Update configure-ssl-certificate-in-code.md

Author: abatishchev

articles/app-service/configure-ssl-certificate-in-code.md

@@ -54,25 +54,29 @@ In C# code, you access the certificate by the certificate thumbprint. The follow
 
 ```csharp
 using System;
+using System.Linq;
 using System.Security.Cryptography.X509Certificates;
 
-...
-X509Store certStore = new X509Store(StoreName.My, StoreLocation.CurrentUser);
-certStore.Open(OpenFlags.ReadOnly);
-X509Certificate2Collection certCollection = certStore.Certificates.Find(
-                            X509FindType.FindByThumbprint,
-                            // Replace below with your certificate's thumbprint
-                            "E661583E8FABEF4C0BEF694CBC41C28FB81CD870",
-                            false);
-// Get the first cert with the thumbprint
-if (certCollection.Count > 0)
+string certThumbprint = "E661583E8FABEF4C0BEF694CBC41C28FB81CD870";
+
+using (X509Store certStore = new X509Store(StoreName.My, StoreLocation.CurrentUser))
 {
-    X509Certificate2 cert = certCollection[0];
-    // Use certificate
-    Console.WriteLine(cert.FriendlyName);
+  certStore.Open(OpenFlags.ReadOnly);
+
+  X509Certificate2Collection certCollection = certStore.Certificates.Find(
+                              X509FindType.FindByThumbprint,
+                              // Replace below with your certificate's thumbprint
+                              certThumbprint,
+                              false);
+  // Get the first cert with the thumbprint
+  X509Certificate2 cert = certCollection.OfType<X509Certificate>().FirstOrDefault();
+
+  if (cert is null)
+      throw new Exception($"Certificate with thumbprint {certThumbprint} was not found");
+
+  // Use certificate
+  Console.WriteLine(cert.FriendlyName);
 }
-certStore.Close();
-...
 ```
 
 In Java code, you access the certificate from the "Windows-MY" store using the Subject Common Name field (see [Public key certificate](https://en.wikipedia.org/wiki/Public_key_certificate)). The following code shows how to load a private key certificate: