WF。 NativeActivity内的C＃表达式 [英] WF. C# expressions inside of NativeActivity

问题描述

我正在尝试在NativeActivity内使用自定义的c＃表达式 b

它可以像简单的表达式一样工作，如 Condition = new CSharpValue（1 == 1 ）

它不适用于这样的表达式 Condition = new CSharpValue（Address == null）

由于表达式编译错误，我无法引用表达式中的活动的Variable或InArgument当前上下文中xxxxx不存在

工作代码

  var act = new ExecuteIfTrue 
 {
 Condition = new CSharpValue< Boolean>（1 == 1），
 Address = new InArgument< MailAddress>（ctx => new MailAddress {DisplayName =TestDisplayName}），
 Body = new WriteLine {Text =Rest！ } 
}; 
 
 CompileCSharpExpressions< MailAddress>（act）; 
 WorkflowInvoker.Invoke（act）; 
  

非工作代码（指的是NativeActivity的InArgument） p>

  var act = new ExecuteIfTrue 
 {
 Condition = new CSharpValue< Boolean>（Address.Email == null），
 // Condition = new CSharpValue< Boolean>（MailAddressVar == null），
 Address = new InArgument< MailAddress>（ctx => new MailAddress {DisplayName =TestDisplayName }），
 Body = new WriteLine {Text =Rest！ } 
}; 
 
 CompileCSharpExpressions< MailAddress>（act）; 
 WorkflowInvoker.Invoke（act）; 
  

NativeActivity

  public class ExecuteIfTrue：NativeActivity 
 {
 [RequiredArgument] 
 public InArgument< bool>条件{get;组; } 
 
 [RequiredArgument] 
 public InArgument< MailAddress>地址{get;组; } 
 
 public Variable< MailAddress> MailAddressVar; 
 
 public Activity Body {get;组; } 
 
 public ExecuteIfTrue（）
 {
 MailAddressVar = new Variable< MailAddress> {Default = null}; 
} 
 
 protected override void Execute（NativeActivityContext context）
 {
 if（context.GetValue（this.Condition）& amp; this.Body！= null ）
 context.ScheduleActivity（this.Body）; 
} 
 
 protected override void CacheMetadata（NativeActivityMetadata metadata）
 {
 metadata.AddImplementationVariable（MailAddressVar）; 
 base.CacheMetadata（元数据）; 
} 
} 
 
 
 public class MailAddress 
 {
 public String Email {get;组; } 
 public String DisplayName {get;组; 
} 
  

助手方法

  public static void CompileCSharpExpressions< T>（活动活动）
 {
 var impl = new AttachableMemberIdentifier（typeof（TextExpression） NamespacesForImplementation）; 
 var namespaces = new List< string> {typeof（T）.Namespace}; 
 TextExpression.SetReferencesForImplementation（activity，new AssemblyReference {Assembly = typeof（T）.Assembly}）; 
 AttachablePropertyServices.SetProperty（activity，impl，namespaces）; 
 
 var activityName = activity.GetType（）。ToString（）; 
 var activityType = activityName.Split（'。'）。Last（）+_CompiledExpressionRoot; 
 var activityNamespace = string.Join（。，activityName.Split（'。'）。Reverse（）。Skip（1）.Reverse（））; 
 
 var settings = new TextExpressionCompilerSettings 
 {
 Activity = activity，
 Language =C＃，
 ActivityName = activityType，
 ActivityNamespace = activityNamespace，
 RootNamespace = null，
 GenerateAsPartialClass = false，
 AlwaysGenerateSource = true，
 ForImplementation = false 
}; 
 
 var results = new TextExpressionCompiler（settings）.Compile（）; 
 
 if（results.HasErrors）
 {
 throw new Exception（Compilation failed。）; 
} 
 
 var compiledExpressionRoot = Activator.CreateInstance（results.ResultType，new object [] {activity}）as ICompiledExpressionRoot; 
 CompiledExpressionInvoker.SetCompiledExpressionRoot（activity，compiledExpressionRoot）; 
} 
  

解决方案

错误非常明确;您的表达式在范围中没有变量 MailAddressVar 。

原因是您需要将变量传递给表达式。 ExecuteIfTrue 活动没有变量参数。

而是尝试这样：

 变量< string> mailAddressVar = new Variable< string>（name：MailAddressVar，defaultValue：null）; 
 
活动seq = new序列
 {
变量= {mailAddressVar}，
活动= 
 {
 new ExecuteIfTrue 
 { 
 // Condition = new CSharpValue< Boolean>（Address.Email == null），
 Condition = new CSharpValue< Boolean>（MailAddressVar == null），
 Address =新的InArgument< MailAddress>（ctx => new MailAddress {DisplayName =TestDisplayName}），
 Body = new WriteLine {Text =Rest！ } 
} 
} 
}; 
 
 ExecuteIfTrue.CompileCSharpExpressions< MailAddress>（seq）; 
 WorkflowInvoker.Invoke（seq）; 
  

I am trying to use custom c# expression inside of NativeActivity

It works fine with simple expression like Condition = new CSharpValue("1 == 1")

It doesn't work with such expressions Condition = new CSharpValue("Address == null")

I cannot refer to the activity's Variable or InArgument in the expression due to expression compilation error "The name 'xxxxx' does not exist in the current context"

Working code

var act = new ExecuteIfTrue
{
    Condition = new CSharpValue<Boolean>("1 == 1"),
    Address = new InArgument<MailAddress>(ctx => new MailAddress { DisplayName = "TestDisplayName" }),
    Body = new WriteLine { Text = "Rest!" }
};

CompileCSharpExpressions<MailAddress>(act);
WorkflowInvoker.Invoke(act);

Non-Working code (refers to the InArgument of NativeActivity)

var act = new ExecuteIfTrue
{
    Condition = new CSharpValue<Boolean>("Address.Email == null"),
    //Condition = new CSharpValue<Boolean>("MailAddressVar == null"),
    Address = new InArgument<MailAddress>(ctx => new MailAddress { DisplayName = "TestDisplayName" }),
    Body = new WriteLine { Text = "Rest!" }
};

CompileCSharpExpressions<MailAddress>(act);
WorkflowInvoker.Invoke(act);

NativeActivity

public class ExecuteIfTrue : NativeActivity
{
    [RequiredArgument]
    public InArgument<bool> Condition { get; set; }

    [RequiredArgument]
    public InArgument<MailAddress> Address { get; set; }

    public Variable<MailAddress> MailAddressVar;

    public Activity Body { get; set; }

    public ExecuteIfTrue()
    {
        MailAddressVar = new Variable<MailAddress> { Default = null };
    }

    protected override void Execute(NativeActivityContext context)
    {
        if (context.GetValue(this.Condition) && this.Body != null)
            context.ScheduleActivity(this.Body);
    }

    protected override void CacheMetadata(NativeActivityMetadata metadata)
    {
        metadata.AddImplementationVariable(MailAddressVar);
        base.CacheMetadata(metadata);
    }
}


public class MailAddress
{
    public String Email { get; set; }
    public String DisplayName { get; set; }
}

Helper method

public static void CompileCSharpExpressions<T>(Activity activity)
{
    var impl = new AttachableMemberIdentifier(typeof(TextExpression), "NamespacesForImplementation");
    var namespaces = new List<string> { typeof(T).Namespace };
    TextExpression.SetReferencesForImplementation(activity, new AssemblyReference { Assembly = typeof(T).Assembly });
    AttachablePropertyServices.SetProperty(activity, impl, namespaces);

    var activityName = activity.GetType().ToString();
    var activityType = activityName.Split('.').Last() + "_CompiledExpressionRoot";
    var activityNamespace = string.Join(".", activityName.Split('.').Reverse().Skip(1).Reverse());

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

    var results = new TextExpressionCompiler(settings).Compile();

    if (results.HasErrors)
    {
        throw new Exception("Compilation failed.");
    }

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

解决方案

The error is pretty explicit; your expression does not have the variable MailAddressVar in scope.

The reason being is you need to pass the variable into the expression. The ExecuteIfTrue activity does not have a variables parameter.

Instead try something like this:

Variable<string> mailAddressVar = new Variable<string>(name: "MailAddressVar", defaultValue: null);

Activity seq = new Sequence
{
    Variables = { mailAddressVar },
    Activities = 
    {
        new ExecuteIfTrue
        {       
            //Condition = new CSharpValue<Boolean>("Address.Email == null"),
            Condition = new CSharpValue<Boolean>("MailAddressVar == null"),
            Address = new InArgument<MailAddress>(ctx => new MailAddress { DisplayName = "TestDisplayName" }),
            Body = new WriteLine { Text = "Rest!" }
        }
    }
};

ExecuteIfTrue.CompileCSharpExpressions<MailAddress>(seq);
WorkflowInvoker.Invoke(seq);

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