CA2257: Members defined on an interface with the 'DynamicInterfaceCastableImplementationAttribute' should be 'static'

Property	Value
Rule ID	CA2257
Title	Members defined on an interface with the 'DynamicInterfaceCastableImplementationAttribute' should be 'static'
Category	Usage
Fix is breaking or non-breaking	Non-breaking
Enabled by default in .NET 10	As warning
Applicable languages	C# and Visual Basic

Cause

An interface member isn't explicitly implemented or marked static.

Rule description

Since a type that implements IDynamicInterfaceCastable may not implement a dynamic interface in metadata, calls to an instance interface member that is not an explicit implementation defined on this type are likely to fail at runtime. To avoid runtime errors, mark new interface members static.

How to fix violations

Mark the interface member static.

Example

[DynamicInterfaceCastableImplementation]
interface IExample
{
    // This method violates the rule.
    void BadMethod();

    // This method satisfies the rule.
    static void GoodMethod()
    {
        // ...
    }
}

When to suppress errors

Do not suppress a warning from this rule.

See also

• Usage warnings
• CA2256: All members declared in parent interfaces must have an implementation in a DynamicInterfaceCastableImplementation-attributed interface