零.引言
前面一篇文章介绍了如何在PropertyGrid中添加属性Tab，本文主要介绍如何添加事件选项卡。事件在许多对象中都有，尤其是在控件中，如何让对象的事件在PropertyGrid中显示出来呢，本文将进行简单的说明。
一.回顾添加属性Tab
在上篇文章中详细的讲解了如何添加属性Tab，这里简单回顾一下：
1.新建一个Tab类并继承于PropertyTab。
2.重写TabName和Bitmap属性以及GetProperties方法。
3.给特定类添加PropertyTab特性或将自定义Tab类添加到PropertyGrid的PropertyTabs集合中。
三步就可以完成了，添加EventTab与此类似，现在问题的关键在于我们要显示的是事件，而GetProperties方法只能返回属性集合（PropertyDescriptorCollection）。怎么办呢，很简单，我们把事件封装成PropertyDescriptor，再返回就行了。
二. 添加EventTab
GetProperties方法只能返回属性集合。那我们就把事件封装成PropertyDescriptor。首先定义一个封装事件的类，该类继承于PropertyDescriptor：
1 class EventWrapper : PropertyDescriptor
2 {
3 string name; //名字
4 public EventWrapper(string name)
5 : base(name, null)
6 {
7 this.name = name;
8 }
9
10 public override bool CanResetValue(object component)
11 {
12 return true;
13 }
14
15 public override string DisplayName
16 {
17 get
18 {
19 return name;
20 }
21 }
22
23 public override string Description
24 {
25 get
26 {
27 return string.Format("{0} description", name);
28 }
29 }
30
31 public override bool IsReadOnly
32 {
33 get { return false; }
34 }
35
36 public override string Name
37 {
38 get
39 {
40 return "fs2_" + name;
41 }
42 }
43
44 public override Type ComponentType
45 {
46 get { throw new NotImplementedException(); }
47 }
48
49 public override object GetValue(object component)
50 {
51 //do something
52 return "";
53 }
54
55 public override Type PropertyType
56 {
57 get { return typeof(string); }
58 }
59
60 public override void ResetValue(object component)
61 {
62 throw new NotImplementedException();
63 }
64
65 public override void SetValue(object component, object value)
66 {
67 //do something
68 }
69
70 public override bool ShouldSerializeValue(object component)
71 {
72 return false;
73 }
74 }
继承PropertyDescriptor时，需要重写一些属性和方法。封装类中，我们定义了一个name,用来保存事件的名称。好了，现在EventWrapper是从PropertyDescriptor继承而来，可以作为GetProperties方法的返回类型了。
接下来像前一篇文章一样定义一个EventsTab选型卡类：
1 public class EventsTab : System.Windows.Forms.Design.PropertyTab
2 {
3 [BrowsableAttribute(true)]
4 // This string contains a Base-64 encoded and serialized example property tab image.
5 private string img = "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";
6
7 public override System.ComponentModel.PropertyDescriptorCollection GetProperties(object component, Attribute[] attributes)
8 {
9 //Return list of known events
10 EventDescriptorCollection events_info;
11 if (attributes == null)
12 events_info = TypeDescriptor.GetEvents(component);
13 else
14 events_info = TypeDescriptor.GetEvents(component, attributes);
15 //封装事件
16 var events = new PropertyDescriptor[events_info.Count];
17 for (int i = 0; i < events_info.Count; i++)
18 events[i] = new EventWrapper(events_info[i].Name);
19
20 return new PropertyDescriptorCollection(events);
21 }
22
23 public override string TabName
24 {
25 get { return "Events"; }
26 }
27
28 public override System.Drawing.Bitmap Bitmap
29 {
30 get
31 {
32 Bitmap bmp = new Bitmap(DeserializeFromBase64Text(img));
33
34 return bmp;
35 }
36 }
37
38 private Image DeserializeFromBase64Text(string text)
39 {
40 Image img = null;
41 byte[] memBytes = Convert.FromBase64String(text);
42 IFormatter formatter = new BinaryFormatter();
43 MemoryStream stream = new MemoryStream(memBytes);
44 img = (Image)formatter.Deserialize(stream);
45 stream.Close();
46 return img;
47 }
48 }
唯一的不同是在Getproperties方法中，我们先获取对象的事件信息，再将其封装为我们定义的事件封装类，并返回。
现在要做的就是将我们定义的EventsTab类型添加到PropertyGrid控件的PropertyTabs集合中，将MyControl对象赋值给PropertyGrid控件的SelectedObject属性，运行程序，就可以看到MyControl对象的事件列表，效果如下：
可见，事件都列出来了。
三.完整代码
下面是完整代码：
1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Text;
5 using System.Windows.Forms;
6 using System.Windows.Forms.Design;
7 using System.ComponentModel;
8 using System.ComponentModel.Design;
9 using System.Drawing;
10 using System.IO;
11 using System.Runtime.Serialization;
12 using System.Runtime.Serialization.Formatters.Binary;
13
14 namespace TestAddTab
15 {
16 //控件类
17 //[PropertyTabAttribute(typeof(MyPropertyTab), PropertyTabScope.Component)]
18 public class MyControl : System.Windows.Forms.UserControl
19 {
20 private double _angle = 90;
21
22 public MyControl()
23 {
24 }
25
26 [BrowsableAttribute(true)]
27 [Category("角度")]
28 public double Angle
29 {
30 get
31 { return _angle; }
32 set
33 { _angle = value; }
34 }
35
36
37 protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
38 {
39 e.Graphics.DrawString("The Angle is " + _angle, this.Font, Brushes.Red, 0, 0);
40 }
41 }
42
43 public class EventsTab : System.Windows.Forms.Design.PropertyTab
44 {
45 [BrowsableAttribute(true)]
46 // This string contains a Base-64 encoded and serialized example property tab image.
47 private string img = "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";
48
49
50 public override System.ComponentModel.PropertyDescriptorCollection GetProperties(object component, Attribute[] attributes)
51 {
52 //Return list of known events
53 EventDescriptorCollection events_info;
54 if (attributes == null)
55 events_info = TypeDescriptor.GetEvents(component);
56 else
57 events_info = TypeDescriptor.GetEvents(component, attributes);
58
59 var events = new PropertyDescriptor[events_info.Count];
60 for (int i = 0; i < events_info.Count; i++)
61 events[i] = new EventWrapper(events_info[i].Name);
62
63 return new PropertyDescriptorCollection(events);
64 }
65
66 public override string TabName
67 {
68 get { return "Events"; }
69 }
70
71 public override System.Drawing.Bitmap Bitmap
72 {
73 get
74 {
75 Bitmap bmp = new Bitmap(DeserializeFromBase64Text(img));
76 return bmp;
77 }
78 }
79
80 private Image DeserializeFromBase64Text(string text)
81 {
82 Image img = null;
83 byte[] memBytes = Convert.FromBase64String(text);
84 IFormatter formatter = new BinaryFormatter();
85 MemoryStream stream = new MemoryStream(memBytes);
86 img = (Image)formatter.Deserialize(stream);
87 stream.Close();
88 return img;
89 }
90 }
91
92 class EventWrapper : PropertyDescriptor
93 {
94 string name;
95 public EventWrapper(string name)
96 : base(name, null)
97 {
98 this.name = name;
99 }
100
101 public override bool CanResetValue(object component)
102 {
103 return true;
104 }
105
106 public override string DisplayName
107 {
108 get
109 {
110 return name;
111 }
112 }
113
114 public override string Description
115 {
116 get
117 {
118 return string.Format("{0} description", name);
119 }
120 }
121
122 public override bool IsReadOnly
123 {
124 get { return false; }
125 }
126
127 public override string Name
128 {
129 get
130 {
131 return "fs2_" + name;
132 }
133 }
134
135 public override Type ComponentType
136 {
137 get { throw new NotImplementedException(); }
138 }
139
140 public override object GetValue(object component)
141 {
142 //do something
143 return "";
144 }
145
146 public override Type PropertyType
147 {
148 get { return typeof(string); }
149 }
150
151 public override void ResetValue(object component)
152 {
153 throw new NotImplementedException();
154 }
155
156 public override void SetValue(object component, object value)
157 {
158 //do something
159 }
160
161 public override bool ShouldSerializeValue(object component)
162 {
163 return false;
164 }
165 }
166 }
新建Windows工程，添加该文件，在Form中拖入一个PropertyGrid控件和MyControl控件，在Form的构造函数中添加如下代码：
this.propertyGrid1.PropertyTabs.AddTabType(typeof(EventsTab));
this.propertyGrid1.SelectedObject = this.myControl1;
运行程序，查看效果。
这里只是实现了非常简单的功能，仅仅显示了控件的事件，而不能编辑，如果要达到VS那种效果，需要完善EventWrapper类。
还是那句话，个人浅见，错漏不正之处，敬请指出，万分感谢!
时间： 2024-08-05 18:10:37