a few more updates

Author: gewarren

snippets/csharp/System/EventArgs/Overview/Project.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net8.0</TargetFramework>
+    <nullable>enable</nullable>
   </PropertyGroup>
 
 </Project>

snippets/csharp/System/EventArgs/Overview/program.cs

@@ -1 +1,4 @@
 ConsoleApplication1.Program1.Main();
+ConsoleApplication2.Program2.Main();
+ConsoleApplication3.Program3.Main();
+ConsoleApplication4.Program4.Main();

snippets/csharp/System/EventArgs/Overview/programnodata.cs

@@ -18,7 +18,7 @@ public static void Main()
             }
         }
 
-        static void c_ThresholdReached(object sender, EventArgs e)
+        static void c_ThresholdReached(object? sender, EventArgs e)
         {
             Console.WriteLine("The threshold was reached.");
             Environment.Exit(0);
@@ -46,14 +46,10 @@ public void Add(int x)
 
         protected virtual void OnThresholdReached(EventArgs e)
         {
-            EventHandler handler = ThresholdReached;
-            if (handler != null)
-            {
-                handler(this, e);
-            }
+            ThresholdReached?.Invoke(this, e);
         }
 
-        public event EventHandler ThresholdReached;
+        public event EventHandler? ThresholdReached;
     }
 }
 // </snippet5>

snippets/csharp/System/EventArgs/Overview/programtruncated.cs

@@ -13,7 +13,7 @@ public static void Main()
             // provide remaining implementation for the class
         }
 
-        static void c_ThresholdReached(object sender, EventArgs e)
+        static void c_ThresholdReached(object? sender, EventArgs e)
         {
             Console.WriteLine("The threshold was reached.");
         }
@@ -23,11 +23,11 @@ static void c_ThresholdReached(object sender, EventArgs e)
     // <snippet1>
     class Counter
     {
-        public event EventHandler ThresholdReached;
+        public event EventHandler? ThresholdReached;
 
         protected virtual void OnThresholdReached(EventArgs e)
         {
-            EventHandler handler = ThresholdReached;
+            EventHandler? handler = ThresholdReached;
             handler?.Invoke(this, e);
         }
 

snippets/csharp/System/EventArgs/Overview/programwithdata.cs

@@ -5,7 +5,7 @@ namespace ConsoleApplication3
 {
     public class Program3
     {
-        public static void Main(string[] args)
+        public static void Main()
         {
             Counter c = new(new Random().Next(10));
             c.ThresholdReached += c_ThresholdReached;
@@ -40,23 +40,21 @@ public void Add(int x)
             _total += x;
             if (_total >= _threshold)
             {
-                ThresholdReachedEventArgs args = new ThresholdReachedEventArgs();
-                args.Threshold = _threshold;
-                args.TimeReached = DateTime.Now;
+                ThresholdReachedEventArgs args = new()
+                {
+                    Threshold = _threshold,
+                    TimeReached = DateTime.Now
+                };
                 OnThresholdReached(args);
             }
         }
 
         protected virtual void OnThresholdReached(ThresholdReachedEventArgs e)
         {
-            EventHandler<ThresholdReachedEventArgs> handler = ThresholdReached;
-            if (handler != null)
-            {
-                handler(this, e);
-            }
+            ThresholdReached?.Invoke(this, e);
         }
 
-        public event EventHandler<ThresholdReachedEventArgs> ThresholdReached;
+        public event EventHandler<ThresholdReachedEventArgs>? ThresholdReached;
     }
 
     public class ThresholdReachedEventArgs : EventArgs

snippets/csharp/System/EventArgs/Overview/programwithdelegate.cs

@@ -5,7 +5,7 @@ namespace ConsoleApplication4
 {
     class Program4
     {
-        public static void Main(string[] args)
+        public static void Main()
         {
             Counter c = new(new Random().Next(10));
             c.ThresholdReached += c_ThresholdReached;
@@ -18,7 +18,7 @@ public static void Main(string[] args)
             }
         }
 
-        public static void c_ThresholdReached(object sender, ThresholdReachedEventArgs e)
+        public static void c_ThresholdReached(object? sender, ThresholdReachedEventArgs e)
         {
             Console.WriteLine("The threshold of {0} was reached at {1}.", e.Threshold, e.TimeReached);
             Environment.Exit(0);
@@ -40,23 +40,21 @@ public void Add(int x)
             _total += x;
             if (_total >= _threshold)
             {
-                ThresholdReachedEventArgs args = new ThresholdReachedEventArgs();
-                args.Threshold = _threshold;
-                args.TimeReached = DateTime.Now;
+                ThresholdReachedEventArgs args = new()
+                {
+                    Threshold = _threshold,
+                    TimeReached = DateTime.Now
+                };
                 OnThresholdReached(args);
             }
         }
 
         protected virtual void OnThresholdReached(ThresholdReachedEventArgs e)
         {
-            ThresholdReachedEventHandler handler = ThresholdReached;
-            if (handler != null)
-            {
-                handler(this, e);
-            }
+            ThresholdReached?.Invoke(this, e);
         }
 
-        public event ThresholdReachedEventHandler ThresholdReached;
+        public event ThresholdReachedEventHandler? ThresholdReached;
     }
 
     public class ThresholdReachedEventArgs : EventArgs
@@ -65,6 +63,6 @@ public class ThresholdReachedEventArgs : EventArgs
         public DateTime TimeReached { get; set; }
     }
 
-    public delegate void ThresholdReachedEventHandler(Object sender, ThresholdReachedEventArgs e);
+    public delegate void ThresholdReachedEventHandler(object sender, ThresholdReachedEventArgs e);
 }
 // </snippet7>