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POC# IsNullOrZero
 

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    <p>This pattern comes up very frequently in my code:</p> <pre><code>x= x== 0? 1: x; //or x= x==null? 1: x; </code></pre> <p>However it happens that sometimes x is a long expression and I'd have to use intermediate variables. That's just useless boilerplate code. I can cook up a method and call it instead: </p> <pre><code>Util.IfNullOrZero(x, 1); </code></pre> <p>But that's just ugly. What is the best way of expressing the pattern? In ruby there is such syntax for <strong>when x is nil</strong> which gets rid of redundant x's:</p> <pre><code>x||= 1 </code></pre> <p>I could extend <code>object</code> in a manner </p> <pre><code>public static class wtf { public static T Default&lt;T&gt;(this object o, T d) { return o == null ? d : new object[] { o }.Cast&lt;T&gt;().First(); } } </code></pre> <p>And then do </p> <pre><code>object param= null; int x= param.Default(1); </code></pre> <p>But that's a bit expensive. </p> <p>In short how to best make C# do x||= 1 like in ruby?</p> <p><strong>Update</strong></p> <p>This is what I cooked up. I'm currently looking for a faster way of using the Template parameter to convert object to T.</p> <pre><code>public static class MyExtensions { public static T d&lt;T&gt;(this object o, T d) { return o == null || o.Equals(default(T)) ? d : new object[] { o }.Cast&lt;T&gt;().First(); } } </code></pre> <p>In fact the code does three things at once: Casts to default type, checks for default value and also checks for null. </p> <p><strong>Update 2</strong></p> <pre><code>return o == null || o.Equals(default(T)) ? d : (T)o; // much simpler and faster </code></pre> <p>I still think it is a commonality which needs to be included in core language.</p> <p><strong>Update 3</strong> This is what I finally wrote, taking into account DataTable DBNull types.</p> <pre><code>public static T d&lt;T&gt;(this object o, T d) { return o == null || (o is System.DBNull) || o.Equals(default(T)) ? d : (T)Convert.ChangeType(o, typeof(T)); } </code></pre>
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    1. COpossible duplicate of [Is there anything like Or-Equals from Ruby in .NET/C#?](http://stackoverflow.com/questions/1478082/is-there-anything-like-or-equals-from-ruby-in-net-c)
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    2. COIt's not exactly what you're looking for, but the [null-coalescing operator](http://msdn.microsoft.com/en-us/library/ms173224.aspx) (`x ?? value`) is the same thing as `x == null ? value : x`
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    3. COYou can't force a dog to become a cat - such operator simply does not exist - the answers in the dupe question are the best you can hope for. :)
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