C# Programming/Keywords/typeof
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The typeof
keyword returns an instance of the System.Type
class when passed a name of a class. It is similar to the sizeof
keyword in that it returns a value instead of starting a section (block) of code (see if, try, while).
An example:
using System;
namespace MyNamespace
{
class MyClass
{
static void Main(string[] args)
{
Type t = typeof(int);
Console.Out.WriteLine(t.ToString());
Console.In.Read();
}
}
}
The output will be:
System.Int32
It should be noted that unlike sizeof
, only class names themselves and not variables can be passed to typeof
as shown here:
using System;
namespace MyNamespace { class MyClass2 { static void Main(string[] args) { char ch; // This line will cause compilation to fail Type t = typeof(ch); Console.Out.WriteLine(t.ToString()); Console.In.Read(); } } }
Sometimes, classes will include their own GetType()
method that will be similar, if not identical, to typeof
.
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