.Filter, sep, codecName, c.FilenameExtension) 
      sep = "|" 
     Next 
     ofd.Filter = String.Format("{0}{1}{2} ({3})|{3}", ofd.Filter, sep, "All Files", "*.*") 

它看起來是這樣的：

Answer 4

在C＃完整的解決方案是在這裏：

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 
    } 
} 

Answer 5

遵循這個模式，如果你瀏覽的圖像文件：

dialog.Filter = "Image files (*.jpg, *.jpeg, *.jpe, *.jfif, *.png) | *.jpg; *.jpeg; *.jpe; *.jfif; *.png"; 

Answer 6

要過濾的圖像文件，請使用此代碼示例。

//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 
    .... 
} 

Answer 7

只是使用string.Join和LINQ的necrocomment。

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())); 

Answer 8

對於那些不想在這裏記住語法每次誰是一個簡單的封裝：

public class FileDialogFilter : List<string> 
{ 
    public string Explanation { get; } 

    public FileDialogFilter(string explanation, params string[] extensions) 
    { 
     Explanation = explanation; 
     AddRange(extensions); 
    } 

    public string GetFileDialogRepresentation() 
    { 
     if (!this.Any()) 
     { 
      throw new ArgumentException("No file extension is defined."); 
     } 

     StringBuilder builder = new StringBuilder(); 

     builder.Append(Explanation); 

     builder.Append(" ("); 
     builder.Append(String.Join(", ", this)); 
     builder.Append(")"); 

     builder.Append("|"); 
     builder.Append(String.Join(";", this)); 

     return builder.ToString(); 
    } 
} 

public class FileDialogFilterCollection : List<FileDialogFilter> 
{ 
    public string GetFileDialogRepresentation() 
    { 
     return String.Join("|", this.Select(filter => filter.GetFileDialogRepresentation())); 
    } 
} 

用法：

FileDialogFilter filterImage = new FileDialogFilter("Image Files", "*.jpeg", "*.bmp"); 
FileDialogFilter filterOffice = new FileDialogFilter("Office Files", "*.doc", "*.xls", "*.ppt"); 

FileDialogFilterCollection filters = new FileDialogFilterCollection 
{ 
    filterImage, 
    filterOffice 
}; 

OpenFileDialog fileDialog = new OpenFileDialog 
{ 
    Filter = filters.GetFileDialogRepresentation() 
}; 

fileDialog.ShowDialog(); 

Answer 9

我喜歡湯姆·福斯特的回答是最好的。這是他的解決方案的C＃版本，但簡化了一些事情。

var codecs = ImageCodecInfo.GetImageEncoders(); 
var codecFilter = "Image Files|"; 
foreach (var codec in codecs) 
{ 
    codecFilter += codec.FilenameExtension + ";"; 
} 
dialog.Filter = codecFilter; 

Answer 10

這是極端，但是我建立一個名爲FILE_TYPES 2列的數據庫表中的動態，數據庫驅動的過濾器，用字段名的延伸和DOCTYPE：

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

很顯然，我有很多不同類型的和擴展，但我正在簡化它的例子。這裏是我的功能：

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]; 
      ... 

應該產生一個過濾器，看起來像這樣：

Answer 11

爲了匹配不同類別的文件的列表，你可以使用過濾器是這樣的：

 var dlg = new Microsoft.Win32.OpenFileDialog() 
     { 
      DefaultExt = ".xlsx", 
      Filter = "Excel Files (*.xls, *.xlsx)|*.xls;*.xlsx|CSV Files (*.csv)|*.csv" 
     };