From 97010069a2f2c3475b2b434b1c9dfaa17aaee899 Mon Sep 17 00:00:00 2001
From: Rich Bryant <rich.bryant@live.co.uk>
Date: Fri, 17 Jan 2020 22:17:53 +0000
Subject: [PATCH] Fix to stop blazor crash (#2318)

* Update ReactiveComponentBase.cs

* Added @limefrogyank's fix, reverted variable name

* Changes to enable testing

* reverted proj file now tested

* Changed back to indented in both files

* Reverted ordering and variable name
---
 src/ReactiveUI.Blazor/ReactiveComponentBase.cs       | 4 +---
 src/ReactiveUI.Blazor/ReactiveLayoutComponentBase.cs | 2 +-
 src/ReactiveUI.Blazor/ReactiveUI.Blazor.csproj       | 2 +-
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/ReactiveUI.Blazor/ReactiveComponentBase.cs b/src/ReactiveUI.Blazor/ReactiveComponentBase.cs
index f8ef575029..b6e609879f 100644
--- a/src/ReactiveUI.Blazor/ReactiveComponentBase.cs
+++ b/src/ReactiveUI.Blazor/ReactiveComponentBase.cs
@@ -7,12 +7,10 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Reactive;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
 using System.Runtime.CompilerServices;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components;
 
 namespace ReactiveUI.Blazor
@@ -37,7 +35,7 @@ public class ReactiveComponentBase<T> : ComponentBase, IViewFor<T>, INotifyPrope
         /// </summary>
         public ReactiveComponentBase()
         {
-            this.WhenAnyValue(x => x.ViewModel).Subscribe(_ => StateHasChanged());
+            this.WhenAnyValue(x => x.ViewModel).Where(x => x != null).Subscribe(_ => StateHasChanged());
             var viewModelsPropertyChanged = this.WhenAnyValue(x => x.ViewModel)
                 .Where(x => x != null)
                 .Select(x => Observable.FromEvent<PropertyChangedEventHandler, Unit>(
diff --git a/src/ReactiveUI.Blazor/ReactiveLayoutComponentBase.cs b/src/ReactiveUI.Blazor/ReactiveLayoutComponentBase.cs
index b73b443993..e7ada4551e 100644
--- a/src/ReactiveUI.Blazor/ReactiveLayoutComponentBase.cs
+++ b/src/ReactiveUI.Blazor/ReactiveLayoutComponentBase.cs
@@ -33,7 +33,7 @@ public class ReactiveLayoutComponentBase<T> : LayoutComponentBase, IViewFor<T>,
         /// </summary>
         public ReactiveLayoutComponentBase()
         {
-            this.WhenAnyValue(x => x.ViewModel).Subscribe(_ => StateHasChanged());
+            this.WhenAnyValue(x => x.ViewModel).Where(x => x != null).Subscribe(_ => StateHasChanged());
             var viewModelsPropertyChanged = this.WhenAnyValue(x => x.ViewModel)
                 .Where(x => x != null)
                 .Select(x => Observable.FromEvent<PropertyChangedEventHandler, Unit>(
diff --git a/src/ReactiveUI.Blazor/ReactiveUI.Blazor.csproj b/src/ReactiveUI.Blazor/ReactiveUI.Blazor.csproj
index 2461bd56db..0687178296 100644
--- a/src/ReactiveUI.Blazor/ReactiveUI.Blazor.csproj
+++ b/src/ReactiveUI.Blazor/ReactiveUI.Blazor.csproj
@@ -7,7 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="Reactive.Wasm" Version="1.*" />
-    <PackageReference Include="Microsoft.AspNetCore.Components" Version="3.1.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Components" Version="3.1.1" />
   </ItemGroup>
 
   <ItemGroup>