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Developer that lives by the mantra "code is meant to be shared".




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Ensure.That v2 - yet another simple guard clause project

Daniel WertheimDaniel Wertheim

Recently I releasedEnsure.That v2.0.0, which is a simple guard clause project that simplifies and unifies your validation of arguments, for .Net4+, Silverlight, Windows Phone, WinRT.

It’s easy to get started. It’s distributed using NuGet and exists either as a dll or as a source package.

install-package ensure.that  

or for the source distribution:

install-package ensure.that.source  

What does it bring?

Simplified and unified argument validation.

public void Something(string myString) {  

If you want the name of the argument as the value for ArgumentException.ParamName, you pass it:

public void Something(string myString) {  
    Ensure.That(myString, "myString").IsNotNullOrEmpty();
    Ensure.That(myString, nameof(mystring)).IsNotNullOrEmpty();

You can chain:

public void Something(string myString) {  

    //same as

    //But could be simplified
    Ensure.That(myInt).IsInRange(1, 10);

    //You can assign the value to e.g. a property
    MyProperty = Ensure.That(myInt).Is(2).Value;

Wait, a magic string for the parameter name?

Yes, indeed. First. There’s an alternative so that you don’t need a magic string. Second. If you are, like me, a happer Visual Studio user cause of the daily use of ReSharper, I can tell you, it picks up those strings when you do e.g. name refactorings.

To get rid of the need of passing a string and instead use lambdas, you need to add an extenstion method as described here: https://github.com/danielwertheim/ensure.that/wiki/support-for-lambda-expressions

After that you can do:

public void Something(string myString) {  
    Ensure.That(() => myString).IsNotNullOrEmpty();

The reason to why this is not included, is that: the lambda expression-tree has negative effects on performance, as it needs to compile the expression to extract the value. May not sound like a big deal, but I want you to be aware of it, hence why you need to include it manually.


There are probably a bunch of stuff you can add that is missing. Please do. Follow this guide, and I’ll accept your pull request.

Ps! A logo would be nice as well.



Developer that lives by the mantra "code is meant to be shared".