ArgumentException Class

The exception that is thrown when one of the arguments provided to a method is not valid.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public class ArgumentException : SystemException, 

ArgumentException is thrown when a method is invoked and at least one of the passed arguments does not meet the parameter specification of the called method. All instances of ArgumentException should carry a meaningful error message describing the invalid argument, as well as the expected range of values for the argument.

The primary derived classes of ArgumentException are ArgumentNullException and ArgumentOutOfRangeException. These derived classes should be used instead of ArgumentException, except in situations where neither of the derived classes is acceptable. For example, exceptions should be thrown by:

  • ArgumentNullException whenever null is passed to a method that does not accept it as a valid argument.

  • ArgumentOutOfRangeException when the value of an argument is outside the range of acceptable values; for example, when the value "46" is passed as the month argument during the creation of a DateTime.

If the method call does not have any argument or if the failure does not involve the arguments themselves, then InvalidOperationException should be used.

ArgumentException uses the HRESULT COR_E_ARGUMENT, which has the value 0x80070057.

For a list of initial property values for an instance of ArgumentException, see the ArgumentException constructors.

The following example demonstrates how to throw and catch an ArgumentException.

using System;

public sealed class App 
    static void Main() 
        // ArgumentException is not thrown because 10 is an even number.
        Console.WriteLine("10 divided by 2 is {0}", DivideByTwo(10));
             // ArgumentException is thrown because 7 is not an even number.
             Console.WriteLine("7 divided by 2 is {0}", DivideByTwo(7));
        catch (ArgumentException)
            // Show the user that 7 cannot be divided by 2.
            Console.WriteLine("7 is not divided by 2 integrally.");

    static int DivideByTwo(int num) 
        // If num is an odd number, throw an ArgumentException. 
        if ((num & 1) == 1)
            throw new ArgumentException("Number must be even", "num");

        // num is even, return half of its value. 
        return num / 2;

// This code produces the following output. 
// 10 divided by 2 is 5 
// 7 is not divided by 2 integrally.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0