Added optional context parameter for Ouput operations. Fixes #1143

src/WorkflowCore/Interface/IStepBuilder.cs

@@ -89,13 +89,15 @@ public interface IStepBuilder<TData, TStepBody> : IWorkflowModifier<TData, TStep
         /// <param name="value"></param>
         /// <returns></returns>
         IStepBuilder<TData, TStepBody> Output<TOutput>(Expression<Func<TData, TOutput>> dataProperty, Expression<Func<TStepBody, object>> value);
+        IStepBuilder<TData, TStepBody> Output<TOutput>(Expression<Func<TData, IStepExecutionContext, TOutput>> dataProperty, Expression<Func<TStepBody, object>> value);
 
         /// <summary>
         /// Manipulate properties on the data object after the step executes
         /// </summary>
         /// <param name="action"></param>
         /// <returns></returns>
         IStepBuilder<TData, TStepBody> Output(Action<TStepBody, TData> action);
+        IStepBuilder<TData, TStepBody> Output(Action<TStepBody, TData, IStepExecutionContext> action);
 
         IStepBuilder<TData, TStep> End<TStep>(string name) where TStep : IStepBody;
 

src/WorkflowCore/Models/MemberMapParameter.cs

@@ -43,8 +43,9 @@ private void Assign(object sourceObject, LambdaExpression sourceExpr, object tar
             }
 
             var valueExpr = Expression.Convert(Expression.Constant(resolvedValue), targetExpr.ReturnType);
-            var assign = Expression.Lambda(Expression.Assign(targetExpr.Body, valueExpr), targetExpr.Parameters.Single());
-            assign.Compile().DynamicInvoke(targetObject);
+            var assign = Expression.Lambda(Expression.Assign(targetExpr.Body, valueExpr), targetExpr.Parameters);
+			if( targetExpr.Parameters.Count == 1 ) assign.Compile( ).DynamicInvoke( targetObject );
+			else assign.Compile( ).DynamicInvoke( targetObject, context );
         }
 
         public void AssignInput(object data, IStepBody body, IStepExecutionContext context)

src/WorkflowCore/Services/FluentBuilders/StepBuilder.cs

@@ -163,12 +163,24 @@ public IStepBuilder<TData, TStepBody> Output<TOutput>(Expression<Func<TData, TOu
             return this;
         }
 
+        public IStepBuilder<TData, TStepBody> Output<TOutput>(Expression<Func<TData, IStepExecutionContext, TOutput>> dataProperty, Expression<Func<TStepBody, object>> value)
+        {
+            Step.Outputs.Add(new MemberMapParameter(value, dataProperty));
+            return this;
+        }
+
         public IStepBuilder<TData, TStepBody> Output(Action<TStepBody, TData> action)
         {
             Step.Outputs.Add(new ActionParameter<TStepBody, TData>(action));
             return this;
         }
 
+        public IStepBuilder<TData, TStepBody> Output(Action<TStepBody, TData, IStepExecutionContext> action)
+        {
+            Step.Outputs.Add(new ActionParameter<TStepBody, TData>(action));
+            return this;
+        }
+
         public IStepBuilder<TData, WaitFor> WaitFor(string eventName, Expression<Func<TData, string>> eventKey, Expression<Func<TData, DateTime>> effectiveDate = null, Expression<Func<TData, bool>> cancelCondition = null)
         {
             var newStep = new WorkflowStep<WaitFor>();

test/WorkflowCore.UnitTests/Models/MemberMapParameterTests.cs

@@ -44,6 +44,23 @@ public void should_assign_output()
 
             data.Value1.Should().Be(step.Value1);
         }
+        [Fact]
+        public void should_assign_output_with_context()
+        {
+            Expression<Func<MyData, object>> memberExpr = (x => x.Value2);
+            Expression<Func<MyStep, StepExecutionContext, object>> valueExpr = ((step, context) => ((string[])step.Value2)[(int)context.Item]);
+            var subject = new MemberMapParameter(valueExpr, memberExpr);
+            var data = new MyData();
+            var step = new MyStep {
+                Value2 = new []{"A", "B", "C", "D"}
+            };
+
+            var context = new StepExecutionContext {Item = 2};
+
+            subject.AssignOutput(data, step, context);
+
+            data.Value2.Should().Be("C");
+        }
 
         [Fact]
         public void should_convert_input()