从url加载图像到一个图片框

I want to load an image into a PictureBox. This is the image I want to load: http://www.gravatar.com/avatar/6810d91caff032b202c50701dd3af745?d=identicon&r=PG

我想把一个图像加载到一个图片框中。这是我要加载的图像:http://www.gravatar.com/avatar/6810d91caff032b202c50701dd3af745?

How do I do this?

我该怎么做呢?

4 个解决方案

#1

The inbuilt PictureBox.Load(string URL) Method "sets the ImageLocation to the specified URL and displays the image indicated." (Since .NetFramework 2)

内置图片框。Load(string URL)方法“将ImageLocation设置为指定的URL并显示所指示的图像。”(因为.NetFramework 2)

#2

Try this:

试试这个:

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);
}

#3

yourPictureBox.ImageLocation = "http://www.gravatar.com/avatar/6810d91caff032b202c50701dd3af745?d=identicon&r=PG"

#4

Here's the solution I use. I can't remember why I couldn't just use the PictureBox.Load methods. I'm pretty sure it's because I wanted to properly scale & center the downloaded image into the PictureBox control. If I recall, all the scaling options on PictureBox either stretch the image, or will resize the PictureBox to fit the image. I wanted a properly scaled and centered image in the size I set for PictureBox.

这是我用的方法。我不记得为什么我不能用那个图片框。加载方法。我很确定这是因为我想把下载的图像适当地缩放到图片框控件中。如果我记得的话，在PictureBox上的所有缩放选项要么是拉伸了图像，要么是调整了PictureBox的大小以适应图像。我想要一个适当的缩放和居中的图像在我为图片框设置的大小。

Now, I just need to make a async version...

现在，我只需要创建一个异步版本……

Here's my methods:

这是我的方法:

   #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

Here's the required includes. (Some might be needed by other code, but including all to be safe)

这是所需的包括。(其他代码可能需要一些代码，但为了安全起见，包括所有代码)

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

How I generally use it:

我通常如何使用它:

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