Enable nullable annotations for Volo.Abp.BackgroundWorkers

framework/src/Volo.Abp.BackgroundWorkers/Volo.Abp.BackgroundWorkers.csproj

@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.BackgroundWorkers</AssemblyName>
     <PackageId>Volo.Abp.BackgroundWorkers</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>

framework/src/Volo.Abp.BackgroundWorkers/Volo/Abp/BackgroundWorkers/BackgroundWorkerBase.cs

@@ -14,13 +14,13 @@ public abstract class BackgroundWorkerBase : IBackgroundWorker
 {
     //TODO: Add UOW, Localization and other useful properties..?
 
-    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }
+    public IAbpLazyServiceProvider LazyServiceProvider { get; set; } = default!;
 
-    public IServiceProvider ServiceProvider { get; set; }
+    public IServiceProvider ServiceProvider { get; set; } = default!;
 
     protected ILoggerFactory LoggerFactory => LazyServiceProvider.LazyGetRequiredService<ILoggerFactory>();
 
-    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName) ?? NullLogger.Instance);
+    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName!) ?? NullLogger.Instance);
 
     protected CancellationTokenSource StoppingTokenSource { get; }
     protected CancellationToken StoppingToken { get; }
@@ -47,6 +47,6 @@ public abstract class BackgroundWorkerBase : IBackgroundWorker
 
     public override string ToString()
     {
-        return GetType().FullName;
+        return GetType().FullName!;
     }
 }

framework/src/Volo.Abp.BackgroundWorkers/Volo/Abp/BackgroundWorkers/PeriodicBackgroundWorkerBase.cs

@@ -37,7 +37,7 @@ public abstract class PeriodicBackgroundWorkerBase : BackgroundWorkerBase
         await base.StopAsync(cancellationToken);
     }
 
-    private void Timer_Elapsed(object sender, System.EventArgs e)
+    private void Timer_Elapsed(object? sender, System.EventArgs e)
     {
         using (var scope = ServiceScopeFactory.CreateScope())
         {