参考:http://kb.cnblogs.com/a/391555/
这个代码很好用,让呆板的DropDownList可以添加漂亮的样式,并且支持空格.
也很有代表性,可以让大家举一反三,灵活使用其他asp控件.
但在应用的时候,发现了一点小问题:
原作代码用(char)58853来替换" ",效果看上去是像空格,但并不是空格,如果浏览器切换编码,就会显示乱码.
为了解决这个问题,我对原代码稍做修改,就可以任意切换都不会有问题.修改后的代码如下:
using System; using System.Data; using System.Configuration; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.ComponentModel; using System.Collections; using System.Drawing; namespace reworkControl { /// <summary> /// DropDownLists的摘要说明 /// </summary> public class MyDropDownLists : DropDownList { protected override void RenderContents(HtmlTextWriter writer) { ListItemCollection listItemCollection = base.Items; int i = base.Items.Count; bool flag = false; if (i > 0) { for (int j = 0; j < i; j++) { ListItem listItem = listItemCollection[j]; writer.WriteBeginTag("option"); if (listItem.Selected) { if (flag) { throw new HttpException("Cant_Multiselect_In_DropDownList"); } flag = true; writer.WriteAttribute("selected", "selected", false); } writer.WriteAttribute("value", listItem.Value, true); System.Web.UI.AttributeCollection attributeCollection = listItem.Attributes; IEnumerator iEnumerator = attributeCollection.Keys.GetEnumerator(); while (iEnumerator.MoveNext()) { string str2 = (String)iEnumerator.Current; writer.Write(" " + str2 + "=/"" + attributeCollection[str2] + "/""); } writer.Write('>'); //start 一直到"//end",是修改的地方 //HttpUtility.HtmlEncode(listItem.Text.Replace(" ", ((char)58853).ToString()), writer); string tmp = listItem.Text.Replace(" ", "§");//这里的"§"尽量用偏僻的字符 char[] pt = tmp.ToCharArray(); for (int i = 0; i < pt.length; i++) { if (pt[i] == '§') { writer.Write(" "); } else { writer.Write(pt[i]); } } //end writer.WriteEndTag("option"); writer.WriteLine(); } } } protected override object SaveViewState() { object[] objs = new object[2]; objs[0] = base.SaveViewState(); System.Collections.ArrayList list = new ArrayList(); objs[1] = list; foreach (ListItem item in this.Items) { System.Collections.Hashtable hash = new Hashtable(); foreach (Object key in item.Attributes.Keys) { hash.Add(key, item.Attributes[key.ToString()]); } list.Add(hash); } return objs; } protected override void LoadViewState(object savedState) { object[] objs = (Object[])savedState; base.LoadViewState(objs[0]); System.Collections.ArrayList list = (System.Collections.ArrayList)objs[1]; for (int i = 0; i < list.Count; i++) { System.Collections.Hashtable hash = (System.Collections.Hashtable)list[i]; foreach (object key in hash.Keys) { Items[i].Attributes.Add(key.ToString(), hash[key].ToString()); } } } } }
下面对使用方法归纳整理下,便于初学者使用:
1> 将上面的代码单独保存为.cs文件,比如MyDropdownlist.cs
2>把文件MyDropdownlist.cs拷贝到C:/WINDOWS/Microsoft.NET/Framework/v3.5文件下
(相信大家的Framework都是3.5了, 如果不是,请选相应的文件夹).
3>运行->程序->附件->dos命令控制台,打开命令窗后,输入cd C:/WINDOWS/Microsoft.NET/Framework/v3.5,
回车进入该目录,再输入csc /t:library MyDropdownlist.cs,回车.
4>把该目录下生成的MyDropdownlist.dll拷贝到你的工程文件里面的/WEB/BIN文件夹下.
5>需要使用该MyDropdownlist控件的页面文件(.aspx)顶部添加如下代码:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="TEST.aspx.cs" Inherits="WebApplication.TEST" %> <%@ Register TagPrefix="myDDL" Namespace="reworkControl" Assembly="MyDropdownlist" %> //在这个位置添加这行代码 <!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> ... ...
6>.aspx页面调用的代码如下:
<myDDL:MyDropdownlist ID="xxx" runat="server" Width="12px" DataTextField="Name" DataValueField="Id" />
//跟调用asp原控件是一样的,<asp:dropdownlis id="xxx" runat="server" ... ... />
7>页面后台控制代码例子(照搬原例子):
protected void Page_Load(object sender, EventArgs e) { ListItem item = new ListItem(" 萧萧", "bb"); item.Attributes.Add("style", "color:#ff3939"); item.Attributes.Add("onClick", "alert('你好')"); drp.Items.Add(item); item = new ListItem(" 欢欢", "cj"); item.Attributes.Add("style", "color:#ff39ee"); item.Attributes.Add("onclick", "alert('我好')"); drp.Items.Add(item); }
相信大家都会用了吧,怎么样,知道怎么举一反三,改造其他控件来吗?
当然,不是特别需要,最好不要随便拓展控件哦.
