GetImageSynchronous
(
String uriString
)
{
Debug.Assert(!String.IsNullOrEmpty(uriString));
AssertValid();
const Int32 ErrorImageWidthAndHeight = 52;
Uri oUri;
if (Uri.TryCreate(uriString, UriKind.Absolute, out oUri))
{
if (oUri.Scheme == Uri.UriSchemeHttp ||
oUri.Scheme == Uri.UriSchemeHttps)
{
try
{
return(GetImageSynchronousHttp(oUri));
}
catch (WebException)
{
// (These empty catch blocks cause an error image to be
// returned.)
}
catch (ArgumentException)
{
/*
* Attempting to download a possibly corrupt image from this
* Twitter URL:
*
* http://a1.twimg.com/profile_images/1112245377/
* Photo_on_2010-08-27_at_18.51_normal.jpg
*
* raised the following exception:
*
* [ArgumentException]: An invalid character was found in text
* content.
* at System.Windows.Media.Imaging.BitmapFrameDecode.
* get_ColorContexts()
* at System.Windows.Media.Imaging.BitmapImage.
* FinalizeCreation()
* at System.Windows.Media.Imaging.BitmapImage.EndInit()
*/
}
catch (FileFormatException)
{
/*
* A user attempted to download a possibly corrupt image from
* Twitter on 5/6/2011. The exact URL wasn't determined.
*
* The following exception was raised:
*
* [FileFormatException]: The image format is unrecognized.
* [COMException]: Exception from HRESULT: 0x88982F07 at
* System.Windows.Media.Imaging.BitmapDecoder.
* SetupDecoderFromUriOrStream(Uri uri, Stream stream,
* BitmapCacheOption cacheOption, Guid& clsId, Boolean&
* isOriginalWritable, Stream& uriStream,
* UnmanagedMemoryStream& unmanagedMemoryStream,
* SafeFileHandle& safeFilehandle)
*/
}
catch (IOException)
{
/*
* Attempting to download a possibly corrupt image from this
* Twitter URL:
*
* http://a2.twimg.com/profile_images/1126755034/
* 8FjbVD_normal.gif
*
* raised the following exception:
*
* [IOException]: Cannot read from the stream.
* [COMException]: Exception from HRESULT: 0x88982F72
* at System.Windows.Media.Imaging.BitmapDecoder.
* SetupDecoderFromUriOrStream(Uri uri, Stream stream,
* BitmapCacheOption cacheOption, Guid& clsId, Boolean&
* isOriginalWritable, Stream& uriStream,
* UnmanagedMemoryStream& unmanagedMemoryStream,
* SafeFileHandle& safeFilehandle)
* ...
*/
}
catch (NotSupportedException)
{
/*
* Attempting to download a possibly corrupt image from a
* Twitter URL (didn't record the URL) raised the following
* exception:
*
* [NotSupportedException]: No imaging component suitable
* to complete this operation was found.
*/
}
}
else if (oUri.Scheme == Uri.UriSchemeFile)
{
try
{
// This is a synchronous operation.
BitmapImage oBitmapImage = new BitmapImage(oUri);
WpfGraphicsUtil.FreezeIfFreezable(oBitmapImage);
return(oBitmapImage);
}
catch (IOException)
{
}
catch (ArgumentException)
{
// This occurs when the URI contains an invalid character,
// such as "<".
}
catch (WebException)
{
// This occurs when a non-existent drive letter is used.
}
catch (NotSupportedException)
{
// Invalid image file.
}
catch (UnauthorizedAccessException)
{
// The URI is actually a folder, for example.
}
}
}
if (m_oCachedErrorImage == null)
{
m_oCachedErrorImage = CreateErrorImage(ErrorImageWidthAndHeight);
}
return(m_oCachedErrorImage);
}