自定义工作流设计器

第一部分
基础工作，建立代码结构框架
1.创建项目WorkflowDesignerControl
1.1:WorkflowView和DesignSurface，workflowView是微软提供的工作流设计API,所有的操作都要在上面进行；DesignSurface是WorkflowView的设计时支持
WorkflowView需要从中获得一些资源。
1.2:工具箱和属性窗口也要放到WorkflowDesignerControl中
 

Toolbox toolbox = new Toolbox(this);
  this.propertyGridSplitter.Panel1.Controls.Add(toolbox);
  toolbox.Dock = DockStyle.Fill;
  toolbox.BackColor = BackColor;
  toolbox.Font = WorkflowTheme.CurrentTheme.AmbientTheme.Font; 

2、在WorkflowDesignerControl加入ActivityLibrary的引用
  DesignerHostingApplication中加入ActivityLibrary和WorkflowDesignerControl的引用
  DesignerHostingApplication中加入System.Design,System.Drawing.Design,System.Workflow.Activities,System.Workflow.ComponentModel的引用

3.所有自定义的Activitie放入一个project，这样基本的代码架构就建立好了。

第二部分
winfrom中集成可编程的wf设计器
1.首先创建DesignerHostingApplication的解决方案
重命名from1.cs为DesignerShell.cs，并加入工具条
Toolstrip
 Name: toolStrip
 GripStyle: Hidden
 RenderMode: System
 Ensure the Dock property is set to Top
将WorkflowDesignControl加入toolStrip
 Name: workflowDesignerControl
 Dock: Fill
2.使设计器支持zooming
 

public void ProcessZoom(int zoomFactor)
        {
            this.workflowView.Zoom = zoomFactor;
            this.workflowView.Update();
        }

2.1:使用预定义的zoom levels 25%, 100% and 200%，zoom设计器in or out
 在DesignerShell.cs中调用ProcessZoom
 

private void zoomDropDownMenuItem_Click(object sender, EventArgs e)
        {
            if (sender is ToolStripMenuItem)
            {
                ToolStripMenuItem menuItem = (ToolStripMenuItem)sender;

                int zoomFactor = 0;

                bool result = Int32.TryParse(menuItem.Tag.ToString(), out zoomFactor);

                if (result)
                {
                    this.workflowDesignerControl.ProcessZoom(zoomFactor);
                }
            }
        }

2.2:在toolstrip中加入dropdownButton并定义属性：
  Name: zoomDropDown
  DisplayStyle: Text
  Text: Zoom
  编辑DropDownButton,加入三个Item对应Text分别为：25% ,100%,200%
  每个item分别定义name和tag，分别为;mni25PercentZoom,25;mni100PercentZoom,100;mni200PercentZoom,200;
  并定义click事件
 
3如何在wf中添加Activities(能在workflow中添加或删除Activitie，并能修改activity的属性)
1.在WorkflowDesignerControl.cs中添加自定义的工具箱
 

public WorkflowDesignerControl()
        {
            InitializeComponent();

            Toolbox toolbox = new Toolbox(this);
            this.propertyGridSplitter.Panel1.Controls.Add(toolbox);
            toolbox.Dock = DockStyle.Fill;
            toolbox.BackColor = BackColor;
            toolbox.Font = WorkflowTheme.CurrentTheme.AmbientTheme.Font; 

            WorkflowTheme.CurrentTheme.ReadOnly = false;
            WorkflowTheme.CurrentTheme.AmbientTheme.ShowConfigErrors = false;
            WorkflowTheme.CurrentTheme.ReadOnly = true;

            this.propertyGrid.BackColor = BackColor;
            this.propertyGrid.Font = WorkflowTheme.CurrentTheme.AmbientTheme.Font;

            AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
        }

2.使WorkflowDesignerControl中的工具箱运行时加载Activitie(可以是自定义的)
 在ToolBoxItems.txt中注册
 例如我有个自定义的basic Activitie,如果要把这个Activiti加入工具箱中可以在ToolBoxItems.txt中这样写
   ActivityLibrary.MessageActivity, ActivityLibrary
 运行后就可以看到工具箱中有MessageActivity
3.在设计器中选择Activity并编辑属性
 在WorkflowDesignerControl.cs中注册事件SelectionChanged
 

ISelectionService selectionService = GetService(typeof(ISelectionService)) as ISelectionService;

                    if (selectionService != null)
                    {
                        selectionService.SelectionChanged += new EventHandler(OnSelectionChanged);
                    }

  实现OnSelectionChanged事件
 

 private void OnSelectionChanged(object sender, EventArgs e)
        {
            ISelectionService selectionService = GetService(typeof(ISelectionService)) as ISelectionService;

            if (selectionService != null)
            {
                this.propertyGrid.SelectedObjects = new ArrayList(selectionService.GetSelectedComponents()).ToArray();
            }
        }

 这样，当WorkflowDesignerControl运行时，在右边下角会显示会选择所选择Activity的属性
4.使工作流设计器支持删除功能
在WorkflowDesignerControl.cs中加入方法DeleteSelected,支持在设计器中删除Activity.

public void DeleteSelected()
        {
            ISelectionService selectionService = (ISelectionService)this.GetService(typeof(ISelectionService));

            if (selectionService != null)
            {
                if (selectionService.PrimarySelection is Activity)
                {
                    Activity activity = (Activity)selectionService.PrimarySelection;

                    if (activity.Name != this.WorkflowName)
                    {
                        activity.Parent.Activities.Remove(activity);
                        this.workflowView.Update();
                    }
                }
            }
        } 

       
在界面工具条上添加Button，属性如下
  Name: btnDelete
 DisplayStyle: Text
 Text: “Remove Activity”
在click事件中写入对WorkflowDesignerControl中DeleteSelected方法的调用

private void btnDelete_Click(object sender, EventArgs e)
        {
            this.workflowDesignerControl.DeleteSelected();
        }

5.使工作流设计器实现保存，编译，运行和打开已保存工作流的功能。
在工具条上再次添加按钮名称分别为打开，保存，编译和运行,在这些按钮的事件触发程序中调用workflowDesignerControl中已经定义好的方法
5.1在workflowDesignerControl中添加方法，加载已经存在的工作流模板文件
  

 public void LoadExistingWorkflow()
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.Filter = "xoml files (*.xoml)|*.xoml|All files (*.*)|*.*";
            openFileDialog.FilterIndex = 1;
            openFileDialog.RestoreDirectory = true;

            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                using (XmlReader xmlReader = XmlReader.Create(openFileDialog.FileName))
                {
                    WorkflowMarkupSerializer serializer = new WorkflowMarkupSerializer();
                    this.workflow = (SequentialWorkflowActivity)serializer.Deserialize(xmlReader);
                    this.LoadWorkflow();

                    this.XomlFile = openFileDialog.FileName;
                    this.Text = "Designer Hosting Sample -- [" + openFileDialog.FileName + "]";
                }
            }
        }

5.2:保存功能实现
 

private void SaveFile()
        {
            if (this.XomlFile.Length != 0)
            {
                this.SaveExistingWorkflow(this.XomlFile);
            }
            else
            {
                SaveFileDialog saveFileDialog = new SaveFileDialog();
                saveFileDialog.Filter = "xoml files (*.xoml)|*.xoml|All files (*.*)|*.*";
                saveFileDialog.FilterIndex = 1;
                saveFileDialog.RestoreDirectory = true;

                if (saveFileDialog.ShowDialog() == DialogResult.OK)
                {
                    this.SaveExistingWorkflow(saveFileDialog.FileName);
                    this.Text = "Designer Hosting Sample -- [" + saveFileDialog.FileName + "]";
                }
            }
        }

5.3:编译功能实现
 

public bool Compile()
        {
            return this.Compile(true);
        }

 public bool Compile(bool showMessage)
 {
     if (!this.Save(false))
     {
         return false;
     }

     if (!File.Exists(this.XomlFile))
     {
         MessageBox.Show(this, "Cannot locate xoml file: " + Path.Combine(Path.GetDirectoryName(this.GetType().Assembly.Location), XomlFile), this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error);
         return false;
     }

     bool compileOK = true;

     Cursor cursor = this.Cursor;
     this.Cursor = Cursors.WaitCursor;

     try
     {
         // Compile the workflow
         String[] assemblyNames = { AdditionalAssembies };
         WorkflowCompiler compiler = new WorkflowCompiler();
         WorkflowCompilerParameters parameters = new WorkflowCompilerParameters(assemblyNames);
         parameters.LibraryPaths.Add(Path.GetDirectoryName(typeof(ActivityLibrary.MessageActivity).Assembly.Location));
         parameters.GenerateInMemory = true;
         WorkflowCompilerResults compilerResults = compiler.Compile(parameters, this.XomlFile);

         inMemoryAssembly = compilerResults.CompiledAssembly;

         StringBuilder errors = new StringBuilder();

         foreach (CompilerError compilerError in compilerResults.Errors)
         {
             errors.Append(compilerError.ToString() + '\n');
         }

         if (errors.Length != 0)
         {
             MessageBox.Show(this, errors.ToString(), this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error);
             compileOK = false;
         }
         else if (showMessage)
         {
             MessageBox.Show(this, "Workflow compiled successfully. Compiled assembly:\n" + compilerResults.CompiledAssembly.GetName(), this.Text, MessageBoxButtons.OK, MessageBoxIcon.Information);
         }
     }
     finally
     {
         this.Cursor = cursor;
     }

     return compileOK;
 }

注意：
parameters.GenerateInMemory = true;这时assembly只在内存中生成，不输出到文件
如果要生成.dll文件，需要修改为
parameters.GenerateInMemory = false;
parameters.OutputAssembly = string.Format("{0}.dll", this.WorkflowName);
 
6:在工具条的事件中调用这些方法
测试一下
如果还没有保存，运行后会先保存并编译。

补传 本文所示代码:demo