上一篇:
宿主工作流设计器（二）
接着说我们宿主工作流设计器的话题，本节我们讲讲定制一个工具箱，允许从其中拖放工作流活动到我们的设计器当中，以及上下文菜单的定制。
记得上一篇我们取得WorkFlowView的代码吗？有这么一段：
IDesignerHost designerHost = designSurface.GetService(typeof(IDesignerHost)) as IDesignerHost;
我们看看desingerHost,它其实是整个工作流组建中的服务容器，里面承载了各种工作流设计器所需的服务，上一篇说
DesignSurface也起到服务容器的作用，确切的说
DesignSurface是desingerHost的上级容器，我们如果了解微软的Container/Componenet/Service设计思想就应该知道，下级容器会向上级容器提供服务，而注册点应该是一致的，我们可以看看整个设计器的架构图就清楚了。
我们的工具箱拖放功能其实也是以服务的形式放到desingerHost中，而要使得工作流设计器支持这个功能，必须提供一个实现
IToolboxService接口的服务类，然后调用designerHost.AddService方法注册到designerHost中，当然这个类必须以组件(Component)形式存在，以便我们把它作为工具箱放到我们自己的UI中。
下面是MSDN文章中一个工作流工具箱的实现：
ToolboxService
namespace WorkflowDesignerControl
{
using System.Runtime.Serialization.Formatters.Binary;
using System.Collections;
using System.ComponentModel.Design;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Diagnostics;
using System.Drawing.Design;
using System.Drawing.Text;
using System.Drawing;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Runtime.Remoting;
using System.Runtime.Serialization.Formatters;
using System.Text;
using System.Windows.Forms.ComponentModel;
using System.Windows.Forms.Design;
using System.Windows.Forms;
using System;
using System.Workflow.Activities;
using System.Workflow.ComponentModel;
using System.Workflow.ComponentModel.Design;
Class Toolbox#region Class Toolbox
/**//// <summary>
/// Class implementing the toolbox functionality in the sample.
/// Toolbox displays workflow components using which the workflow can be created
/// For more information on toolbox please refer to IToolboxService, ToolboxItem documentation
///
/// </summary>
[ToolboxItem(false)]
public class ToolboxService: Panel, IToolboxService
{
private const string CF_DESIGNER = "CF_WINOEDESIGNERCOMPONENTS";
private IServiceProvider provider;
private Hashtable customCreators;
private Type currentSelection;
private ListBox listBox = new ListBox();
//Create the toolbox and add the toolbox entries
public ToolboxService(IServiceProvider provider)
{
this.provider = provider;
Text = "Toolbox";
Size = new System.Drawing.Size(224, 350);
listBox.Dock = DockStyle.Fill;
listBox.IntegralHeight = false;
listBox.ItemHeight = 20;
listBox.DrawMode = DrawMode.OwnerDrawFixed;
listBox.BorderStyle = System.Windows.Forms.BorderStyle.None;
listBox.BackColor = SystemColors.Window;
listBox.ForeColor = SystemColors.ControlText;
listBox.MouseMove +=new MouseEventHandler(OnListBoxMouseMove);
Controls.Add(listBox);
listBox.DrawItem += new DrawItemEventHandler(this.OnDrawItem);
listBox.KeyPress += new KeyPressEventHandler(this.OnListKeyPress);
listBox.SelectedIndexChanged += new EventHandler(this.OnListBoxClick);
listBox.DoubleClick += new EventHandler(this.OnListBoxDoubleClick);
AddToolboxEntries(listBox);
}
public void AddCreator(ToolboxItemCreatorCallback creator, string format)
{
AddCreator(creator, format, null);
}
public void AddCreator(ToolboxItemCreatorCallback creator, string format, IDesignerHost host)
{
if (creator == null || format == null)
{
throw new ArgumentNullException(creator == null ? "creator" : "format");
}
if (customCreators == null)
{
customCreators = new Hashtable();
}
else
{
string key = format;
if (host != null) key += ", " + host.GetHashCode().ToString();
if (customCreators.ContainsKey(key))
{
throw new Exception("There is already a creator registered for the format '" + format + "'.");
}
}
customCreators[format] = creator;
}
public void AddLinkedToolboxItem(ToolboxItem toolboxItem, IDesignerHost host)
{
}
public void AddLinkedToolboxItem(ToolboxItem toolboxItem, string category, IDesignerHost host)
{
}
public virtual void AddToolboxItem(ToolboxItem toolboxItem)
{
}
public virtual void AddToolboxItem(ToolboxItem toolboxItem, IDesignerHost host)
{
}
public virtual void AddToolboxItem(ToolboxItem toolboxItem, string category)
{
}
public virtual void AddToolboxItem(ToolboxItem toolboxItem, string category, IDesignerHost host)
{
}
public CategoryNameCollection CategoryNames
{
get
{
return new CategoryNameCollection(new string[] { "Workflow" });
}
}
public string SelectedCategory
{
get
{
return "Workflow";
}
set
{
}
}
private ToolboxItemCreatorCallback FindToolboxItemCreator(IDataObject dataObj, IDesignerHost host, out string foundFormat)
{
foundFormat = string.Empty;
ToolboxItemCreatorCallback creator = null;
if (customCreators != null)
{
IEnumerator keys = customCreators.Keys.GetEnumerator();
while (keys.MoveNext())
{
string key = (string)keys.Current;
string[] keyParts = key.Split(new char[] { ',' });
string format = keyParts[0];
if (dataObj.GetDataPresent(format))
{
// Check to see if the host matches.
if (keyParts.Length == 1 || (host != null && host.GetHashCode().ToString().Equals(keyParts[1])))
{
creator = (ToolboxItemCreatorCallback)customCreators[format];
foundFormat = format;
break;
}
}
}
}
return creator;
}
public virtual ToolboxItem GetSelectedToolboxItem()
{
ToolboxItem toolClass = null;
if (this.currentSelection != null)
{
try
{
toolClass = ToolboxService.GetToolboxItem(this.currentSelection);
}
catch (TypeLoadException)
{
}
}
return toolClass;
}
public virtual ToolboxItem GetSelectedToolboxItem(IDesignerHost host)
{
return GetSelectedToolboxItem();
}
public object SerializeToolboxItem(ToolboxItem toolboxItem)
{
DataObject dataObject = new DataObject();
dataObject.SetData(typeof(ToolboxItem), toolboxItem);
return dataObject;
}
public ToolboxItem DeserializeToolboxItem(object dataObject)
{
return DeserializeToolboxItem(dataObject, null);
}
public ToolboxItem DeserializeToolboxItem(object data, IDesignerHost host)
{
IDataObject dataObject = data as IDataObject;
if (dataObject == null)
{
return null;
}
ToolboxItem t = (ToolboxItem)dataObject.GetData(typeof(ToolboxItem));
if (t == null)
{
string format;
ToolboxItemCreatorCallback creator = FindToolboxItemCreator(dataObject, host, out format);
if (creator != null)
{
return creator(dataObject, format);
}
}
ret