Session01_Observer using delegate

DesignPattern.Observer.WithDelegate/DesignPattern.Observer.WithDelegate.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

DesignPattern.Observer.WithDelegate/IObserver.cs

@@ -0,0 +1,10 @@
+namespace DesignPattern.Observer;
+
+public interface IObserver
+{
+    public int Score { get; set; }
+    public void Update(int score)
+    {
+        Score = score;
+    }
+}

DesignPattern.Observer.WithDelegate/ISubject.cs

@@ -0,0 +1,8 @@
+namespace DesignPattern.Observer;
+
+public interface ISubject
+{
+    void Add(IObserver observer);
+    void Remove(IObserver observer);
+    void Notify(int score);
+}

DesignPattern.Observer.WithDelegate/Parent.cs

@@ -0,0 +1,11 @@
+namespace DesignPattern.Observer;
+
+public class Parent : IObserver
+{
+    public int Score { get; set; } = 15;
+
+    public override string ToString()
+    {
+        return "Parent Score: " + Score;
+    }
+}

DesignPattern.Observer.WithDelegate/Program.cs

@@ -0,0 +1,22 @@
+using DesignPattern.Observer;
+
+Subject subject = new Subject();
+var student = new Student();
+var parent = new Parent();
+var support = new Support();
+
+subject.Add(student);
+subject.Add(parent);
+subject.Add(support);
+
+subject.Score = 17;
+
+subject.Remove(parent);
+
+subject.Score = 7;
+
+Console.WriteLine(student.ToString());
+Console.WriteLine(parent.ToString());
+Console.WriteLine(support.ToString());
+
+Console.ReadKey();

DesignPattern.Observer.WithDelegate/Student.cs

@@ -0,0 +1,11 @@
+namespace DesignPattern.Observer;
+
+public class Student : IObserver
+{
+    public int Score { get; set; } = 0;
+
+    public override string ToString()
+    {
+        return "Student Score: " + Score;
+    }
+}

DesignPattern.Observer.WithDelegate/Subject.cs

@@ -0,0 +1,38 @@
+namespace DesignPattern.Observer;
+
+public class Subject : ISubject
+{
+    public delegate void Updater(int score);
+
+    private Updater? updaters;
+
+    public int Score
+    {
+        set
+        {
+            Notify(value);
+        }
+    }
+    public Subject() { }
+
+    public void Add(IObserver observer)
+    {
+        updaters += observer.Update;
+    }
+
+    public void Remove(IObserver observer)
+    {
+        updaters -= observer.Update;
+    }
+
+    public void Notify(int score)
+    {
+        //foreach (var observer in observers)
+        //{
+        //    observer.Update(20);
+        //}
+
+        if (updaters is not null)
+            updaters(score);
+    }
+}

DesignPattern.Observer.WithDelegate/Support.cs

@@ -0,0 +1,11 @@
+namespace DesignPattern.Observer;
+
+public class Support : IObserver
+{
+    public int Score { get; set; } = 8;
+
+    public override string ToString()
+    {
+        return "Support Score: " + Score;
+    }
+}

DesignPatternsSln.sln

@@ -13,9 +13,11 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Behavioral", "Behavioral",
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Observers", "Observers", "{3EBD3060-2125-4B77-B802-9D3BB30C4A69}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DesignPattern.Observer", "DesignPattern.Observer\DesignPattern.Observer.csproj", "{2A5FDACE-5DDE-4216-92F0-6752D1164862}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DesignPattern.Observer", "DesignPattern.Observer\DesignPattern.Observer.csproj", "{2A5FDACE-5DDE-4216-92F0-6752D1164862}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DesignPattern.Observer.WithMarker", "DesignPattern.Observer.WithMarker\DesignPattern.Observer.WithMarker.csproj", "{BACC3D89-38DC-443F-BE56-1F1C6C63408F}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DesignPattern.Observer.WithMarker", "DesignPattern.Observer.WithMarker\DesignPattern.Observer.WithMarker.csproj", "{BACC3D89-38DC-443F-BE56-1F1C6C63408F}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DesignPattern.Observer.WithDelegate", "DesignPattern.Observer.WithDelegate\DesignPattern.Observer.WithDelegate.csproj", "{9D21F7B3-2876-429E-98E7-0B1C19C6C0EC}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -31,6 +33,10 @@ Global
 		{BACC3D89-38DC-443F-BE56-1F1C6C63408F}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{BACC3D89-38DC-443F-BE56-1F1C6C63408F}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{BACC3D89-38DC-443F-BE56-1F1C6C63408F}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9D21F7B3-2876-429E-98E7-0B1C19C6C0EC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9D21F7B3-2876-429E-98E7-0B1C19C6C0EC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9D21F7B3-2876-429E-98E7-0B1C19C6C0EC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9D21F7B3-2876-429E-98E7-0B1C19C6C0EC}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -42,6 +48,7 @@ Global
 		{3EBD3060-2125-4B77-B802-9D3BB30C4A69} = {C40F78D1-E305-45D6-AA98-D4BF7BA60DDB}
 		{2A5FDACE-5DDE-4216-92F0-6752D1164862} = {3EBD3060-2125-4B77-B802-9D3BB30C4A69}
 		{BACC3D89-38DC-443F-BE56-1F1C6C63408F} = {3EBD3060-2125-4B77-B802-9D3BB30C4A69}
+		{9D21F7B3-2876-429E-98E7-0B1C19C6C0EC} = {3EBD3060-2125-4B77-B802-9D3BB30C4A69}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {BA635945-9BC8-4FB5-AB66-9B1DC002F830}