System.ArgumentNullException Class

Namespace: System

Assembly: System.Runtime.dll

Represents an error that occurs when a null reference is passed to a method that does not accept it as a valid argument.

Syntax

public class ArgumentNullException : ArgumentException

Constructors

Signature	Description
`ArgumentNullException()`	Initializes a new instance with a default error message.
`ArgumentNullException(string paramName)`	Initializes with the name of the parameter that caused the exception.
`ArgumentNullException(string paramName, string message)`	Initializes with a custom message and parameter name.
`ArgumentNullException(string paramName, Exception innerException)`	Initializes with a parameter name and a reference to the inner exception that is the cause of this exception.
`ArgumentNullException(string message, Exception innerException)`	Initializes with a custom message and inner exception.

Properties

Property	Type	Description
`ParamName`	string	Gets the name of the parameter that caused the exception.
`Message`	string	Gets a message that describes the current exception.
`InnerException`	Exception	The underlying exception, if any.

Remarks

Use ArgumentNullException to indicate that a method argument was null when it shouldn't be. Providing the parameter name through the constructor helps consumers of the API quickly identify the problematic argument.

Example

public void SetName(string name)
{
    if (name == null)
        throw new ArgumentNullException(nameof(name));

    // Continue processing...
}

This example checks that name is not null and throws ArgumentNullException with the appropriate parameter name.

.NET API Reference