C#5.0异步编程 HttpClient IP代理验证原码

//访问HttpClient 代码
public async Task<string> VerifyProxy(string
url, string proxy = "", string Method = "GET")
{

HttpClientHandler _hch = new HttpClientHandler()
{

Proxy = new WebProxy(proxy),
UseProxy = true

};
HttpClient _ch = new HttpClient(_hch);

try
{
sw.Start();
var
response = await _HttpClient.GetAsync(url);//, cancelationTokenSource.Token

sw.Stop();

response.EnsureSuccessStatusCode();//如果为false,则异常
if
(response.StatusCode == HttpStatusCode.OK)
{

return "true";
}

}
catch (Exception)
{

return "";
}
finally {
}

return "";
}

//显示代码

private void DisplayResults(int item, string result, decimal time)

{
dataGridView1.Rows[item].Cells[2].Value =
string.IsNullOrWhiteSpace(result) ? "失败" : "成功";

dataGridView1.Rows[item].Cells[3].Value = time;

}

//循环访问HTTPCLIENT
private async Task PageSizesAsync()

{
HttpClientHelper http = new HttpClientHelper();

Dictionary<string, int> protList = await SetProtList();

string result = string.Empty;
foreach (var item in
protList)
{
result = await
http.VerifyProxy(uri, item.Key);
DisplayResults(item.Value,
result, http.sw.ElapsedTicks / (decimal)Stopwatch.Frequency);
}

}