c# 下载网页图片

要下载图片首先要有图片地址

要有图片地址就要先把网页下下来分析下URL

下载网页一般用两种方法

1，用 system.net.webclient

using System.Net;

using System.Windows.Forms;

string url = "http://www.cnblogs.com";

string result = null;

try

{

WebClient client = new WebClient();

result = client.DownloadString( url );

}

catch (Exception ex)

{

MessageBox.Show( ex.Message );

}

2,用 System.Net.HttpWebRequest

using System.Net;

using System.IO;

using System.Windows.Forms;

string result = null;

string url = "http://www.cnblogs.com";

WebResponse response = null;

StreamReader reader = null;

try

{

HttpWebRequest request = (HttpWebRequest)WebRequest.Create( url );

request.Method = "GET";

response = request.GetResponse();

reader = new StreamReader( response.GetResponseStream(), Encoding.UTF8 );

result = reader.ReadToEnd();

}

catch (Exception ex)

{

MessageBox.Show( ex.Message );

}

finally

{

if (reader != null)

reader.Close();

if (response != null)

response.Close();

}

至于怎么找图片url略过，直接说下载图片吧

其实和上面一样，也有两种方法：

1，WebRequest和WebResponse

WebRequest request = WebRequest.Create("http://images.cnblogs.com/logo_small.gif");

WebResponse response = request.GetResponse();

Stream reader = response.GetResponseStream();

FileStream writer = new FileStream("x:\\pic.jpg", FileMode.OpenOrCreate, FileAccess.Write);

byte[] buff = new byte[512];

int c = 0; //实际读取的字节数

while ((c=reader.Read(buff, 0, buff.Length)) > 0)

{

writer.Write(buff, 0, c);

}

writer.Close();

writer.Dispose();

reader.Close();

reader.Dispose();

response.Close();

2,WebClient

string url = "http://images.cnblogs.com/logo_small.gif";

string filepath = "x:\\pic.jpg";

WebClient mywebclient = new WebClient();

mywebclient.DownloadFile(url, filepath);