如何在 .NET 的工作流 Activity 中使用外部 class？

Question

我在 class 库中定义了一个 class：

namespace TestLib
{
    public class TestClass
    {
        public static void Test() { }
    }
}

我还在 XAML 文件中定义了一个 Activity。现在我想在 activity 中使用 InvokeMethod activity 来调用 class 中的静态方法，但调试器会抛出运行时异常：

"Could not load file or assembly 'TestLib, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified."

class 库被正确引用，我也可以在 XAML 源代码中看到它。如果我将此 class 包含到源代码中，它可以正常工作。

在工作流中使用外部类型的正确方法是什么？我做错了什么？谢谢。

更新：

重现这个案例非常简单。

创建一个名为TestLib的Class Library项目并添加上面的TestClass.

创建一个 Activity Library 项目并将 main activity 重命名为 TestActivity。添加对 TestLib 的引用。添加一个Sequence activity，里面有一个InvokeMethod activity，用来调用方法TestClass.Test。这是 XAML 代码：

<Activity mc:Ignorable="sap sap2010 sads" x:Class="WorkflowSimpleTest.TestActivity" sap2010:ExpressionActivityEditor.ExpressionActivityEditor="C#" sap2010:WorkflowViewState.IdRef="WorkflowSimpleTest.Activity1_1"
 xmlns="http://schemas.microsoft.com/netfx/2009/xaml/activities"
 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 xmlns:sads="http://schemas.microsoft.com/netfx/2010/xaml/activities/debugger"
 xmlns:sap="http://schemas.microsoft.com/netfx/2009/xaml/activities/presentation"
 xmlns:sap2010="http://schemas.microsoft.com/netfx/2010/xaml/activities/presentation"
 xmlns:scg="clr-namespace:System.Collections.Generic;assembly=mscorlib"
 xmlns:sco="clr-namespace:System.Collections.ObjectModel;assembly=mscorlib"
 xmlns:t="clr-namespace:TestLib;assembly=TestLib"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <TextExpression.NamespacesForImplementation>
    <sco:Collection x:TypeArguments="x:String">
      <x:String>System</x:String>
      <x:String>System.Collections.Generic</x:String>
      <x:String>System.Data</x:String>
      <x:String>System.Linq</x:String>
      <x:String>System.Text</x:String>
    </sco:Collection>
  </TextExpression.NamespacesForImplementation>
  <TextExpression.ReferencesForImplementation>
    <sco:Collection x:TypeArguments="AssemblyReference">
      <AssemblyReference>Microsoft.CSharp</AssemblyReference>
      <AssemblyReference>System</AssemblyReference>
      <AssemblyReference>System.Activities</AssemblyReference>
      <AssemblyReference>System.Core</AssemblyReference>
      <AssemblyReference>System.Data</AssemblyReference>
      <AssemblyReference>System.Runtime.Serialization</AssemblyReference>
      <AssemblyReference>System.ServiceModel</AssemblyReference>
      <AssemblyReference>System.ServiceModel.Activities</AssemblyReference>
      <AssemblyReference>System.Xaml</AssemblyReference>
      <AssemblyReference>System.Xml</AssemblyReference>
      <AssemblyReference>System.Xml.Linq</AssemblyReference>
      <AssemblyReference>mscorlib</AssemblyReference>
      <AssemblyReference>TestLib</AssemblyReference>
      <AssemblyReference>WorkflowSimpleTest</AssemblyReference>
    </sco:Collection>
  </TextExpression.ReferencesForImplementation>
  <Sequence sap2010:WorkflowViewState.IdRef="Sequence_1">
    <InvokeMethod sap2010:WorkflowViewState.IdRef="InvokeMethod_1" MethodName="Test" TargetType="t:TestClass" />
    <WriteLine sap2010:WorkflowViewState.IdRef="WriteLine_1" Text="End activity." />
    <sads:DebugSymbol.Symbol>d1dEOlxFbHZlZGluXFByb2plY3RzXEF1dG9tYXRpb24mQklcc291cmNlXFNFQ1VSSVRBU1xXb3JrZm9sd1NpbXBsZVRlc3RcVGVzdEFjdGl2aXR5LnhhbWwEJgMqDgIBAScFJ3ECAQQoBShVAgECKEMoUgIBAw==</sads:DebugSymbol.Symbol>
  </Sequence>
  <sap2010:WorkflowViewState.ViewStateManager>
    <sap2010:ViewStateManager>
      <sap2010:ViewStateData Id="InvokeMethod_1" sap:VirtualizedContainerService.HintSize="218,130" />
      <sap2010:ViewStateData Id="WriteLine_1" sap:VirtualizedContainerService.HintSize="218,62" />
      <sap2010:ViewStateData Id="Sequence_1" sap:VirtualizedContainerService.HintSize="240,356">
        <sap:WorkflowViewStateService.ViewState>
          <scg:Dictionary x:TypeArguments="x:String, x:Object">
            <x:Boolean x:Key="IsExpanded">True</x:Boolean>
          </scg:Dictionary>
        </sap:WorkflowViewStateService.ViewState>
      </sap2010:ViewStateData>
      <sap2010:ViewStateData Id="WorkfolwSimpleTest.Activity1_1" sap:VirtualizedContainerService.HintSize="280,436" />
    </sap2010:ViewStateManager>
  </sap2010:WorkflowViewState.ViewStateManager>
</Activity>

创建控制台应用程序并使用以下代码执行工作流：

Dictionary<string, object> vars = new Dictionary<string, object>() { };
WorkflowApplication wfApp = new WorkflowApplication(new TestActivity(), vars);
wfApp.Completed += delegate (WorkflowApplicationCompletedEventArgs e)
{
    Console.WriteLine("Completed.");
};
wfApp.Idle += delegate (WorkflowApplicationIdleEventArgs e1)
{
    Console.WriteLine("Idle.");
};
wfApp.Run();

应用程序应该抛出运行时异常。

Answer 1

错误如其所说。显然，通过在 Workflow Library 项目中添加对库的引用，我也应该在宿主项目中添加引用。

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