WinForm: Custom Control's Custom Designer and Smart Tag

要给自定义控件加上自定义的设计器, 首先得写个Designer类, 比如下面的StackPanelDesigner:

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms.Design;
using System.ComponentModel.Design;

namespace Dah.Framework.Windows.Design
{
    internal class StackPanelDesigner : ParentControlDesigner // 这个类在System.Design.dll里, 一般的控件Designer可以继承ControlDesigner..
    {
        DesignerActionListCollection _actionLists;

        public override SelectionRules SelectionRules
        {
            get
            {
                if (TheStackPanel.AutoSize) // 如果AutoSize
                {
                    return SelectionRules.Moveable; // 则只能移动, 不能手动改变大小
                }
                else // 否则可以改变大小
                {
                    return SelectionRules.Moveable | SelectionRules.AllSizeable; 
                }
            }
        }

        public override System.ComponentModel.Design.DesignerActionListCollection ActionLists
        {
            get
            {
                if (_actionLists == null)
                {
                    _actionLists = new DesignerActionListCollection();
                    // 给 Smart Tag 添加 StackPanelActionList 里的选项
                    _actionLists.Add(new StackPanelActionList(this.Component));
                    // 给 Smart Tag 添加 LinearGradientPanelActionList 里的选项 , 因为 StackPanel 继承了 LinearGradientPanel 
                    _actionLists.Add(new LinearGradientPanelActionList(this.Component));
                }
                return _actionLists;
            }
        }

        private StackPanel TheStackPanel
        {
            get
            {
                return (StackPanel)Control; // Designer 所 Design 的 Control
            }
        }
    }
}

如果要加上自己的SmartTag就还得写ActionList类, 如下面的StackPanelActionList:

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;

namespace Dah.Framework.Windows.Design
{
    /// <summary>
    /// 定义了 StackPanel 的 Smart Tag 选项
    /// </summary>
    internal class StackPanelActionList : DesignerActionList
    {
        private StackPanel _stackPanel;

        public StackPanelActionList(IComponent component)
            : base(component)
        {
            this._stackPanel = component as StackPanel;
        }

        private PropertyDescriptor GetPropertyByName(String propName)
        {
            PropertyDescriptor prop;
            prop = TypeDescriptor.GetProperties(_stackPanel)[propName];
            if (null == prop)
                throw new ArgumentException("Matching StackPanel property not found!", propName);
            else
                return prop;
        }

        private void SetValue(string propertyName, object value)
        {
            GetPropertyByName(propertyName).SetValue(_panel, value);
        }

        //要有哪些属性的选项, 都得这样写一遍
        public bool AutoSize
        {
            get { return _stackPanel.AutoSize; }
            set { SetValue("AutoSize", value); }
        }

        public bool CenterAlign
        {
            get { return _stackPanel.CenterAlign; }
            set { SetValue("CenterAlign", value); }
        }

        public StackPanelOrientation Orientation
        {
            get { return _stackPanel.Orientation; }
            set { SetValue("Orientation", value); }
        }

        //这个方法在下面用到了, 可以用来调用控件的方法
        public void RefreshChildrenPosition()
        {
            _stackPanel.RefreshChildrenPosition();
        }

        //这个方法指定了Smart Tag到底有哪些选项
        public override DesignerActionItemCollection GetSortedActionItems()
        {
            DesignerActionItemCollection items = new DesignerActionItemCollection();

            string headerName = "StackPanel Options";

            //添加一个选项 Category
            items.Add(new DesignerActionHeaderItem(headerName));

            //下面的各种选项都属于这个Category, 用headerName来指定
            items.Add(new DesignerActionPropertyItem("AutoSize", "Auto Size", headerName));
            items.Add(new DesignerActionPropertyItem("CenterAlign", "Center Align", headerName));
            items.Add(new DesignerActionPropertyItem("Orientation", "Orientation", headerName));

            //上面三个都是控件属性的设置, 这个则可以给Smart Tag添加一个LinkButton来执行某些方法
            //this, 说明了"RefreshChildrenPosition"这个方法在这个类中实现
            items.Add(new DesignerActionMethodItem(this, "RefreshChildrenPosition", "Refresh children position", headerName));

            return items;
        }
    }
}

准备工作完毕, 给自定义控件加个DesignerAttribute就O了~:

    [Designer(typeof(Dah.Framework.Windows.Design.StackPanelDesigner))]
    public class StackPanel : LinearGradientPanel
    {
        public event EventHandler ContentMarginChanged;

看看我们美丽的自定义Designer和Smart Tag吧~

久不发文... 仅此灌水一篇~
更多的有关如何扩展控件设计时行为的文章在MSDN Library:
http://msdn2.microsoft.com/en-us/library/37899azc.aspx