dotnet/Documentation/compatibility/workflow-now-throws-original-exception-instead-of-nullreferenceexception-in-some-cases.md

Workflow now throws original exception instead of NullReferenceException in some cases

Scope

Minor

Version Introduced

4.7

Source Analyzer Status

NotPlanned

Change Description

In the .NET Framework 4.6.2 and earlier versions, when the Execute method of a workflow activity throws an exception with a null value for the P:System.Exception.Message property, the System.Activities Workflow runtime throws a NullReferenceException, masking the original exception.

In the .NET Framework 4.7, the previously masked exception is thrown.

• Quirked
• Build-time break

Recommended Action

If your code relies on handling the NullReferenceException, change it to catch the exceptions that could be thrown from your custom activities.

Affected APIs

• M:System.Activities.CodeActivity.Execute(System.Activities.CodeActivityContext)
• M:System.Activities.AsyncCodeActivity.BeginExecute(System.Activities.AsyncCodeActivityContext,System.AsyncCallback,System.Object)
• M:System.Activities.AsyncCodeActivity1.BeginExecute(System.Activities.AsyncCodeActivityContext,System.AsyncCallback,System.Object)`
• M:System.Activities.WorkflowInvoker.Invoke

Category

Windows Workflow Foundation (WF)