我有这个代码，我怎么能让它接受所有典型的图像格式?Png, jpeg, jpg, gif ?
以下是我目前所了解到的:
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，过滤器被设置为.txt文件。我可以更改为PNG，但其他类型呢?
当前回答
必须包含所有图像类型扩展名，并允许将所有文件作为一个选项。
所有文件|。|所有图片|.jpg;.jpeg;.png;.gif;.tif;.bmp|JPEG图片|.jpg|PNG图片|.png";
其他回答
我最喜欢汤姆·浮士德的回答。下面是他的解决方案的c#版本，但简化了一些事情。
var codecs = ImageCodecInfo.GetImageEncoders();
var codecFilter = "Image Files|";
foreach (var codec in codecs)
{
codecFilter += codec.FilenameExtension + ";";
}
dialog.Filter = codecFilter;
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();
下面是一个ImageCodecInfo建议的例子(在VB中):
Imports System.Drawing.Imaging
...
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", "*.*")
它是这样的:
使用此方法返回一个与Filter兼容的字符串，该字符串由支持当前系统理解的图像格式的ImageCodecInfo构建。
/// <summary>
/// Get the Filter string for all supported image types.
/// To be used in the FileDialog class Filter Property.
/// </summary>
/// <returns></returns>
public static string GetImageFilter()
{
string imageExtensions = string.Empty;
string separator = "";
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
Dictionary<string, string> imageFilters = new Dictionary<string, string>();
foreach (ImageCodecInfo codec in codecs)
{
imageExtensions = $"{imageExtensions}{separator}{codec.FilenameExtension.ToLower()}";
separator = ";";
imageFilters.Add($"{codec.FormatDescription} files ({codec.FilenameExtension.ToLower()})", codec.FilenameExtension.ToLower());
}
string result = string.Empty;
separator = "";
foreach (KeyValuePair<string, string> filter in imageFilters)
{
result += $"{separator}{filter.Key}|{filter.Value}";
separator = "|";
}
if (!string.IsNullOrEmpty(imageExtensions))
{
result += $"{separator}Image files|{imageExtensions}";
}
return result;
}
结果如下所示:
