From c8de370195d17fe551b7fd4f741bdf8610babb81 Mon Sep 17 00:00:00 2001
From: sta <sta.blockhead@gmail.com>
Date: Tue, 18 Aug 2020 21:19:38 +0900
Subject: [PATCH] [Modify] Polish it

---
 websocket-sharp/Net/HttpListenerPrefixCollection.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/websocket-sharp/Net/HttpListenerPrefixCollection.cs b/websocket-sharp/Net/HttpListenerPrefixCollection.cs
index 4a725704..1e585194 100644
--- a/websocket-sharp/Net/HttpListenerPrefixCollection.cs
+++ b/websocket-sharp/Net/HttpListenerPrefixCollection.cs
@@ -190,10 +190,11 @@ namespace WebSocketSharp.Net
     /// </exception>
     public bool Contains (string uriPrefix)
     {
-      _listener.CheckDisposed ();
       if (uriPrefix == null)
         throw new ArgumentNullException ("uriPrefix");
 
+      _listener.CheckDisposed ();
+
       return _prefixes.Contains (uriPrefix);
     }