c＃如果等待url.getstringasync null，如何重试

Question

我想问一下如何重试 await url.GetStringAsync获得取消任务？

ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
var httpclient = new HttpClient();
var html = await httpclient.GetStringAsync(url);

Answer 1

如果您想在上面的代码中这样做（而不是使用HttpResponse对象）那么您可以做以下

之类的事情

ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
var httpclient = new HttpClient();
int retries = 5;
int count = 0;
var html = await httpclient.GetStringAsync(url);
while(String.IsNullOrEmpty(html) && count++ < retries) {
    var html = await httpclient.GetStringAsync(url); }
if(String.IsNullOrEmpty(html)) {
    throw new Exception("Could not contact the server"); }