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
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;
其他回答
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;....
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:
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()));
为了匹配一个由不同类别的文件组成的列表，你可以像这样使用过滤器:
var dlg = new Microsoft.Win32.OpenFileDialog()
{
DefaultExt = ".xlsx",
Filter = "Excel Files (*.xls, *.xlsx)|*.xls;*.xlsx|CSV Files (*.csv)|*.csv"
};
对于那些不想每次都记住语法的人，这里有一个简单的封装:
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();
