CM-244 Difference between "throw" and "throw ex" in C#

csharp-advanced-topics/ExceptionHandling/ExceptionHandling.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31903.59
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ThrowVsThrowEx", "ThrowVsThrowEx\ThrowVsThrowEx.csproj", "{7E86B846-BE84-4BAA-BC9A-56872F6D9EF9}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{7E86B846-BE84-4BAA-BC9A-56872F6D9EF9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7E86B846-BE84-4BAA-BC9A-56872F6D9EF9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7E86B846-BE84-4BAA-BC9A-56872F6D9EF9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7E86B846-BE84-4BAA-BC9A-56872F6D9EF9}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {BCFF6A56-AED0-439E-A464-8FB6242B29C3}
+	EndGlobalSection
+EndGlobal

csharp-advanced-topics/ExceptionHandling/ThrowVsThrowEx/ThrowVsThrowEx.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
+	  <DebugType>None</DebugType>
+	  <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="NUnit" Version="3.13.2" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="coverlet.collector" Version="3.1.0" />
+  </ItemGroup>
+
+</Project>

csharp-advanced-topics/ExceptionHandling/ThrowVsThrowEx/ThrowVsThrowExSamples.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Metrics;
+using System.Linq;
+using System.Threading.Channels;
+using NUnit.Framework;
+
+namespace ThrowVsThrowEx
+{
+    public class ThrowVsThrowExSamples
+    {
+        [Test]
+        public void ThrowBehaviour_KeepsProperStackTrace()
+        {
+            try
+            {
+                new BusinessWorker().Work_Throw();
+            }
+            catch (Exception ex)
+            {
+                Assert.AreEqual(
+                    @"System.InvalidOperationException: That's a nasty bug!
+   at ThrowVsThrowEx.ThirdPartyComponent.<GoDeeper>g__DoDangerousOperation|1_0()
+   at ThrowVsThrowEx.ThirdPartyComponent.GoDeeper()
+   at ThrowVsThrowEx.ThirdPartyComponent.DoInternalWork()
+   at ThrowVsThrowEx.BusinessWorker.Work_Throw()
+   at ThrowVsThrowEx.ThrowVsThrowExSamples.ThrowBehaviour_KeepsProperStackTrace()",
+                    ex.ToString());
+
+            }
+        }
+
+        [Test]
+        public void ThrowEx_DropsTheStackTrace()
+        {
+            try
+            {
+                new BusinessWorker().Work_ThrowEx();
+            }
+            catch (Exception ex)
+            {
+                Assert.AreEqual(
+                    @"System.InvalidOperationException: That's a nasty bug!
+   at ThrowVsThrowEx.BusinessWorker.Work_ThrowEx()
+   at ThrowVsThrowEx.ThrowVsThrowExSamples.ThrowEx_DropsTheStackTrace()",
+                    ex.ToString());
+            }
+        }
+
+        [Test]
+        public void WrapAndThrowNewEx_KeepsTheStackTraceInTheInnerException()
+        {
+            try
+            {
+                new BusinessWorker().Work_WrapAndThrowNewEx();
+            }
+            catch (Exception ex)
+            {
+                //the stack trace of the top level exception is short
+                Assert.AreEqual(@"   at ThrowVsThrowEx.BusinessWorker.Work_WrapAndThrowNewEx()
+   at ThrowVsThrowEx.ThrowVsThrowExSamples.WrapAndThrowNewEx_KeepsTheStackTraceInTheInnerException()", ex.StackTrace);
+                //however, the actual exception and it's stack trace is visible within the ex.InnerException property
+                //the full exception string also reveals all the layers of inner exceptions
+                Assert.AreEqual(
+                    @"ThrowVsThrowEx.BusinessWorker+BusinessException: I am a business domain wrapper for internal exceptions.
+ ---> System.InvalidOperationException: That's a nasty bug!
+   at ThrowVsThrowEx.ThirdPartyComponent.<GoDeeper>g__DoDangerousOperation|1_0()
+   at ThrowVsThrowEx.ThirdPartyComponent.GoDeeper()
+   at ThrowVsThrowEx.ThirdPartyComponent.DoInternalWork()
+   at ThrowVsThrowEx.BusinessWorker.Work_WrapAndThrowNewEx()
+   --- End of inner exception stack trace ---
+   at ThrowVsThrowEx.BusinessWorker.Work_WrapAndThrowNewEx()
+   at ThrowVsThrowEx.ThrowVsThrowExSamples.WrapAndThrowNewEx_KeepsTheStackTraceInTheInnerException()",
+                    ex.ToString());
+            }
+        }
+    }
+}

csharp-advanced-topics/ExceptionHandling/ThrowVsThrowEx/WorkerClasses.cs

@@ -0,0 +1,75 @@
+using System;
+
+namespace ThrowVsThrowEx
+{
+    public class BusinessWorker
+    {
+        public void Work_Throw()
+        {
+            try
+            {
+                //lots of other business logic all around...
+                new ThirdPartyComponent().DoInternalWork();
+            }
+            catch (Exception ex)
+            {
+                //here we would handle 'ex' in the BusinessWorker (clean up resources, log state, call 911 etc.)
+                throw;
+            }
+        }
+
+        public void Work_ThrowEx()
+        {
+            try
+            {
+                //lots of other business logic all around...
+                new ThirdPartyComponent().DoInternalWork();
+            }
+            catch (Exception ex)
+            {
+                //here we would handle 'ex' in the BusinessWorker (clean up resources, log state, call 911 etc.)
+                throw ex;
+            }
+        }
+
+        public void Work_WrapAndThrowNewEx()
+        {
+            try
+            {
+                //lots of other business logic all around...
+                new ThirdPartyComponent().DoInternalWork();
+            }
+            catch (Exception ex)
+            {
+                //here we would handle 'ex' in the BusinessWorker (clean up resources, log state, call 911 etc.)
+                throw new BusinessException("I am a business domain wrapper for internal exceptions.", ex);
+            }
+        }
+
+        class BusinessException : Exception
+        {
+            public BusinessException(string? message, Exception? innerException) : base(message, innerException)
+            {
+            }
+        }
+
+
+    }
+
+    public class ThirdPartyComponent
+    {
+        public void DoInternalWork()
+        {
+            GoDeeper();
+        }
+
+        private void GoDeeper()
+        {
+            DoDangerousOperation();
+            void DoDangerousOperation()
+            {
+                throw new InvalidOperationException("That's a nasty bug!");
+            }
+        }
+    }
+}