PX1077.md

PX1077

This document describes the PX1077 diagnostic.

Summary

Code	Short Description	Type	Code Fix
PX1077	Event handlers in graphs and graph extensions should have the protected and virtual modifiers.	Error	Available

Diagnostic Description

The accessibility level of an event handler should have the protected modifier, and the method should have the virtual or override modifier. Private event handlers can lead to unexpected behavior, and it is not guaranteed that such event handlers will be invoked by the Acumatica Framework. Making the event handler virtual is a good practice for API design; it allows the derived classes to override the method and change the implementation.

Further Notes

• If the event handler is already overridden, the diagnostic will not show an error.
• Explicit interface implementations are effectively private. The diagnostic will show only a warning for such implementations.
• If the container type is sealed, the code fix will propose the public modifier and no virtual modifier.
• The diagnostic will show an error for the private modifier and only a warning for other access modifiers.

Example of Correct Code

The following example demonstrates the correct implementation of an event handler.

public class MyGraph : PXGraph<MyGraph>
{
}

public class MyGraphExtension : PXGraphExtension<MyGraph>
{
	protected virtual void HandleDocTypeFieldUpdated(Events.FieldUpdated<PX.Objects.AR.ARInvoice.docType> e)
	{
	}
}

Example of Correct Code

In the following example, the access modifier is public because the method implements an interface.

public class MyGraph : PXGraph<MyGraph>
{
}

public interface IMyGraphExtension
{
	void HandleDocTypeFieldUpdated(Events.FieldUpdated<PX.Objects.AR.ARInvoice.docType> e);
}

public class MyGraphExtension : PXGraphExtension<MyGraph>, IMyGraphExtension
{
	public void HandleDocTypeFieldUpdated(Events.FieldUpdated<PX.Objects.AR.ARInvoice.docType> e)
	{
	}
}

Example of Correct Code

In the following example, the access modifier is public and not virtual because the container type is sealed.

public class MyGraph : PXGraph<MyGraph>
{
}

public sealed class MyGraphExtension : PXGraphExtension<MyGraph>
{
	public void HandleDocTypeFieldUpdated(Events.FieldUpdated<PX.Objects.AR.ARInvoice.docType> e)
	{
	}
}

Example of Correct Code

In the following example, the access modifier should be protected and virtual.

public class MyGraph : PXGraph<MyGraph>
{
}

public class MyGraphExtension : PXGraphExtension<MyGraph>
{
	private void HandleDocTypeFieldUpdated(Events.FieldUpdated<PX.Objects.AR.ARInvoice.docType> e)
	{
	}
}