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ASP.NET自定义Web服务器控件-DropDownList/Select下拉列表控件

2011-08-26 00:50 696 查看

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
//自定义web服务器控件-下拉列表
namespace MyControls
{
[DefaultProperty("Text")]
[ToolboxData("<{0}:MySelect runat=server></{0}:MySelect>")]
[ParseChildren(true,"Items")] //规定
public class MySelect : WebControl
{
[Bindable(true)]
[Category("Appearance")]
[DefaultValue("")]
[Localizable(true)]
public string Text
{
get
{
String s = (String)ViewState["Text"];
return ((s == null) ? String.Empty : s);
}

set
{
ViewState["Text"] = value;
}
}
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)] //以内容的形式打印标签
public List<SelectItem> Items{
get{
if(ViewState["Items"]==null){
ViewState["Items"] = new List<SelectItem>();
}
return (List<SelectItem>)ViewState["Items"];
}
set{
ViewState["Items"] = value;
}
}

[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]//以内容的形式打印标签
public Size Size
{
get
{
if (ViewState["Size"] == null)
{
ViewState["Size"] = new Size();
}
return (Size)ViewState["Size"];
}
set
{
ViewState["Size"] = value;
}
}
public override void RenderBeginTag(HtmlTextWriter writer)
{
this.Style.Add("Width", Size.Width + "px"); //增加样式，宽度
this.Style.Add("Height", Size.Height + "px"); //增加样式，高度
base.RenderBeginTag(writer);
}
protected override HtmlTextWriterTag TagKey
{
get
{
return HtmlTextWriterTag.Select;//下拉列表标签
}
}
protected override void RenderContents(HtmlTextWriter output)
{
//打印下拉列表内容
foreach(SelectItem item in Items){
output.Write("<option value='"+item.Value+"'>"+item.Text+"</option>");
}
}
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

//<!--自定义服务器下拉列表控件的子标签
namespace MyControls
{
public class SelectItem
{
public string Value { set; get; } //选择的值
public string Text { set; get; } //选择的文本内容
public SelectItem() { }
public SelectItem(string text, string value) {
this.Text = text;
this.Value = value;
}
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

//<cc1:MyButton ID="MyButton1" Size-Height="30" Size-Width="290"  />用法，用于这种内部属性
//定义一个大小的类，里面包含了宽高
namespace MyControls
{
public class Size
{
public int Width { set; get; }
public int Height { set; get; }
public Size(int width,int height) {
this.Width = width;
this.Height = height;
}
public Size() : this(100,100) { }
}
}

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register assembly="MyControls" namespace="MyControls" tagprefix="cc1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<!--自定义服务器下拉列表控件-->
<cc1:MySelect Size-Height="100" Size-Width="100" ID="MySelect1" runat="server">
<cc1:SelectItem Value="1" Text="选择一" />
<cc1:SelectItem Value="2" Text="选择二" />
<cc1:SelectItem Value="3" Text="选择三" />
</cc1:MySelect>
</div>
</form>

</body>
</html>

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