本主题适用于 Windows Workflow Foundation 4。
可以在重新承载的工作流设计器中实现自定义表达式编辑器以提供更丰富且更简单的表达式编辑体验。在以下几种情况下，您可能需要使用自定义表达式编辑器：
为 IntelliSense 和重新承载的工作流设计器中的其他丰富的编辑功能提供支持。必须提供此功能，因为无法在重新承载的应用程序中使用默认的 Visual Studio 表达式编辑器。
简化业务分析用户的表达式编辑体验，使他们无需了解 Visual Basic 或处理 Visual Basic 表达式。
实现自定义表达式编辑器需要执行以下三个基本步骤：
实现 IExpressionEditorService 接口。此接口可管理表达式编辑器的创建和析构。
实现 IExpressionEditorInstance 接口。此接口将实现表达式编辑 UI。
在重新承载的工作流应用程序中发布 IExpressionEditorService。
在类库中实现自定义表达式编辑器
以下是实现 MyExpressionEditorService 库项目中包含的 IExpressionEditorService 接口的（概念证明）MyEditorService 类的代码示例。
using System;
using System.Collections.Generic;
using System.Activities.Presentation.View;
using System.Activities.Presentation.Hosting;
using System.Activities.Presentation.Model;
namespace MyExpressionEditorService
{
public class MyEditorService : IExpressionEditorService
{
public void CloseExpressionEditors()
{
}
public IExpressionEditorInstance CreateExpressionEditor(AssemblyContextControlItem assemblies, ImportedNamespaceContextItem importedNamespaces, List<ModelItem> variables, string text)
{
MyExpressionEditorInstance instance = new MyExpressionEditorInstance();
return instance;
}
public IExpressionEditorInstance CreateExpressionEditor(AssemblyContextControlItem assemblies, ImportedNamespaceContextItem importedNamespaces, List<ModelItem> variables, string text, System.Windows.Size initialSize)
{
MyExpressionEditorInstance instance = new MyExpressionEditorInstance();
return instance;
}
public IExpressionEditorInstance CreateExpressionEditor(AssemblyContextControlItem assemblies, ImportedNamespaceContextItem importedNamespaces, List<ModelItem> variables, string text, Type expressionType)
{
MyExpressionEditorInstance instance = new MyExpressionEditorInstance();
return instance;
}
public IExpressionEditorInstance CreateExpressionEditor(AssemblyContextControlItem assemblies, ImportedNamespaceContextItem importedNamespaces, List<ModelItem> variables, string text, Type expressionType, System.Windows.Size initialSize)
{
MyExpressionEditorInstance instance = new MyExpressionEditorInstance();
return instance;
}
public void UpdateContext(AssemblyContextControlItem assemblies, ImportedNamespaceContextItem importedNamespaces)
{
}
}
}
实现 MyExpressionEditorService 库项目中包含的 IExpressionEditorInstance 接口的 MyExpressionEditorInstance 类的代码。
using System;
using System.Activities.Presentation.View;
using System.Windows;
using System.Reflection;
using System.Windows.Controls;
namespace MyExpressionEditorService
{
public class MyExpressionEditorInstance : IExpressionEditorInstance
{
private TextBox textBox = new TextBox();
public bool AcceptsReturn { get; set; }
public bool AcceptsTab { get; set; }
public bool HasAggregateFocus {
get
{
return true;
}
}
public System.Windows.Controls.ScrollBarVisibility HorizontalScrollBarVisibility { get; set; }
public System.Windows.Controls.Control HostControl {
get
{
return textBox;
}
}
public int MaxLines { get; set; }
public int MinLines { get; set; }
public string Text { get; set; }
public System.Windows.Controls.ScrollBarVisibility VerticalScrollBarVisibility { get; set; }
public event EventHandler Closing;
public event EventHandler GotAggregateFocus;
public event EventHandler LostAggregateFocus;
public event EventHandler TextChanged;
public bool CanCompleteWord()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanCopy()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanCut()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanDecreaseFilterLevel()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanGlobalIntellisense()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanIncreaseFilterLevel()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanParameterInfo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanPaste()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanQuickInfo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanRedo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool CanUndo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public void ClearSelection()
{
MessageBox.Show(MethodBase.GetCurrentMethod().Name);
}
public void Close()
{
MessageBox.Show(MethodBase.GetCurrentMethod().Name);
}
public bool CompleteWord()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool Copy()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool Cut()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool DecreaseFilterLevel()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public void Focus()
{
MessageBox.Show(MethodBase.GetCurrentMethod().Name);
}
public string GetCommittedText()
{
return "Foobar";
}
public bool GlobalIntellisense()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool IncreaseFilterLevel()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool ParameterInfo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool Paste()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool QuickInfo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool Redo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
public bool Undo()
{
return (MessageBox.Show(MethodBase.GetCurrentMethod().Name, "TestEditorInstance", MessageBoxButton.YesNo) == MessageBoxResult.Yes);
}
}
}
在 WPF 项目中发布自定义表达式编辑器
以下的代码显示如何在 WPF 应用程序中重新承载设计器以及如何创建和发布 MyEditorService 服务。
using System.Windows;
using System.Windows.Controls;
using System.Activities.Presentation;
using System.Activities.Statements;
using System.Activities.Core.Presentation;
using System.Activities.Presentation.View;
using MyExpressionEditorService;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private MyEditorService expressionEditorService;
public MainWindow()
{
InitializeComponent();
new DesignerMetadata().Register();
createDesigner();
}
public void createDesigner()
{
WorkflowDesigner designer = new WorkflowDesigner();
Sequence root = new Sequence()
{
Activities = {
new Assign(),
new WriteLine()}
};
designer.Load(root);
Grid.SetColumn(designer.View, 0);
// Create ExpressionEditorService
this.expressionEditorService = new MyEditorService();
// Publish the instance of MyEditorService.
designer.Context.Services.Publish<IExpressionEditorService>(this.expressionEditorService);
MyGrid.Children.Add(designer.View);
}
}
}
说明
如果在自定义活动设计器中使用了 ExpressionTextBox 控件，则无需使用此接口来创建和销毁表达式编辑器。ExpressionTextBox 类可为您管理此过程。