From 710f9fa03b5cea3d60906edb977133e37a19ebf6 Mon Sep 17 00:00:00 2001
From: Laoujin <woutervs@hotmail.com>
Date: Sat, 31 Jan 2015 23:14:58 +0100
Subject: [CSharp/en]Added exception handling
---
csharp.html.markdown | 36 ++++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)
diff --git a/csharp.html.markdown b/csharp.html.markdown
index 4258a0c6..df265d8c 100644
--- a/csharp.html.markdown
+++ b/csharp.html.markdown
@@ -462,6 +462,31 @@ on a new line! ""Wow!"", the masses cried";
Func<int, int> square = (x) => x * x; // Last T item is the return value
Console.WriteLine(square(3)); // 9
+ // ERROR HANDLING - coping with an uncertain world
+ try
+ {
+ var funBike = PennyFarthing.CreateWithGears(6);
+
+ // will no longer execute because CreateWithGears throws an exception
+ string some = "";
+ if (true) some = null;
+ some.ToLower(); // throws a NullReferenceException
+ }
+ catch (NotSupportedException)
+ {
+ Console.WriteLine("Not so much fun now!");
+ }
+ catch (Exception ex) // catch all other exceptions
+ {
+ throw new ApplicationException("It hit the fan", ex);
+ // throw; // A rethrow that preserves the callstack
+ }
+ // catch { } // catch-all without capturing the Exception
+ finally
+ {
+ // executes after try or catch
+ }
+
// DISPOSABLE RESOURCES MANAGEMENT - let you handle unmanaged resources easily.
// Most of objects that access unmanaged resources (file handle, device contexts, etc.)
// implement the IDisposable interface. The using statement takes care of
@@ -780,10 +805,17 @@ on a new line! ""Wow!"", the masses cried";
}
set
{
- throw new ArgumentException("You can't change gears on a PennyFarthing");
+ throw new InvalidOperationException("You can't change gears on a PennyFarthing");
}
}
+ public static PennyFarthing CreateWithGears(int gears)
+ {
+ var penny = new PennyFarthing(1, 1);
+ penny.Gear = gears; // Oops, can't do this!
+ return penny;
+ }
+
public override string Info()
{
string result = "PennyFarthing bicycle ";
@@ -842,7 +874,7 @@ on a new line! ""Wow!"", the masses cried";
## Topics Not Covered
* Attributes
- * Exceptions, Abstraction
+ * Abstraction
* ASP.NET (Web Forms/MVC/WebMatrix)
* Winforms
* Windows Presentation Foundation (WPF)
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