var s = "Username=sample@aaa.xom&Password=qwerasdf";
        var u = "https://designalist.net/umbraco/Surface/Membership/ApiLogin";
        NSMutableUrlRequest request = new NSMutableUrlRequest(NSUrl.FromString(u));
        // var b = new NSString();
        request.Body = NSData.FromString(s, NSStringEncoding.UTF8);
        request.HttpMethod = "POST";
        webView.LoadRequest(request);

String postData = "Username=sample@aaa.com&Password=qwerasdf";
        try {
            WebSettings webSettings = webView.getSettings();
            webSettings.setJavaScriptEnabled(true);
            webView.postUrl("https://designalist.net/umbraco/Surface/Membership/ApiLogin", EncodingUtils.getBytes(postData, "UTF-8"));
        } catch (Exception exp) {
            exp.printStackTrace();
        }