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typeof

The typeof operator is used to obtain the System.Type object for a type. A typeof expression takes the form:

typeof(type)

where:

type
The type for which the System.Type object is obtained.

Remarks

The typeof operator cannot be overloaded.

To obtain the run-time type of an expression, you can use the .NET Framework method GetType.

Example

// cs_operator_typeof.cs
// Using typeof operator
using System;
using System.Reflection;

public class MyClass 
{
   public int intI;
   public void MyMeth() 
   {
   }

   public static void Main() 
   {
      Type t = typeof(MyClass);

      // alternatively, you could use
      // MyClass t1 = new MyClass();
      // Type t = t1.GetType();

      MethodInfo[] x = t.GetMethods();
      foreach (MethodInfo xtemp in x) 
      {
         Console.WriteLine(xtemp.ToString());
      }

      Console.WriteLine();

      MemberInfo[] x2 = t.GetMembers();
      foreach (MemberInfo xtemp2 in x2) 
      {
         Console.WriteLine(xtemp2.ToString());
      }
   }
}

Output

Int32 GetHashCode()
Boolean Equals(System.Object)
System.String ToString()
Void MyMeth()
Void Main()
System.Type GetType()

Int32 intI
Int32 GetHashCode()
Boolean Equals(System.Object)
System.String ToString()
Void MyMeth()
Void Main()
System.Type GetType()
Void .ctor()

Example

// cs_operator_typeof2.cs
// Using GetType method
using System;
class GetTypeTest 
{
   public static void Main() 
   {
      int radius = 3;
      Console.WriteLine("Area = {0}", radius*radius*Math.PI);
      Console.WriteLine("The type is {0}", 
               (radius*radius*Math.PI).GetType());
   }
}

Output

Area = 28.2743338823081
The type is System.Double

See Also

C# Keywords | is | Operator Keywords

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