无法使用 WF 4.5 中的 CSharpValue 表达式访问字典

Question

我已尝试使用代码创建工作流，如 here 所述。但是我无法通过我的结果。我创建了控制台应用程序 Class1.cs 包含我的工作流代码和 Program.cs 工作流托管在 WorkflowApplication class 中，包括输入。在执行消息时发生未处理的异常 "Expression Activity type 'CSharpValue`1' requires compilation in order to run. Please ensure that the workflow has been compiled"。但我也有 包括用于编译的方法 CompileExpressions，如 here 所述。非常感谢您的帮助！

ReverseStringWorkflow.cs

 public class ReverseStringWorkflow : Activity
    {
        public InArgument<Dictionary<string,object>> StringToReverse { get; set; } 

        protected override Func<Activity> Implementation
        {
            get
            {
                return () =>
                {
                    Sequence sequence = new Sequence
                    {
                        Activities =
                        {
                             new WriteLine
                             {
                                 Text = new CSharpValue<string>("StringToReverse[\"name\"].ToString()")

                             }
                        }
                    };
                    return sequence;
                };
            }
            set
            {
                base.Implementation = value;
            }

        }
    }

Program.cs

class Program
    {
        static void Main(string[] args)
        {
            Activity workflow2 = new ReverseStringWorkflow();
            Dictionary<string, object> mainInputs = new Dictionary<string, object>();
            Dictionary<string, object> subInputs = new Dictionary<string, object>();                
            subInputs.Add("name","name123");
            mainInputs.Add("StringToReverse", subInputs);
            WorkflowApplication app = new WorkflowApplication(workflow2, mainInputs);
            app.OnUnhandledException = delegate (WorkflowApplicationUnhandledExceptionEventArgs e)
            {
                Console.WriteLine("Error occurred");
                return UnhandledExceptionAction.Terminate;
            };
            CompileExpressions(workflow2);

            app.Run();

            Console.ReadLine();
        }
        public static void CompileExpressions(Activity activity)
        {
            // activityName is the Namespace.Type of the activity that contains the
            // C# expressions.
            string activityName = activity.GetType().ToString();

            // Split activityName into Namespace and Type.Append _CompiledExpressionRoot to the type name
            // to represent the new type that represents the compiled expressions.
            // Take everything after the last . for the type name.
            string activityType = activityName.Split('.').Last() + "_CompiledExpressionRoot";
            // Take everything before the last . for the namespace.
            string activityNamespace = string.Join(".", activityName.Split('.').Reverse().Skip(1).Reverse());

            // Create a TextExpressionCompilerSettings.
            TextExpressionCompilerSettings settings = new TextExpressionCompilerSettings
            {
                Activity = activity,
                Language = "C#",
                ActivityName = activityType,
                ActivityNamespace = activityNamespace,
                RootNamespace = null,
                GenerateAsPartialClass = false,
                AlwaysGenerateSource = true,
                ForImplementation = false
            };

            // Compile the C# expression.
            TextExpressionCompilerResults results =
                new TextExpressionCompiler(settings).Compile();

            // Any compilation errors are contained in the CompilerMessages.
            if (results.HasErrors)
            {
                throw new Exception("Compilation failed.");
            }

            // Create an instance of the new compiled expression type.
            ICompiledExpressionRoot compiledExpressionRoot =
                Activator.CreateInstance(results.ResultType,
                    new object[] { activity }) as ICompiledExpressionRoot;

            // Attach it to the activity.
            CompiledExpressionInvoker.SetCompiledExpressionRoot(
                activity, compiledExpressionRoot);
        }
    }

完整的错误信息：

[System.NotSupportedException]  {System.NotSupportedException: Expression Activity type 'CSharpValue`1' requires compilation in order to run.  Please ensure that the workflow has been compiled.
   at System.Activities.Expressions.CompiledExpressionInvoker.InvokeExpression(ActivityContext activityContext)
   at Microsoft.CSharp.Activities.CSharpValue`1.Execute(CodeActivityContext context)
   at System.Activities.CodeActivity`1.InternalExecuteInResolutionContext(CodeActivityContext context)
   at System.Activities.Runtime.ActivityExecutor.ExecuteInResolutionContext[T](ActivityInstance parentInstance, Activity`1 expressionActivity)
   at System.Activities.InArgument`1.TryPopulateValue(LocationEnvironment targetEnvironment, ActivityInstance activityInstance, ActivityExecutor executor)
   at System.Activities.RuntimeArgument.TryPopulateValue(LocationEnvironment targetEnvironment, ActivityInstance targetActivityInstance, ActivityExecutor executor, Object argumentValueOverride, Location resultLocation, Boolean skipFastPath)
   at System.Activities.ActivityInstance.InternalTryPopulateArgumentValueOrScheduleExpression(RuntimeArgument argument, Int32 nextArgumentIndex, ActivityExecutor executor, IDictionary`2 argumentValueOverrides, Location resultLocation, Boolean isDynamicUpdate)
   at System.Activities.ActivityInstance.ResolveArguments(ActivityExecutor executor, IDictionary`2 argumentValueOverrides, Location resultLocation, Int32 startIndex)
   at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

Answer 1

谢谢 Maciej Los 先生。最后我从你推荐的 the article 得到了正确的方法，你的回复很有帮助..

如果以后有人需要，这里是答案。

 static void Main(string[] args)
        {
            Dictionary<string, object> inputs = new Dictionary<string, object>();            
            inputs.Add("userName", "Test User");         

            // Using DynamicActivity for this sample so that we can have an
            // InArgument, and also do everything without XAML at all
            DynamicActivity codeWorkflow = new DynamicActivity();
            codeWorkflow.Name = "MyScenario.MyDynamicActivity";
            foreach (var key in inputs.Keys)
            {
                DynamicActivityProperty property = new DynamicActivityProperty();
                property.Name = key;
                property.Type = typeof(InArgument<Dictionary<string,object>>);                
                codeWorkflow.Properties.Add(property);
            }
            codeWorkflow.Implementation = () => new WriteLine
            {
                Text = new CSharpValue<string>
                {
                    ExpressionText = "\"hello ! \" + InArguments[\"userName\"].ToString()"
                },
            };         
            Compile(codeWorkflow);
            WorkflowInvoker.Invoke(codeWorkflow,
             new Dictionary<string, object>
                {
            { "InArguments", inputs}
                });

            Console.ReadLine(); 
        }

编译方法为：

static void Compile(DynamicActivity dynamicActivity)
        {
            TextExpressionCompilerSettings settings = new TextExpressionCompilerSettings
            {
                Activity = dynamicActivity,
                Language = "C#",
                ActivityName = dynamicActivity.Name.Split('.').Last() + "_CompiledExpressionRoot",
                ActivityNamespace = string.Join(".", dynamicActivity.Name.Split('.').Reverse().Skip(1).Reverse()),
                RootNamespace = null,
                GenerateAsPartialClass = false,
                AlwaysGenerateSource = true,
            };

            TextExpressionCompilerResults results =
                new TextExpressionCompiler(settings).Compile();
            if (results.HasErrors)
            {
                throw new Exception("Compilation failed.");
            }

            ICompiledExpressionRoot compiledExpressionRoot =
                Activator.CreateInstance(results.ResultType,
                    new object[] { dynamicActivity }) as ICompiledExpressionRoot;
            CompiledExpressionInvoker.SetCompiledExpressionRootForImplementation(
                dynamicActivity, compiledExpressionRoot);
        }