使用自定义表达式编辑器

项目
04/07/2023

可以实现自定义表达式编辑器，以提供更丰富或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。此接口实现针对表达式编辑 UI 的 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 MyEditorService 接口的（概念证明）IExpressionEditorService 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)  
        {  
  
        }  
  
    }  
}

下面是实现 MyExpressionEditorService 库项目中 MyExpressionEditorInstance 接口的 IExpressionEditorInstance 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 "CommittedText";  
        }  
        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。使用此代码之前, 从包含 avalon2 应用程序的项目将引用添加到 MyExpressionEditorService 库项目。

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

如果正在自定义活动设计器中使用 ExpressionTextBox 控件，则无需使用 IExpressionEditorService 接口的 CreateExpressionEditor 和 CloseExpressionEditors 方法来创建和销毁表达式编辑器。 ExpressionTextBox 类可为您管理此过程。

使用自定义表达式编辑器

在类库中实现自定义表达式编辑器

在 WPF 项目中发布自定义表达式编辑器

说明

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