BLAZMVVM0016: Messenger Registration Lifetime Analyzer

Diagnostic Information

Diagnostic ID: BLAZMVVM0016
Category: Blazing.Mvvm
Severity: Warning
Title: Messenger registration without unregistration

Description

Detects messenger registrations (Register calls) without corresponding unregistration (Unregister calls). In current Blazing.Mvvm versions, inheriting from ViewModelBase is not sufficient cleanup by itself; the ViewModel should unregister messages in Dispose(bool disposing) or use RecipientViewModelBase.

Examples

❌ Incorrect

public class MyViewModel : ViewModelBase
{
    public MyViewModel()
    {
        Messenger.Register<MyMessage>(this, HandleMessage); // ⚠️ Warning
    }
}

✅ Correct (With Dispose)

public class MyViewModel : ViewModelBase
{
    public MyViewModel()
    {
        Messenger.Register<MyMessage>(this, HandleMessage);
    }

    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            Messenger.UnregisterAll(this);
        }

        base.Dispose(disposing);
    }
}

✅ Correct (Using RecipientViewModelBase)

public class MyViewModel : RecipientViewModelBase
{
    protected override void OnActivated()
    {
        Messenger.Register<MyMessage>(this, HandleMessage);
        // Automatically unregistered on deactivation
    }
}

BLAZMVVM0015: Dispose Pattern Analyzer

Table of Contents