c# - 如何检查 URL 是否有效

Question

我在该用户中有一个文本框输入 URL，但是如果想在页面呈现时检查该 URL，那么该怎么办？

这是我的代码：

protected void btnRender_Click(object sender, EventArgs e)
{
    string strResult = string.Empty;
    WebResponse objResponse;
    WebRequest objRequest = System.Net.HttpWebRequest.Create(urltxt.Text);
    objResponse = objRequest.GetResponse();
    using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
    {
        strResult = sr.ReadToEnd();
        sr.Close();
    }
    strResult = strResult.Replace("<form id='form1' method='post' action=''>", "");
    strResult = strResult.Replace("</form>", "");          
    TextBox1.Text = strResult.Trim();
    div.InnerHtml = strResult.Trim();
}

我有这个代码来检查 URL 是否有效，所以你能告诉我在哪里调用它吗？{如果我还想检查 https 那么我该怎么做这个代码}

 protected bool CheckUrlExists(string url)
    {
        // If the url does not contain Http. Add it.
      // if i want to also check for https how can i do.this code is only for http not https
        if (!url.Contains("http://"))
        {
            url = "http://" + url;
        }
        try
        {
            var request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "HEAD";
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                return response.StatusCode == HttpStatusCode.OK;
            }
         }
         catch
         {
             return false;
         }
     }

文本框名称是 urltxt

Answer 1

试试下面的方法，它会帮助你....

     protected void btnRender_Click(object sender, EventArgs e)
        {
            if(CheckUrlExists(urltxt.Text))
            {
                string strResult = string.Empty;
                WebResponse objResponse;
                WebRequest objRequest = System.Net.HttpWebRequest.Create(urltxt.Text);
                objResponse = objRequest.GetResponse();
                using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
                {
                    strResult = sr.ReadToEnd();
                    sr.Close();
                }
                strResult = strResult.Replace("<form id='form1' method='post' action=''>", "");
                strResult = strResult.Replace("</form>", "");
                TextBox1.Text = strResult.Trim();
                div.InnerHtml = strResult.Trim();
            }
            else
            {
                MessageBox.Show("Not a Valid URL");
            }
        }

Answer 2

试试这个 uriName（你想要的 URI）

  bool Uriresult = Uri.TryCreate(uriName, UriKind.Absolute, out uriResult) && uriName.Scheme == Uri.UriSchemeHttp;

根据您的代码

string uriName = urltxt.Text; bool Uriresult = Uri.TryCreate(uriName, UriKind.Absolute, out uriResult) && uriName.Scheme == Uri.UriSchemeHttp;