. Net C # Check whether the remote URL exists

Three methods are used to check whether a remote URL exists.

 

Private void page_load (Object sender, system. eventargs E)

{

String url1 = "http://www.ximenyifan.com /";

String url2 ="

Response. Write ("<li> Method 1 :");

Response. Write (url1 + ":" + urlexistsusinghttpwebrequest (url1). tostring ());

Response. Write ("<li> Method 2 :");

Response. Write (url1 + "exist:" + urlexistsusingsockets (url1). tostring ());

Response. Write ("<li> method 3 :");

Response. Write (url1 + "exist:" + urlexistsusingxmlhttp (url1). tostring ());

Response. Write ("<li> Method 1 :");

Response. Write (url2 + ":" + urlexistsusinghttpwebrequest (url2). tostring ());

Response. Write ("<li> method 3 :");

Response. Write (url2 + "exist:" + urlexistsusingxmlhttp (url2). tostring ());

}

Private bool urlexistsusinghttpwebrequest (string URL ){

Try

{

System. net. httpwebrequest myrequest = (system. net. httpwebrequest) system. net. webrequest. Create (URL );

Myrequest. method = "head ";

MySQL request. Timeout = 100;

System. net. httpwebresponse res = (system. net. httpwebresponse) myrequest. getresponse ();

Return (res. statuscode = system. net. httpstatuscode. OK );

}

Catch (system. net. webexception we)

{

System. Diagnostics. Trace. Write (We. Message );

Return false;

}

}

Private bool urlexistsusingxmlhttp (string URL)

{

// Note: msxml2.dll must be referenced in this method.

Msxml2.xmlhttp _ XMLHTTP = new msxml2.xmlhttpclass ();

_ XMLHTTP. Open ("head", URL, false, null, null );

_ XMLHTTP. Send ("");

Return (_ XMLHTTP. Status = 200 );

}

Private bool urlexistsusingsockets (string URL)

{

If (URL. startswith ("http: //") url = URL. Remove (0, "http: //". Length );

Try

{

System. net. iphostentry iphost = system. net. DNS. Resolve (URL );

Return true;

}

Catch (system. net. sockets. socketexception SE)

{

System. Diagnostics. Trace. Write (SE. Message );

Return false;

}

}