CA2250: Use ThrowIfCancellationRequested

Cause

This rule flags conditional statements that check IsCancellationRequested before throwing OperationCanceledException.

Rule description

You can accomplish the same thing by calling CancellationToken.ThrowIfCancellationRequested().

How to fix violations

To fix violations, replace the conditional statement with a call to ThrowIfCancellationRequested().

using System;
using System.Threading;

public void MySlowMethod(CancellationToken token)
{
    // Violation
    if (token.IsCancellationRequested)
        throw new OperationCanceledException();

    // Fix
    token.ThrowIfCancellationRequested();

    // Violation
    if (token.IsCancellationRequested)
        throw new OperationCanceledException();
    else
        DoSomethingElse();

    // Fix
    token.ThrowIfCancellationRequested();
    DoSomethingElse();
}

Imports System
Imports System.Threading

Public Sub MySlowMethod(token As CancellationToken)

    ' Violation
    If token.IsCancellationRequested Then
        Throw New OperationCanceledException()
    End If

    ' Fix
    token.ThrowIfCancellationRequested()

    ' Violation
    If token.IsCancellationRequested Then
        Throw New OperationCanceledException()
    Else
        DoSomethingElse()
    End If

    ' Fix
    token.ThrowIfCancellationRequested()
    DoSomethingElse()
End Sub

When to suppress warnings

It is safe to suppress warnings from this rule.

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable CA2250
// The code that's violating the rule is on this line.
#pragma warning restore CA2250

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.CA2250.severity = none

For more information, see How to suppress code analysis warnings.

See also

• Usage Warnings