C#WinForm设计时编程【4】响应鼠标事件

在设计器中，先看效果：

1、鼠标离开

2、鼠标进入（手形光标没截出来）

3、鼠标单击

代码及其分析：

引用命名空间：

using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.Design;
using System.Windows.Forms.Design.Behavior;

第一步：定义一个行为类EventBehavior，这个类继承了Behavior，对需要处理的事件进行重写，用于处理鼠标事件，代码很简单，就不需要解释了，代码如下：

    class EventBehavior : Behavior
    {
        bool isPressed = false;
        Control control;

        public EventBehavior(Control control)
        {
            this.control = control;
        }

        public override bool OnMouseDown(Glyph g, MouseButtons button, Point mouseLoc)
        {
            isPressed = true;
            return true;
        }

        public override bool OnMouseUp(Glyph g, MouseButtons button)
        {
            if (isPressed) 
                OnClick();

            isPressed = false;
            return true;
        }

        public override bool OnMouseEnter(Glyph g)
        {
            this.control.BackColor = Color.LightPink;
            return true;
        }

        public override bool OnMouseLeave(Glyph g)
        {
            this.control.BackColor = Color.FromKnownColor(KnownColor.Control);
            return true;
        }

        public void OnClick()
        {
            MessageBox.Show("你单击了我！");
        }
    }

第二步：定义一个EventGlyph类，这个类继承Glyph，实现自定义控件的选择和图像处理，代码如下：

class EventGlyph : Glyph
     {
         Control control;
         BehaviorService behaviorSvc;
 
         public EventGlyph(BehaviorService behaviorSvc, Control control)
             : base(new EventBehavior(control))
         {
             this.behaviorSvc = behaviorSvc;
             this.control = control;
         }
 
         public override Rectangle Bounds
         {
             get
             {
                 Point edge = behaviorSvc.ControlToAdornerWindow(control);
                 Size size = control.Size;
                 Rectangle bounds = new Rectangle(edge.X, edge.Y, size.Width, size.Height);
 
                 return bounds;
             }
         }
 
         public override Cursor GetHitTest(System.Drawing.Point p)
         {
             if (this.Bounds.Contains(p))
             {
                 return Cursors.Hand;
             }
 
             return null;
         }
 
         public override void Paint(PaintEventArgs pe)
         {
             TextFormatFlags sf = TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter | TextFormatFlags.EndEllipsis;
             TextRenderer.DrawText(pe.Graphics, "设计时响应鼠标单击事件哦", this.control.Font, this.Bounds, Color.DarkBlue, Color.Transparent, sf);
         }

第三步：定义一个设计器EventControlDesigner，它将行为和绘制部分的内容绑定在设计器中，代码如下：

    public class EventControlDesigner : ScrollableControlDesigner
    {
        private ISelectionService SelectionService
        {
            get
            {
                return this.GetService(typeof(ISelectionService)) as ISelectionService;
            }
        }

        public override GlyphCollection GetGlyphs(GlyphSelectionType selectionType)
        {
            GlyphCollection glyphs = base.GetGlyphs(selectionType);
            if (SelectionService != null)
            {
                if (SelectionService.PrimarySelection == this.Control)
                    glyphs.Add(new EventGlyph(this.BehaviorService, this.Control));
            }
            return glyphs;
        }
    }

 第四步：在自定义控件上使用设计器，代码如下：

    [Designer(typeof(EventControlDesigner))]
    class EventControl:System.Windows.Forms.Control
    {
    }

至此为止，一个可以在设计时响应鼠标事件的控件可以运行了。