扩展Label控件(1) - 实现回发(Postback)功能

来源：http://webabcd.cnblogs.com

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

关键代码
ScriptLibrary.js


//----------------------------


// http://webabcd.cnblogs.com/

//----------------------------




function yy_sl_copyTextToHiddenField(source, destination)






{


/// <summary>将Label控件的的值赋给隐藏控件</summary>




document.getElementById(destination).value = document.getElementById(source).innerHTML;


}

SmartLabel.cs


using System;


using System.Collections.Generic;


using System.Text;




using System.Web.UI.WebControls;


using System.Web.UI;




[assembly: System.Web.UI.WebResource("YYControls.SmartLabel.Resources.ScriptLibrary.js", "text/javascript")]




namespace YYControls






{




/**//// <summary>


/// SmartLabel类，继承自DropDownList


/// </summary>


[ToolboxData(@"<{0}:SmartLabel runat='server'></{0}:SmartLabel>")]


[System.Drawing.ToolboxBitmap(typeof(YYControls.Resources.Icon), "SmartLabel.bmp")]


public partial class SmartLabel : Label






{




/**//// <summary>


/// 构造函数


/// </summary>


public SmartLabel()






{




}






/**//// <summary>


/// OnPreRender


/// </summary>


/// <param name="e">e</param>


protected override void OnPreRender(EventArgs e)






{


base.OnPreRender(e);




// 实现Label控件的回发(Postback)功能


ImplementPostback();


}


}


}



Property.cs


using System;


using System.Collections.Generic;


using System.Text;




using System.ComponentModel;


using System.Web.UI;




namespace YYControls






{




/**//// <summary>


/// SmartLabel类的属性部分


/// </summary>


public partial class SmartLabel






{




/**//// <summary>


/// 使Label支持回发(Postback)的隐藏控件的后缀名


/// </summary>


[


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"];




return (s == null) ? "EnablePostback" : s;


}


set






{


ViewState["HiddenFieldPostfix"] = value;


}


}






/**//// <summary>


/// 是否启用Label控件的回发(Postback)


/// </summary>


[


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"];




return (b == null) ? false : (bool)b;


}




set






{


ViewState["EnablePostback"] = value;


}


}


}


}



EnablePostback.cs


using System;


using System.Collections.Generic;


using System.Text;




using System.Data;


using System.Web.UI.WebControls;


using System.Web.UI;


using System.Web;




namespace YYControls






{




/**//// <summary>


/// SmartLabel类的属性部分


/// </summary>


public partial class SmartLabel






{




/**//// <summary>


/// 实现Label控件的回发(Postback)功能


/// </summary>


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);




// 注册隐藏控件


Page.ClientScript.RegisterHiddenField(hiddenFieldId, "");




// 注册客户端脚本


this.Page.ClientScript.RegisterClientScriptResource(this.GetType(),


"YYControls.SmartLabel.Resources.ScriptLibrary.js");




// 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));


}


}






/**//// <summary>


/// 获取或设置 YYControls.SmartLabel 控件的文本内容


/// </summary>


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;


}


}


}


}


}



OK
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