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copied!<p>Seems everyone is doing it really complicated, with long lists of conditions or big <code>switch</code> statements.</p> <p>There are multiple possible interpretations of what you think of as primitive types.</p> <h3>1. .NET primitive types</h3> <p>.NET has a list of types that it considers to be primitive types. On the <a href="http://msdn.microsoft.com/en-us/library/42892f65.aspx" rel="nofollow"><code>Type</code> class</a> there is a property <a href="http://msdn.microsoft.com/en-us/library/system.type.isprimitive.aspx" rel="nofollow"><code>IsPrimitive</code> property</a> that will return <code>true</code> for any of these primitive types and <code>false</code> for any other type.</p> <blockquote> <p>The primitive types are Boolean, Byte, SByte, Int16, UInt16, Int32, UInt32, Int64, UInt64, IntPtr, UIntPtr, Char, Double, and Single.</p> </blockquote> <p>Note that <code>IntPtr</code> and <code>UIntPtr</code> are also in there. They represent the platform-specific integer type (e.g. 32-bit integer on a 32-bit computer, 64-bit on a 64-bit computer). Also note that .NET does not consider <code>String</code> or <code>Decimal</code> to be a primitive.</p> <p>You can test it like this:</p> <pre><code>public static bool IsPrimitiveType(Type type) { return type.IsPrimitive; } </code></pre> <h3>2. .NET primitive types and String and Decimal</h3> <p>In your question you have included the <code>String</code> and <code>Decimal</code> types in your definition of a primitive type. Let's test for those too, like this:</p> <pre><code>public static bool IsPrimitiveType(Type type) { return type.IsPrimitive || type == typeof(decimal) || type == typeof(string); } </code></pre> <p>Since it is impossible to extend <code>String</code> or <code>Decimal</code>, simple type equality will suffice here.</p> <h3>3. Built-in C# types</h3> <p>If your definition of primitive types is the list of <a href="http://msdn.microsoft.com/en-gb/library/ya5y69ds.aspx" rel="nofollow">Built-in Types Table (C# Reference)</a> on MSDN, we have to exclude <code>IntPtr</code> and <code>UIntPtr</code> because they are not in that list.</p> <pre><code>public static bool IsPrimitiveType(Type type) { return (type.IsPrimitive && type != typeof(UIntPtr) && type != typeof(IntPtr)) || type == typeof(decimal) || type == typeof(string); } </code></pre> <h3>4. Something else entirely</h3> <p>Based on the previous examples you can see how to exclude or include additional types in your definition of a <em>primitive type</em> if you want to.</p> <hr> <p>In all the above examples, you can call the <code>IsPrimitiveType</code> method like this:</p> <ol> <li><p>If you have an object instance <code>obj</code>:</p> <pre><code>bool isPrimitive = IsPrimitiveType(obj.GetType()); </code></pre></li> <li><p>If you have a type <code>someType</code>:</p> <pre><code>bool isPrimitive = IsPrimitiveType(someType); </code></pre></li> <li><p>If you have a generic type parameter <code>T</code>:</p> <pre><code>bool isPrimitive = IsPrimitiveType(typeof(T)); </code></pre></li> <li><p>If you have a type known at compile time, e.g. <code>Int32</code>:</p> <pre><code>bool isPrimitive = IsPrimitiveType(typeof(Int32)); </code></pre></li> </ol>

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