很久没有写ASP.NET了，今天有看到论坛上一个问题：
"两个dropDownList和一个GridView，已经进行了数据绑定，现在想让第一个下拉菜单的数据改变时，第二个下拉菜单自动变到相应的数据，同时选中gridview中相对应的行，不知道如何实现，很急，求大神相助"



其实，实现起来算得上简单，下面先从准备数据开始，创建一个对象Customer:

source code:

using System;using System.Collections.Generic;using System.Linq;using System.Web;/// 
/// Summary description for Customer/// 
namespace Insus.NET{    public class Customer    {        private int _CustomerID;        private string _CustomerName;        private string _PID;        private bool _IsActived;        public int CustomerID        {            get { return _CustomerID; }            set { _CustomerID = value; }        }        public string CustomerName        {            get { return _CustomerName; }            set { _CustomerName = value; }        }        public string PID        {            get { return _PID; }            set { _PID = value; }        }        public bool IsActived        {            get { return _IsActived; }            set { _IsActived = value; }        }    }}

View Code

接下来，我们创建一个实具，数据来源全在此类实现 CustomerEntity:

source code:

using System;using System.Collections.Generic;using System.Linq;using System.Web;/// 
/// Summary description for CustomerEntity/// 
namespace Insus.NET{    public class CustomerEntity    {        public CustomerEntity()        {            //            // TODO: Add constructor logic here            //        }        public IEnumerable Customers = new List {            new Customer {CustomerID = 9,CustomerName = "张三",PID = "123456789012"  },            new Customer {CustomerID = 10,CustomerName = "李四",PID = "321245677812"  },            new Customer {CustomerID = 30,CustomerName = "吴广",PID = "213445678912"  },            new Customer {CustomerID = 35,CustomerName = "王维",PID = "334456789012"  },            new Customer {CustomerID = 36,CustomerName = "赵勇",PID = "213445678912"  }        };        public IEnumerable GetForFirstDropDownData()        {            var oo = Customers.Select(o => new Customer { CustomerID = o.CustomerID, CustomerName = o.CustomerName });            return oo;        }        public IEnumerable GetForSecondDropDownData(int customerId)        {            var oo = Customers.Select(o => new Customer { CustomerID = o.CustomerID, PID = o.PID })                                .Where(w => w.CustomerID == customerId);            return oo;        }        public IEnumerable GetForGridview(int customerId)        {            List _cust = new List();            foreach (Customer c in Customers)            {                if (c.CustomerID == customerId)                    _cust.Add(new Customer { CustomerID = c.CustomerID, CustomerName = c.CustomerName, PID = c.PID, IsActived = true });                else                    _cust.Add(c);            }            return _cust;        }    }}

View Code

Ok,数据准备好了，下面就可以创建网页实现相关的功能xxx.aspx:

source code:

html>        

View Code

xxx.aspx.cs:

source code:

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using Insus.NET;using System.Data;public partial class _Default : System.Web.UI.Page{    CustomerEntity ce = new CustomerEntity();    protected void Page_Load(object sender, EventArgs e)    {        if (!IsPostBack)        {            Data_Binding();        }    }    private void Data_Binding()    {        this.DropDownList1.DataSource = ce.GetForFirstDropDownData();        this.DropDownList1.DataValueField = "CustomerID";        this.DropDownList1.DataTextField = "CustomerName";        this.DropDownList1.DataBind();        this.DropDownList2.DataSource = ce.GetForSecondDropDownData(Convert.ToInt32(this.DropDownList1.SelectedItem.Value));        this.DropDownList2.DataTextField = "PID";        this.DropDownList2.DataBind();        this.GridView1.DataSource = ce.GetForGridview(Convert.ToInt32(this.DropDownList1.SelectedItem.Value));        this.GridView1.DataBind();    }    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)    {        var ddl = (DropDownList)sender;        this.DropDownList2.DataSource = ce.GetForSecondDropDownData(Convert.ToInt32(ddl.SelectedItem.Value));        this.DropDownList2.DataTextField = "PID";        this.DropDownList2.DataBind();        this.GridView1.DataSource = ce.GetForGridview(Convert.ToInt32(ddl.SelectedItem.Value));        this.GridView1.DataBind();    }    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)    {        if (e.Row.RowType != DataControlRowType.DataRow) return;        Customer drv = (Customer)e.Row.DataItem;        bool isActived = (bool)drv.IsActived;        if (isActived)            e.Row.BackColor = System.Drawing.Color.Red;    }}

View Code

动画实时演示：