[英]C# Downloading a zip file from url based on input params
我有一個要求,我必須根據輸入參數從服務器使用c#下載zip文件(大小可以在10mb-400mb之間變化)。 例如,下載userId = 10和year = 2012的報告。
Web服務器接受這兩個參數並返回一個zip文件。 如何使用WebClient類實現此目的?
謝謝
您可以通過擴展WebClient類來實現
class ExtWebClient : WebClient
{
public NameValueCollection PostParam { get; set; }
protected override WebRequest GetWebRequest(Uri address)
{
WebRequest tmprequest = base.GetWebRequest(address);
HttpWebRequest request = tmprequest as HttpWebRequest;
if (request != null && PostParam != null && PostParam.Count > 0)
{
StringBuilder postBuilder = new StringBuilder();
request.Method = "POST";
//build the post string
for (int i = 0; i < PostParam.Count; i++)
{
postBuilder.AppendFormat("{0}={1}", Uri.EscapeDataString(PostParam.GetKey(i)),
Uri.EscapeDataString(PostParam.Get(i)));
if (i < PostParam.Count - 1)
{
postBuilder.Append("&");
}
}
byte[] postBytes = Encoding.ASCII.GetBytes(postBuilder.ToString());
request.ContentLength = postBytes.Length;
request.ContentType = "application/x-www-form-urlencoded";
var stream = request.GetRequestStream();
stream.Write(postBytes, 0, postBytes.Length);
stream.Close();
stream.Dispose();
}
return tmprequest;
}
}
用法:如果您必須創建POST類型的請求
class Program
{
private static void Main()
{
ExtWebClient webclient = new ExtWebClient();
webclient.PostParam = new NameValueCollection();
webclient.PostParam["param1"] = "value1";
webclient.PostParam["param2"] = "value2";
webclient.DownloadFile("http://www.example.com/myfile.zip", @"C:\myfile.zip");
}
}
用法:對於GET類型請求,您可以簡單地使用Normal webclient
class Program
{
private static void Main()
{
WebClient webclient = new WebClient();
webclient.DownloadFile("http://www.example.com/myfile.zip?param1=value1¶m2=value2", @"C:\myfile.zip");
}
}
string url = @"http://www.microsoft.com/windows8.zip";
WebClient client = new WebClient();
client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);
client.DownloadFileAsync(new Uri(url), @"c:\windows\windows8.zip");
void client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
MessageBox.Show("File downloaded");
}
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