From 40242360000e9830ff139ebfaaa52d24686f5c68 Mon Sep 17 00:00:00 2001
From: Aigio Liu <lysoft.pw@foxmail.com>
Date: Wed, 3 Mar 2021 20:52:15 +0800
Subject: [PATCH] fix

---
 .../Extensions/ViewModelExtensions.cs                        | 5 +++++
 .../FileSystemDesktop.cs                                     | 3 +--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/System.Application.SteamTools.Client.Desktop/Extensions/ViewModelExtensions.cs b/System.Application.SteamTools.Client.Desktop/Extensions/ViewModelExtensions.cs
index 6db13e749..a3c38610e 100644
--- a/System.Application.SteamTools.Client.Desktop/Extensions/ViewModelExtensions.cs
+++ b/System.Application.SteamTools.Client.Desktop/Extensions/ViewModelExtensions.cs
@@ -15,6 +15,11 @@ namespace System.Application
                 return disposable;
             }
 
+            if (vm.CompositeDisposable == null)
+            {
+                throw new ArgumentNullException(nameof(ViewModelBase.CompositeDisposable));
+            }
+
             vm.CompositeDisposable.Add(disposable);
             return disposable;
         }
diff --git a/System.Application.SteamTools.Client.Desktop/FileSystemDesktop.cs b/System.Application.SteamTools.Client.Desktop/FileSystemDesktop.cs
index cfab10cd3..c93aa9f76 100644
--- a/System.Application.SteamTools.Client.Desktop/FileSystemDesktop.cs
+++ b/System.Application.SteamTools.Client.Desktop/FileSystemDesktop.cs
@@ -1,5 +1,4 @@
-using System.Application.UI;
-using System.IO;
+using System.IO;
 
 namespace System.Application
 {