扩展Label控件(1) – 实现回发(Postback)功能 [源码下载]
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Label控件既强大又好用。为了让它更强大、更好用，我们来写一个继承自Label的控件。
介绍
扩展Label控件：
通过注册HiddenField控件，使Label控件支持回发(Postback)功能
使用方法（设置属性）：
EnablePostback – 是否启用Label控件的回发(Postback)
HiddenFieldPostfix – 使Label支持回发(Postback)的隐藏控件的后缀名
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关键代码
ScriptLibrary.js
//—————————-
// http://webabcd.cnblogs.com/
//—————————-
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function yy_sl_copyTextToHiddenField(source, destination)
{
///
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document.getElementById(destination).value = document.getElementById(source).innerHTML;
}
SmartLabel.cs
using System;
using System.Collections.Generic;
using System.Text;
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using System.Web.UI.WebControls;
using System.Web.UI;
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[assembly: System.Web.UI.WebResource("YYControls.SmartLabel.Resources.ScriptLibrary.js", "text/javascript")]
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namespace YYControls
{
/**////
/// SmartLabel类，继承自DropDownList
///
[ToolboxData(@"<{0}:SmartLabel runat=\'server\'>")]
[System.Drawing.ToolboxBitmap(typeof(YYControls.Resources.Icon), "SmartLabel.bmp")]
public partial class SmartLabel : Label
{
/**////
/// 构造函数
///
public SmartLabel()
{
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}
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/**////
/// OnPreRender
///
/// e
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
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// 实现Label控件的回发(Postback)功能
ImplementPostback();
}
}
}
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Property.cs
using System;
using System.Collections.Generic;
using System.Text;
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using System.ComponentModel;
using System.Web.UI;
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namespace YYControls
{
/**////
/// SmartLabel类的属性部分
///
public partial class SmartLabel
{
/**////
/// 使Label支持回发(Postback)的隐藏控件的后缀名
///
[
Browsable(true),
Description("使Label支持回发(Postback)的隐藏控件的后缀名"),
Category("扩展"),
DefaultValue("EnablePostback")
]
public virtual string HiddenFieldPostfix
{
get
{
string s = (string)ViewState["HiddenFieldPostfix"];
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return (s == null) ? “EnablePostback” : s;
}
set
{
ViewState["HiddenFieldPostfix"] = value;
}
}
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/**////
/// 是否启用Label控件的回发(Postback)
///
[
Browsable(true),
Description("是否启用Label控件的回发(Postback)"),
Category("扩展"),
DefaultValue(false)
]
public virtual bool EnablePostback
{
get
{
bool? b = (bool?)ViewState["EnablePostback"];
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return (b == null) ? false : (bool)b;
}
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set
{
ViewState["EnablePostback"] = value;
}
}
}
}
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EnablePostback.cs
using System;
using System.Collections.Generic;
using System.Text;
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using System.Data;
using System.Web.UI.WebControls;
using System.Web.UI;
using System.Web;
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namespace YYControls
{
/**////
/// SmartLabel类的属性部分
///
public partial class SmartLabel
{
/**////
/// 实现Label控件的回发(Postback)功能
///
private void ImplementPostback()
{
if (this.EnablePostback)
{
// 使Label支持回发(Postback)的隐藏控件的ID
string hiddenFieldId = string.Concat(this.ClientID, “_”, HiddenFieldPostfix);
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// 注册隐藏控件
Page.ClientScript.RegisterHiddenField(hiddenFieldId, “”);
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// 注册客户端脚本
this.Page.ClientScript.RegisterClientScriptResource(this.GetType(),
“YYControls.SmartLabel.Resources.ScriptLibrary.js”);
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// 表单提交前将Label控件的的值赋给隐藏控件
this.Page.ClientScript.RegisterOnSubmitStatement(this.GetType(),
“yy_sl_enablePostback”,
string.Format(“yy_sl_copyTextToHiddenField(‘{0}’, ‘{1}’)”,
this.ClientID,
hiddenFieldId));
}
}
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/**////
/// 获取或设置 YYControls.SmartLabel 控件的文本内容
///
public override string Text
{
get
{
try
{
if (this.EnablePostback && !string.IsNullOrEmpty(HttpContext.Current.Request[string.Concat(this.ClientID, "_", HiddenFieldPostfix)]))
{
// 隐藏控件的值
return HttpContext.Current.Request[string.Concat(this.ClientID, "_", HiddenFieldPostfix)];
}
else
{
return base.Text;
}
}
catch
{
return base.Text;
}
}
set
{
try
{
if (this.EnablePostback && !string.IsNullOrEmpty(HttpContext.Current.Request[string.Concat(this.ClientID, "_", HiddenFieldPostfix)]))
{
// 隐藏控件的值
base.Text = HttpContext.Current.Request[string.Concat(this.ClientID, "_", HiddenFieldPostfix)];
}
else
{
base.Text = value;
}
}
catch
{
base.Text = value;
}
}
}
}
}
作者：webabcd 来源:http://www.cnblogs.com/webabcd