Asp.net 2.0 制作最原始的TextBox控件[一](示例代码下载)

2007年01月05日 20:23:00

(一). 概述

示例制作一个与Asp.net TextBox同样功能的 TextBox control, 可以了解一下

Control底层的实现原理

(二). 代码实现

1. 核心控件生成代码文件TextBox.cs

1 1 using System;
2 2 using System.Data;
3 3 using System.Configuration;
4 4 using System.Web;
5 5 using System.Web.Security;
6 6 using System.Web.UI;
7 7 using System.Web.UI.WebControls;
8 8 using System.Web.UI.WebControls.WebParts;
9 9 using System.Web.UI.HtmlControls;
10 10
11 11 using System.Text;
12 12 using System.Collections.Specialized;
13 13
14 14 namespace KingControls
15 15 {
16 16 /**/ /// >summary<
17 17 /// Making a TextBox WebControl
18 18 /// >/summary<
19 19 public class TextBox : Control, IPostBackDataHandler // IPostBackDataHandler: 处理回发数据使用
20 20 {
21 21 public TextBox()
22 22 {
23 23 }
24 24
25 25 /**/ /// >summary<
26 26 /// 设置或获取显示文本
27 27 /// >/summary<
28 28 public string Text
29 29 {
30 30 // Web编程中要用ViewState为两次回发共享数据
31 31 get
32 32 {
33 33 String s = (String)ViewState[ " Text " ];
34 34 return ((s == null ) ? String.Empty : s);
35 35 }
36 36
37 37 set
38 38 {
39 39 ViewState[ " Text " ] = value;
40 40 }
41 41 }
42 42
43 43 /**/ /// >summary<
44 44 /// 生成呈现Html格式标记
45 45 /// >/summary<
46 46 /// >param name="writer"<>/param<
47 47 protected override void Render(HtmlTextWriter writer)
48 48 {
49 49 StringBuilder sb = new StringBuilder();
50 50 sb.Append( " >input type=/ " text/ " name= " );
51 51 sb.Append( " / "" + UniqueID + " / "" ); // 标识符，继承自基类Control
52 52 sb.Append( " value= " );
53 53
54 54 // HttpUtility.HtmlEncode 将用户输入字串转换成Html格式，主要转义用户输入的html关键字为非html关键字字符
55 55 sb.Append( " / "" + HttpUtility.HtmlEncode(Text) + " / "" );
56 56 sb.Append( " /< " );
57 57 writer.Write(sb.ToString());
58 58 }
59 59
60 60 /**/ /// >summary<
61 61 /// 当回发时，装载用户输入的新数据
62 62 /// >/summary<
63 63 /// >param name="postDataKey"<>/param<
64 64 /// >param name="postCollection"<>/param<
65 65 /// >returns< true表示数据改变,将会执行下面的方法RaisePostDataChangedEvent; 否则数据未改变 >/returns<
66 66 public virtual bool LoadPostData( string postDataKey, NameValueCollection postCollection)
67 67 {
68 68 string strOldValue = Text;
69 69 string strNewValue = postCollection[ this .UniqueID];
70 70 if ( strOldValue == null || ( strOldValue != null && ! strOldValue.Equals(strNewValue)))
71 71 {
72 72 this .Text = strNewValue;
73 73 return true ;
74 74 }
75 75 return false ;
76 76 }
77 77
78 78 /**/ /// >summary<
79 79 /// 仅当上面方法LoadPostData返回true时，此方法将会执行
80 80 /// >/summary<
81 81 public virtual void RaisePostDataChangedEvent()
82 82 {
83 83 OnTextChanged(EventArgs.Empty);
84 84 }
85 85
86 86 public event EventHandler TextChanged;
87 87 protected virtual void OnTextChanged(EventArgs e)
88 88 {
89 89 if (TextChanged != null )
90 90 {
91 91 TextChanged( this , e);
92 92 }
93 93 }
94 94 }
95 95 }
96 96

2. 前台页面文件UsingTextBoxControl.aspx代码(使用方法)

1 >% @ Page Language = " C# " AutoEventWireup = " true " CodeFile = " UsingTextBoxControl.aspx.cs " Inherits = " _Default " ValidateRequest = " false " %<
2 >% @ Register Assembly = " KingControls " Namespace = " KingControls " TagPrefix = " KSP " %<
3 . .
4 > KSP:TextBox ID = " KingTextBox " runat = " server " OnTextChanged = " KingTextBox_TextChanged " Text = "" <>/ KSP:TextBox <
5 . .
6

(三). 示例代码下载

http://www.cnblogs.com/Files/ChengKing/KingControls.rar

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