CA1420: Property, type, or attribute requires runtime marshalling

#Cause

A code feature is used that requires runtime marshalling, and runtime marshalling is explicitly disabled.

#Rule description

Using features that require runtime marshalling when runtime marshalling is disabled will result in runtime exceptions.

#How to fix violations

Enable runtime marshalling or remove the code that requires runtime marshalling.

#When to suppress warnings

Don't suppress a warning from this rule.

#Example

The following code snippet shows a violation of CA1420:

sample · csharpdocs/fundamentals/code-analysis/quality-rules/snippets/csharp/all-rules/ca1420.cs

using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

[assembly: DisableRuntimeMarshalling]

class C
{
    // Violates rule CA1420.
    [DllImport("NativeLibrary", SetLastError = true)]
    public static extern void MyMethod();
}

sample · vbdocs/fundamentals/code-analysis/quality-rules/snippets/vb/all-rules/ca1420.vb

Imports System.Runtime.InteropServices
Imports System.Runtime.CompilerServices

<Assembly: DisableRuntimeMarshalling>

Class C
    ' Violates rule CA1420.
    <DllImport("NativeLibrary", SetLastError:=True)>
    Public Shared Sub MyMethod()
        '...
    End Sub
End Class

To fix the violation, remove the System.Runtime.CompilerServices.DisableRuntimeMarshallingAttribute on the assembly.