<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="vertical"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:background="#fff">

    <ImageView

        android:id="@+id/showPic"

        android:layout_width="400px"

        android:layout_height="400px" />

</LinearLayout>

using System;

using System.IO;

using System.Net;

using Android.App;

using Android.Content;

using Android.Graphics.Drawables;

using Android.Runtime;

using Android.Views;

using Android.Widget;

using Android.OS;

namespace LoadPic

{

    [Activity(Label = "LoadPic", MainLauncher = true)]

    public class MainActivity : Activity

    {

        private ImageView showPic;

        private string picPath = "http://www.kl.cc/images/about/tizi/jiangkun/inscription-jiangkun.jpg";

        ProgressDialog msgbox;

        protected override void OnCreate(Bundle bundle)

        {

            base.OnCreate(bundle);

            SetContentView(Resource.Layout.Main);

            showPic = FindViewById<ImageView>(Resource.Id.showPic);

            msgbox = ProgressDialog.Show(this, "请稍等", "图片正在加载中...", true, true);

            HttpWebRequest req = WebRequest.Create(picPath) as HttpWebRequest;

            req.Method = "Get";

            req.GetResponseAsync().ContinueWith(o =>

            {

                HttpWebResponse resp = (HttpWebResponse)o.Result;

                this.RunOnUiThread(() =>

                {

                    Drawable dr = new BitmapDrawable(resp.GetResponseStream());

                    showPic.SetImageDrawable(dr);

                    msgbox.Cancel();

                });

            });

        }

    }

}