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Contract.Requires<TException> Method (Boolean, String)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Specifies a precondition contract for the enclosing method or property, and throws an exception with the provided message if the condition for the contract fails.

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

Syntax

'Declaration
Public Shared Sub Requires(Of TException As Exception) ( _
    condition As Boolean, _
    userMessage As String _
)

public static void Requires<TException>(
    bool condition,
    string userMessage
)
where TException : Exception

Type Parameters

  • TException
    The exception to throw if the condition is false.

Parameters

  • userMessage
    Type: System.String
    The message to display if the condition is false.

Remarks

  • This method call must be at the beginning of a method or property, before any other code.

  • This contract is exposed to clients; therefore, it must only reference members that are at least as visible as the enclosing method.

  • Use this method instead of the Contract.Requires(Boolean, String) method when you want to throw an exception if the precondition fails.

Version Information

Silverlight

Supported in: 5, 4

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.