Charger une image à partir d'une url dans une PictureBox

Essayez ceci:

var request = WebRequest.Create("http://www.gravatar.com/avatar/6810d91caff032b202c50701dd3af745?d=identicon&r=PG");

using (var response = request.GetResponse())
using (var stream = response.GetResponseStream())
{
    pictureBox1.Image = Bitmap.FromStream(stream);
}

Voici la solution que j'utilise. Je ne me souviens pas pourquoi je ne pourrais pas simplement utiliser le contrôle PictureBox.Charger des méthodes. Je suis sûr que c'est parce que je voulais correctement l'échelle & centre de l'image téléchargée dans le contrôle PictureBox. Si je me souviens bien, toutes les options d'échelle sur la PictureBox soit étirer l'image, ou pour redimensionner la PictureBox pour ajuster l'image. Je voulais correctement mis à l'échelle et à centrer l'image dans la taille que j'ai mis pour le contrôle PictureBox.

Maintenant, j'ai juste besoin de faire une version asynchrone...

Voici mes méthodes:

   #region Image Utilities
///<summary>
///Loads an image from a URL into a Bitmap object.
///Currently as written if there is an error during downloading of the image, no exception is thrown.
///</summary>
///<param name="url"></param>
///<returns></returns>
public static Bitmap LoadPicture(string url)
{
System.Net.HttpWebRequest wreq;
System.Net.HttpWebResponse wresp;
Stream mystream;
Bitmap bmp;
bmp = null;
mystream = null;
wresp = null;
try
{
wreq = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(url);
wreq.AllowWriteStreamBuffering = true;
wresp = (System.Net.HttpWebResponse)wreq.GetResponse();
if ((mystream = wresp.GetResponseStream()) != null)
bmp = new Bitmap(mystream);
}
catch
{
//Do nothing... 
}
finally
{
if (mystream != null)
mystream.Close();
if (wresp != null)
wresp.Close();
}
return (bmp);
}
///<summary>
///Takes in an image, scales it maintaining the proper aspect ratio of the image such it fits in the PictureBox's canvas size and loads the image into picture box.
///Has an optional param to center the image in the picture box if it's smaller then canvas size.
///</summary>
///<param name="image">The Image you want to load, see LoadPicture</param>
///<param name="canvas">The canvas you want the picture to load into</param>
///<param name="centerImage"></param>
///<returns></returns>
public static Image ResizeImage(Image image, PictureBox canvas, bool centerImage ) 
{
if (image == null || canvas == null)
{
return null;
}
int canvasWidth = canvas.Size.Width;
int canvasHeight = canvas.Size.Height;
int originalWidth = image.Size.Width;
int originalHeight = image.Size.Height;
System.Drawing.Image thumbnail =
new Bitmap(canvasWidth, canvasHeight); //changed parm names
System.Drawing.Graphics graphic =
System.Drawing.Graphics.FromImage(thumbnail);
graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphic.SmoothingMode = SmoothingMode.HighQuality;
graphic.PixelOffsetMode = PixelOffsetMode.HighQuality;
graphic.CompositingQuality = CompositingQuality.HighQuality;
/* ------------------ new code --------------- */
//Figure out the ratio
double ratioX = (double)canvasWidth / (double)originalWidth;
double ratioY = (double)canvasHeight / (double)originalHeight;
double ratio = ratioX < ratioY ? ratioX : ratioY; //use whichever multiplier is smaller
//now we can get the new height and width
int newHeight = Convert.ToInt32(originalHeight * ratio);
int newWidth = Convert.ToInt32(originalWidth * ratio);
//Now calculate the X,Y position of the upper-left corner 
//(one of these will always be zero)
int posX = Convert.ToInt32((canvasWidth - (image.Width * ratio)) / 2);
int posY = Convert.ToInt32((canvasHeight - (image.Height * ratio)) / 2);
if (!centerImage)
{
posX = 0;
posY = 0;
}
graphic.Clear(Color.White); //white padding
graphic.DrawImage(image, posX, posY, newWidth, newHeight);
/* ------------- end new code ---------------- */
System.Drawing.Imaging.ImageCodecInfo[] info =
ImageCodecInfo.GetImageEncoders();
EncoderParameters encoderParameters;
encoderParameters = new EncoderParameters(1);
encoderParameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality,
100L);
Stream s = new System.IO.MemoryStream();
thumbnail.Save(s, info[1],
encoderParameters);
return Image.FromStream(s);
}
#endregion

Voici le nécessaire comprend. (Certains pourraient être nécessaires par un autre code, mais y compris tous pour être sûr)

using System.Windows.Forms;
using System.Drawing.Drawing2D;
using System.IO;
using System.Drawing.Imaging;
using System.Text.RegularExpressions;
using System.Drawing;

Comment je l'utilise généralement:

 ImageUtil.ResizeImage(ImageUtil.LoadPicture( "http://someurl/img.jpg", pictureBox1, true);