/// <summary>
/// Gets an image by the specified uniform resource identifier (URI) asynchronously.
/// </summary>
/// <param name="uri">A uniform resource identifier (URI) to the image.</param>
/// <param name="callback">
/// This method will be called when the downloading operation completed.
/// </param>
/// <exception cref="System.UriFormatException"/>
public void GetImageAsync(string uri, AsyncImageCallback callback)
{
if (!Uri.IsWellFormedUriString(uri, UriKind.Absolute))
{
throw new UriFormatException();
}
Uri imageUri;
var temp = Uri.TryCreate(uri, UriKind.Absolute, out imageUri);
if (!temp)
{
throw new UriFormatException();
}
var fileName = imageUri.Segments.Last();
var fileFullName = Path.Combine(path, fileName);
if (memoryCache.ContainsKey(fileName))
{
callback(memoryCache[fileName].Clone() as Image);
return;
}
var token = fileFullName.GetHashCode();
if (callbacks.ContainsKey(token))
{
callbacks[token].Add(callback);
}
else
{
callbacks.Add(token, new List <AsyncImageCallback> {
callback
});
}
try
{
foreach (var client in clients.Where(c => !c.IsBusy))
{
client.DownloadFileAsync(imageUri, fileFullName, fileFullName);
return;
}
var newClient = new WebClient();
newClient.DownloadFileCompleted += client_DownloadFileCompleted;
clients.Enqueue(newClient);
newClient.DownloadFileAsync(imageUri, fileFullName, fileFullName);
}
catch (WebException)
{
callbacks.Remove(token);
}
}
/// <summary>
/// Gets an image by the specified uniform resource identifier (URI) asynchronously.
/// </summary>
/// <param name="uri">A uniform resource identifier (URI) to the image.</param>
/// <param name="callback">
/// This method will be called when the downloading operation completed.
/// </param>
/// <exception cref="System.UriFormatException"/>
public void GetImageAsync(string uri, AsyncImageCallback callback)
{
if (!Uri.IsWellFormedUriString(uri, UriKind.Absolute))
throw new UriFormatException();
Uri imageUri;
var temp = Uri.TryCreate(uri, UriKind.Absolute, out imageUri);
if (!temp) throw new UriFormatException();
var fileName = imageUri.Segments.Last();
var fileFullName = Path.Combine(path, fileName);
if (memoryCache.ContainsKey(fileName))
{
callback(memoryCache[fileName].Clone() as Image);
return;
}
var token = fileFullName.GetHashCode();
if (callbacks.ContainsKey(token))
callbacks[token].Add(callback);
else
callbacks.Add(token, new List<AsyncImageCallback> { callback });
try
{
foreach (var client in clients.Where(c => !c.IsBusy))
{
client.DownloadFileAsync(imageUri, fileFullName, fileFullName);
return;
}
var newClient = new WebClient();
newClient.DownloadFileCompleted += client_DownloadFileCompleted;
clients.Enqueue(newClient);
newClient.DownloadFileAsync(imageUri, fileFullName, fileFullName);
}
catch (WebException)
{
callbacks.Remove(token);
}
}
