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?
写出应用程序需要的类型。(ref FileDialog.Filter)。以下是最常见的图像格式。
private static string GetImageFilter()
{
return
"All Files (*.*)|*.*" +
"|All Pictures (*.emf;*.wmf;*.jpg;*.jpeg;*.jfif;*.jpe;*.png;*.bmp;*.dib;*.rle;*.gif;*.emz;*.wmz;*.tif;*.tiff;*.svg;*.ico)" +
"|*.emf;*.wmf;*.jpg;*.jpeg;*.jfif;*.jpe;*.png;*.bmp;*.dib;*.rle;*.gif;*.emz;*.wmz;*.tif;*.tiff;*.svg;*.ico" +
"|Windows Enhanced Metafile (*.emf)|*.emf" +
"|Windows Metafile (*.wmf)|*.wmf" +
"|JPEG File Interchange Format (*.jpg;*.jpeg;*.jfif;*.jpe)|*.jpg;*.jpeg;*.jfif;*.jpe" +
"|Portable Network Graphics (*.png)|*.png" +
"|Bitmap Image File (*.bmp;*.dib;*.rle)|*.bmp;*.dib;*.rle" +
"|Compressed Windows Enhanced Metafile (*.emz)|*.emz" +
"|Compressed Windows MetaFile (*.wmz)|*.wmz" +
"|Tag Image File Format (*.tif;*.tiff)|*.tif;*.tiff" +
"|Scalable Vector Graphics (*.svg)|*.svg" +
"|Icon (*.ico)|*.ico";
}
示例使用
设置FilterIndex = 2以预选“所有图片”。不要设置openFileDialog。除非你有一个很好的理由。
void OpenImageFile()
{
var openFileDialog = new OpenFileDialog
{
Filter = GetImageFilter(),
FilterIndex = 2,
RestoreDirectory = true
};
DialogResult result = openFileDialog.ShowDialog();
// do something with your file
// bool resultOk = (result == System.Windows.Forms.DialogResult.OK);
// string filePath = openFileDialog.FileName;
// ...
}
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
}
}
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: