Asp.net 2.0 制作最原始的TextBox控件[一](示例代码下载)
(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
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using
System;
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using
System.Data;
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using
System.Configuration;
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using
System.Web;
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using
System.Web.Security;
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using
System.Web.UI;
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using
System.Web.UI.WebControls;
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using
System.Web.UI.WebControls.WebParts;
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using
System.Web.UI.HtmlControls;
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using
System.Text;
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using
System.Collections.Specialized;
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namespace
KingControls
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{
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/**/
///
<summary>
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///
Making a TextBox WebControl
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///
</summary>
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public
class
TextBox : Control, IPostBackDataHandler
//
IPostBackDataHandler: 处理回发数据使用
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{
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public
TextBox()
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{
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}
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/**/
///
<summary>
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///
设置或获取显示文本
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///
</summary>
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public
string
Text
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{
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//
Web编程中要用ViewState为两次回发共享数据
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get
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{
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String s
=
(String)ViewState[
"
Text
"
];
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return
((s
==
null
)
?
String.Empty : s);
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}
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set
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{
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ViewState[
"
Text
"
]
=
value;
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}
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}
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/**/
///
<summary>
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///
生成呈现Html格式标记
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///
</summary>
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///
<param name="writer"></param>
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protected
override
void
Render(HtmlTextWriter writer)
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{
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StringBuilder sb
=
new
StringBuilder();
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sb.Append(
"
<input type=/
"
text/
"
name=
"
);
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sb.Append(
"
/
""
+ UniqueID +
"
/
""
);
//
标识符，继承自基类Control
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sb.Append(
"
value=
"
);
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//
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
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sb.Append(
"
/
""
+ HttpUtility.HtmlEncode(Text) +
"
/
""
);
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sb.Append(
"
/>
"
);
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writer.Write(sb.ToString());
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}
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/**/
///
<summary>
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///
当回发时，装载用户输入的新数据
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///
</summary>
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///
<param name="postDataKey"></param>
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///
<param name="postCollection"></param>
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///
<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>
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public
virtual
bool
LoadPostData(
string
postDataKey, NameValueCollection postCollection)
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{
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string
strOldValue
=
Text;
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string
strNewValue
=
postCollection[
this
.UniqueID];
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if
( strOldValue
==
null
||
( strOldValue
!=
null
&&
!
strOldValue.Equals(strNewValue)))
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{
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this
.Text
=
strNewValue;
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return
true
;
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}
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return
false
;
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}
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/**/
///
<summary>
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///
仅当上面方法LoadPostData返回true时，此方法将会执行
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///
</summary>
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public
virtual
void
RaisePostDataChangedEvent()
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{
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OnTextChanged(EventArgs.Empty);
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}
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public
event
EventHandler TextChanged;
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protected
virtual
void
OnTextChanged(EventArgs e)
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{
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if
(TextChanged
!=
null
)
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{
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TextChanged(
this
, e);
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}
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}
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}
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}
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2. 前台页面文件UsingTextBoxControl.aspx代码(使用方法)
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<%
@ Page Language
=
"
C#
"
AutoEventWireup
=
"
true
"
CodeFile
=
"
UsingTextBoxControl.aspx.cs
"
Inherits
=
"
_Default
"
ValidateRequest
=
"
false
"
%>
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<%
@ Register Assembly
=
"
KingControls
"
Namespace
=
"
KingControls
"
TagPrefix
=
"
KSP
"
%>
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… …
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<
KSP:TextBox ID
=
"
KingTextBox
"
runat
=
"
server
"
OnTextChanged
=
"
KingTextBox_TextChanged
"
Text
=
""
></
KSP:TextBox
>
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… …
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(三). 示例代码下载
http://www.cnblogs.com/Files/ChengKing/KingControls.rar
