pandc.cs

测试控件 测试控件

using System;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ComponentModel;
using System.Collections;
using System.Collections.Specialized;
using System.Xml;

namespace WebControlLibrary
{
	/// <summary>
	/// PandC 的摘要说明。
	/// 省市联动选择控件
	/// </summary>
	
	[DefaultProperty("Text"),ToolboxData("<{0}:PandC runat=server></{0}:PandC>")]
	public class PandC :  System.Web.UI.WebControls.WebControl, IPostBackDataHandler
	{
		#region 属性

		[Bindable(true), 
		Category("Appearance"), 
		DefaultValue("")] 
		public string Text 
		{
			get
			{
				if (ViewState["Text"] != null)
				{
					return ViewState["Text"].ToString();
				}
				else
				{
					return null;
				}
			}
			set
			{
				ViewState["Text"] = value;
			}
		}

		#endregion

		//省份
		private ArrayList parr = new ArrayList();
		//城市
		private ArrayList carr = new ArrayList();
		
		/// <summary>
		/// 将此控件呈现给指定的输出参数
		/// </summary>
		/// <param name="writer"> 要写出到的 HTML 编写器</param>
		protected override void Render(HtmlTextWriter output)
		{
			GetPandC();

			#region	省市连选所需的javascript函数

			if(!this.Page.IsClientScriptBlockRegistered("PandC_clientScript"))
			{
				output.WriteLine("<script language=\"JavaScript\">");
				output.WriteLine("var groups="+(parr.Count+1)+";");
				output.WriteLine("var group=new Array(groups);");
				output.WriteLine("for (i=0; i<groups; i++)");
				output.WriteLine("group[i]=new Array();");
				//选项0对应二级下拉框
				output.WriteLine("group[0][0]=new Option(\"请选择\",\"\");");
				for(int i=0;i<carr.Count;i++)
				{
					ArrayList arr = (ArrayList)carr[i];
					output.WriteLine("group["+(i+1)+"][0]=new Option(\"请选择\",\""+parr[i].ToString()+"\");");
					for(int j=0;j<arr.Count;j++)
					{
						output.WriteLine("group["+(i+1)+"]["+(j+1)+"]=new Option(\""+arr[j].ToString()+"\",\""+parr[i].ToString()+arr[j].ToString()+"\");");
					}
				}
				output.WriteLine("function redirectff(x,obj){");						  
				output.WriteLine("for (m=obj.options.length-1;m>0;m--)");
				output.WriteLine("obj.options[m]=null;");
				output.WriteLine("for (i=0;i<group[x].length;i++){");
				output.WriteLine("obj.options[i]=new Option(group[x][i].text,group[x][i].value);");
				output.WriteLine("obj.options[0].selected=true;");
				output.WriteLine("}}");
				output.WriteLine("</script>");
				this.Page.RegisterClientScriptBlock("PandC_clientScript", "");
			}

			#endregion

			#region 写select部分

			//初始化
			output.Write("<select id=\"" + this.ID + "_p\" name=\""+this.ID+"_p\" onChange=\"redirectff(this.options.selectedIndex,document.all."+this.ID+")\" ");
			//select的其他属性(如何将WebControl的属性很方便的全部应用到控件中呢)
			if (this.CssClass != "")
			{
				output.Write(" class=\""+this.CssClass+"\"");
			}
			output.Write(">");
			//option
			output.Write("<option>请选择</option>");
			//找出初始选定的省
			int pindex = 0;
			for (int i=0;i<parr.Count;i++)
			{
				if(this.Text != null)
				{
					//根据选定值给出默认项
					if (this.Text.IndexOf(parr[i].ToString())>-1)
					{
						output.Write("<option selected>"+parr[i].ToString()+"</option>");
						pindex = i+1;
					}
					else
					{
						output.Write("<option>"+parr[i].ToString()+"</option>");
					}
				}
				else
				{
					output.Write("<option>"+parr[i].ToString()+"</option>");
				}
				
			}
			output.Write("</select>");
			output.Write("省");
			output.Write("<select id=\""+this.ID+"\" name=\""+this.ID+"\"");
			if (this.CssClass != "")
			{
				output.Write(" class=\""+this.CssClass+"\"");
			}
			output.Write(">");
			output.Write("<option value=\"\">请选择</option>");
			//根据初始化选定的省来选定市
			if (pindex > 0)
			{
				ArrayList arr = (ArrayList)carr[pindex];
				for(int i=0;i<arr.Count;i++)
				{
				}
			}
			output.Write("</select>");
			output.Write("市");

			#endregion
		}

		/// <summary>
		/// 从XML文件中读取省份城市信息
		/// </summary>
		/// <returns></returns>
		private void GetPandC()
		{
			ArrayList arr = new ArrayList();

			//从资源中获取
			System.Reflection.Assembly thisExe;
			thisExe = System.Reflection.Assembly.GetExecutingAssembly();
			System.IO.Stream file = thisExe.GetManifestResourceStream("WebControlLibrary.PandC.xml");
			XmlTextReader xr = new XmlTextReader(file);

			while(xr.Read())
			{
				if(xr.NodeType == XmlNodeType.Element && xr.Name == "province")
				{
					parr.Add(xr.GetAttribute("name"));
					arr = new ArrayList();
				}
				if(xr.NodeType == XmlNodeType.Element && xr.Name == "city")
				{
							arr.Add(xr.GetAttribute("name"));
				}
				if(xr.NodeType == XmlNodeType.EndElement && xr.Name == "province")
				{
					carr.Add(arr);

				}
			}
			xr.Close();
		}

		#region IPostBackDataHandler 成员

		public event EventHandler TextChanged;

		/// <summary>
		/// 当由类实现时，用信号要求服务器控件对象通知 ASP.NET 应用程序该控件的状态已更改。
		/// </summary>
		public virtual void RaisePostDataChangedEvent() 
		{
			OnTextChanged(EventArgs.Empty);
		}
      

		protected virtual void OnTextChanged(EventArgs e) 
		{
			if (TextChanged != null)
				TextChanged(this,e);
		}

		/// <summary>
		/// 当由类实现时，为 ASP.NET 服务器控件处理回发数据。
		/// </summary>
		/// <param name="postDataKey">控件的主要标识符</param>
		/// <param name="postCollection">所有传入名称值的集合</param>
		/// <returns>如果服务器控件的状态在回发发生后更改，则为 true；否则为 false。</returns>
		public virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection) 
		{
			String presentValue = Text;
			String postedValue = postCollection[postDataKey];

			if (presentValue == null || !presentValue.Equals(postedValue)) 
			{
				Text = postedValue;
				return true;
			}

			return false;
		}

		#endregion
	}
}