两个下拉框数据互连问题。。。

Question

当我点大类的时候，如果这个大类里有小类的话，小类下拉框激活。在不类框中显示大类的小类列表，如果没有小类不激活。
代码如下。数据库都写好了，就是不知道怎么让这两个下拉框互联起来。。protected void Page_Load(object sender, EventArgs e)
    {
        OleDbConnection connstr = DBConnections.DBConnections.createConnection();
        connstr.Open();        OleDbCommand cmd = new OleDbCommand();
        cmd.Connection = connstr;
        cmd.CommandText = "SELECT [BigID], [BigClassName] FROM [Hover_BigClass_New]";        DataSet daset = new DataSet();
        OleDbDataAdapter ol = new OleDbDataAdapter();
        ol.SelectCommand = cmd;
        ol.Fill(daset);        if (daset.Tables.Count > 0)
        {
            if (daset.Tables[0].Rows.Count > 0)
            {
                ClassNews.Enabled = true;
                ClassNews.AutoPostBack = true;
                ClassNews.DataSource = daset;
                ClassNews.DataTextField = "BigClassName";
                ClassNews.DataValueField = "BigID";
                ClassNews.DataBind();
                if(Request["BigClassName"].ToString()!=null)
                {
                    ////////////小类
                    String BigClassNames = Request["BigClassName"].ToString();
                    OleDbCommand cmd1 = new OleDbCommand();
                    cmd1.Connection = connstr;
                    cmd1.CommandText = "Select * From Hover_SmallClass_New where BigClassName='" + BigClassNames + "'";                    DataSet ds1 = new DataSet();
                    OleDbDataAdapter dsda = new OleDbDataAdapter();
                    dsda.SelectCommand = cmd1;
                    dsda.Fill(ds1);                    if (ds1.Tables.Count > 0)
                    {
                        if (ds1.Tables[0].Rows.Count > 0)
                        {
                            SmallClassNews.DataSource = ds1;
                            SmallClassNews.Enabled = true;
                            SmallClassNews.DataTextField = "SmallClassName";
                            SmallClassNews.DataValueField = "SmallClassID";
                            SmallClassNews.DataBind();
                        }
                        else
                        {
                            SmallClassNews.Enabled = false;
                        }
                    }
                    else
                    {
                        SmallClassNews.Enabled = false;
                    }
                    ds1.Dispose();
                    ds1 = null;
　　　　　　　　　　///////////小类结束
                }
                
            }
            else
            {
                ClassNews.Enabled = false;
            }
        }
        else
        {
            ClassNews.Enabled = false;
        }        ol.Dispose();
        ol = null;        connstr.Close();    }
以下是前台代码
        <asp:DropDownList ID="ClassNews" runat="server" Height="23px" Width="86px">
        </asp:DropDownList>
 
        　<asp:DropDownList ID="SmallClassNews" runat="server" Height="23px" Width="86px">
        </asp:DropDownList>

Answer 1

可以在ClassNews控制里,在其SelectIndexChaned事件下编写实现控件联动操作的代码!
for sample:
protected void ClassNews_SelectedIndexChanged(object sender ,EventArgs e)
{
//小类code(引用你自己写的)
              String BigClassNames = Request["BigClassName"].ToString(); 
                    OleDbCommand cmd1 = new OleDbCommand(); 
                    cmd1.Connection = connstr; 
                    cmd1.CommandText = "Select * From Hover_SmallClass_New where BigClassName='" + BigClassNames + "'";                     DataSet ds1 = new DataSet(); 
                    OleDbDataAdapter dsda = new OleDbDataAdapter(); 
                    dsda.SelectCommand = cmd1; 
                    dsda.Fill(ds1);                     if (ds1.Tables.Count > 0) 
                    { 
                        if (ds1.Tables[0].Rows.Count > 0) 
                        { 
                            SmallClassNews.DataSource = ds1; 
                            SmallClassNews.Enabled = true; 
                            SmallClassNews.DataTextField = "SmallClassName"; 
                            SmallClassNews.DataValueField = "SmallClassID"; 
                            SmallClassNews.DataBind(); 
                        } 
                        else 
                        { 
                            SmallClassNews.Enabled = false; 
                        } 
                    } 
                    else 
                    { 
                        SmallClassNews.Enabled = false; 
                    } 
                    ds1.Dispose(); 
                    ds1 = null; 
}

Answer 2

拖一个updatepanel然后用dropdownlist中的selectedchanged事件。

Answer 3

如以下示例：protected void Page_Load(object sender, EventArgs e)
    {
        connstr = System.Configuration.ConfigurationSettings.AppSettings["sql2005"];
        if (!IsPostBack)
        {
            SelectedVisible("allFalse");
        }
    }    /// <summary>
    /// 选择控件可见与否
    /// </summary>
    /// <param name="temp">传递的参数控制显示什么</param>
    private void SelectedVisible(string temp)
    {
        if (temp.Equals("allFalse"))
        {
            lblname.Visible = false;
            ddlRname.Visible = false;
        }
        else if (temp.Equals("RnameVisible"))
        {
            lblname.Visible = true;
            ddlRname.Visible = true;
        }
    }
protected void ddlRname_SelectedIndexChanged(object sender, EventArgs e)
    {
        pt = new string[16];
        for (int i = 0; i < 16; i++)
        {
            pt[i] = "&nbsp;";
        }
        if (ddlRtype.SelectedValue.ToString().Equals("1"))
        {
            //绑定小类1
        }
        else if (ddlRtype.SelectedValue.ToString().Equals("2"))
        {
            //绑定小类2
        }
        else if (ddlRtype.SelectedValue.ToString().Equals("3"))
        {
            //绑定小类3
        }
        else
        {
            //绑定小类4
        }
    }    protected void ddlRtype_SelectedIndexChanged(object sender, EventArgs e)
    {
        SelectedVisible("allFalse");
        ddlRname.Items.Clear();
        ddlRname.Items.Add(new ListItem("---请选择---", "-1"));
        if (ddlRtype.SelectedValue.ToString().Equals("1"))
        {
            (new SqlDataAccess(connstr)).ConnectDDL("SELECT sid, id, name, type FROM ZCityIdToName ORDER BY id", "ZCityIdToName", "name", "id", ddlRname);
            SelectedVisible("RnameVisible");
        }
        else if (ddlRtype.SelectedValue.ToString().Equals("2"))
        {
            (new SqlDataAccess(connstr)).ConnectDDL("SELECT sid, id, name, type FROM ZCityIdToName ORDER BY id", "ZCityIdToName", "name", "id", ddlRname);
            SelectedVisible("RnameVisible");
        }
        else if (ddlRtype.SelectedValue.ToString().Equals("3"))
        {
            (new SqlDataAccess(connstr)).ConnectDDL("SELECT sid, id, name, type FROM ZCityIdToName ORDER BY id", "ZCityIdToName", "name", "id", ddlRname);
            SelectedVisible("RnameVisible");
        }
        else
        {
            SelectedVisible("allFalse");
        }
    }

Answer 4

以下是前台代码 
        <asp:DropDownList ID="ClassNews" runat="server" Height="23px" Width="86px"> 
        </asp:DropDownList>         　 <asp:DropDownList ID="SmallClassNews" runat="server" Height="23px" Width="86px"> 
        </asp:DropDownList> 
==============================
SmallClassNews要根据ClassNews选中显示
那么第一次在pageload 先绑定 ClassNews
然后在ClassNews的selectchanged 事件里面根据 ClassNews选中的项再读取数据出来 再绑定到SmallClassNews ，之前 先把ClassNews 的autopostback属性设置为true

Answer 5

 发现一个问题，如果用SelectIndexChaned事件，它整个页面就会刷新一次，我里边有一个ＨＴＭＬ编辑器，刷新起来很不顺，
有什么解决方法没有．．．

Answer 6

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.OleDb;public partial class admins_addnew : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            showBigData();
            showData();
        }
    }    protected void Button1_Click(object sender, EventArgs e)
    {
        this.Label1.Text = this.HtmlEditor1.Text;
        
    }    public void showBigData()
    {
        OleDbConnection connstr = DBConnections.DBConnections.createConnection();
        connstr.Open();        OleDbCommand cmd = new OleDbCommand();
        cmd.Connection = connstr;
        cmd.CommandText = "SELECT BigID, BigClassName FROM Hover_BigClass_New";        DataSet daset = new DataSet();
        OleDbDataAdapter ol = new OleDbDataAdapter();
        ol.SelectCommand = cmd;
        ol.Fill(daset);        if (daset.Tables.Count > 0)
        {
            if (daset.Tables[0].Rows.Count > 0)
            {
                ClassNews.Enabled = true;
                ClassNews.AutoPostBack = true;
                ClassNews.DataSource = daset;
                ClassNews.DataTextField = "BigClassName";
                ClassNews.DataValueField = "BigID";
                ClassNews.DataBind();
                if (Request.QueryString["BigClassName"] != null)
                    if (ClassNews.Items.FindByValue(Request.QueryString["BigClassName"].ToString()) != null)
                        ClassNews.Items.FindByValue(Request.QueryString["BigClassName"].ToString()).Selected = true;            }
            else
            {
                ClassNews.Enabled = false;
            }
        }
        else
        {
            ClassNews.Enabled = false;
        }        ol.Dispose();
        ol = null;        connstr.Close();
    }
    public void showData()
    {
        //小类code(引用你自己写的) 
        OleDbConnection connstr = DBConnections.DBConnections.createConnection();
        connstr.Open();        String BigClassNames = Convert.ToString(ClassNews.SelectedItem.Value);
        OleDbCommand cmd1 = new OleDbCommand();
        cmd1.Connection = connstr;
        cmd1.CommandText = "Select SmallClassID,SmallClassName,BigClassName From Hover_SmallClass_New where BigClassName='" + BigClassNames + "'";        DataSet ds1 = new DataSet();
        OleDbDataAdapter dsda = new OleDbDataAdapter();
        dsda.SelectCommand = cmd1;
        dsda.Fill(ds1);        if (ds1.Tables.Count > 0)
        {
            if (ds1.Tables[0].Rows.Count > 0)
            {
                SmallClassNews.DataSource = ds1;
                ClassNews.AutoPostBack = true;
                SmallClassNews.Enabled = true;
                SmallClassNews.DataTextField = "SmallClassName";
                SmallClassNews.DataValueField = "SmallClassID";
                SmallClassNews.DataBind();
                if (Request.QueryString["BigClassName"] != null)
                    if (SmallClassNews.Items.FindByValue(Request.QueryString["BigClassName"].ToString()) != null)
                        SmallClassNews.Items.FindByValue(Request.QueryString["BigClassName"].ToString()).Selected = true;
            }
            else
            {
                SmallClassNews.Enabled = false;
            }
        }
        else
        {
            SmallClassNews.Enabled = false;
        }
        ds1.Dispose();
        ds1 = null;
    }    protected void SmallClassNews_SelectedIndexChanged(object sender, EventArgs e)
    {
        showData();
    }    protected void ClassNews_SelectedIndexChanged(object sender, EventArgs e)
    {
        showBigData();
    }
}为什么在前台页面点大类,刷新后没有跳到相应的大类上,还是出现列表第一条数据.小类也没有数据???????????????

Answer 7

回答过了啊。。想要联动，最好使用AJAX来做。。在.net中最简单的办法就是用updatePanel..什么都不用干。。效果一样。。

Answer 8

想不刷新使用ajaxpro框架也可以

Answer 9

很明显给楼主介绍使用Ajax是没用的，呵呵。这样：vs 2003 -- >
        <asp:DropDownList ID="ClassNews" runat="server" Height="23px" Width="86px" AutoPostBack="True" SelectedIndexChanged = "ClassNews_SelectedIndexChanged"> 
        </asp:DropDownList> vs 2005<asp:DropDownList ID="ClassNews" runat="server" Height="23px" Width="86px" AutoPostBack="True"  OnSelectedIndexChanged="ClassNews_SelectedIndexChanged"> 
        </asp:DropDownList>         　 <asp:DropDownList ID="SmallClassNews" runat="server" Height="23px" Width="86px"> 
        </asp:DropDownList> private void bindtopDL()
{
    OleDbConnection connstr = DBConnections.DBConnections.createConnection(); 
    connstr.Open();     OleDbCommand cmd = new OleDbCommand(); 
    cmd.Connection = connstr; 
    cmd.CommandText = "SELECT [BigID], [BigClassName] FROM [Hover_BigClass_New]"; 
    DataSet daset = new DataSet(); 
    OleDbDataAdapter ol = new OleDbDataAdapter(); 
    ol.SelectCommand = cmd; 
    ol.Fill(daset);     if (daset.Tables[0].Rows.Count > 0) 
    { 
        ClassNews.AutoPostBack = true;
        ClassNews.DataSource = daset; 
        ClassNews.DataTextField = "BigClassName"; 
        ClassNews.DataValueField = "BigID"; 
        ClassNews.DataBind(); 
    }
    else
    {
        ClassNews.AutoPostBack = false;
    }
}private void bindsubDL()
{
    if (this.BigClassName.SelectedItem.value != "")
    { 
       OleDbCommand cmd1 = new OleDbCommand(); 
       cmd1.Connection = connstr; 
       cmd1.CommandText = "Select * From Hover_SmallClass_New where BigClassName='" +this.BigClassName.SelectedItem.value+ "'";        DataSet ds1 = new DataSet(); 
       OleDbDataAdapter dsda = new OleDbDataAdapter(); 
       dsda.SelectCommand = cmd1; 
       dsda.Fill(ds1);        if (ds1.Tables[0].Rows.Count > 0) 
       { 
           SmallClassNews.Enabled = true; 
           SmallClassNews.DataSource = ds1; 
           SmallClassNews.DataTextField = "SmallClassName"; 
           SmallClassNews.DataValueField = "SmallClassID"; 
           SmallClassNews.DataBind(); 
       }
       else
       {
           SmallClassNews.Enabled = false; 
       }
}
protected void Page_Load(object sender, EventArgs e) 
{
     this.bindtopDL();
     this.bindsubDL();
}
protected void ClassNews_SelectedIndexChanged(object sender,System.EventArgs e)
{
     this.bindsubDL();
}

Answer 10

最讨厌动不动就搬ajax出来的人！
一点技术含量都没有！

Answer 11

建议楼住使用iframe把下拉放在一个单独的页面中
用到的时候
var ddl1_va = window.frames[0].document.getElementById("ddl1");
将ddl1_va赋给一个hidden控件即可

Answer 12

march22 和lfywy 的思路还可以,不过还是要刷新的.updatePanel没有用过.不知道怎么用?晚上查一下资料.....

Answer 13

用微軟的updatepanel 做聯動不是很好 dropdown選擇的時候 頁面或有閃爍，雖然不刷最好是自己寫ajax 比如使用ajax.dll 或是jquery

Answer 14

呵呵 已经这么多人回答了 用updatePanel没错了   双手同意.....updatePanel

Answer 15

我用updatePanel解决了刷新问题,只要是回答的根我的问题有关系,根据实际情况都会给分,谢谢你们,不过还有一个问题,
当我选大类列表其他项的时候,并没有停在选中的那一项,而是又回到了大类列表的第一项数据那,比如,大类有,AA,BB,CC
我点了BB,但是列表没有停在BB上,而是又回到了AA.....怎么解决这个问题...
代码如下:
 protected void Page_Load(object sender, EventArgs e)
    {
        this.bindtopDL();
        this.bindsubDL();
       
    } 
    private void bindtopDL() 
    { 
        OleDbConnection connstr = DBConnections.DBConnections.createConnection(); 
        connstr.Open();         OleDbCommand cmd = new OleDbCommand(); 
        cmd.Connection = connstr;
        cmd.CommandText = "SELECT * FROM [Hover_BigClass_New]"; 
        DataSet daset = new DataSet(); 
        OleDbDataAdapter ol = new OleDbDataAdapter(); 
        ol.SelectCommand = cmd; 
        ol.Fill(daset);         if (daset.Tables[0].Rows.Count > 0) 
        { 
            ClassNews.AutoPostBack = true; 
            ClassNews.DataSource = daset; 
            ClassNews.DataTextField = "BigClassName";
            ClassNews.DataValueField = "BigClassID"; 
            ClassNews.DataBind();
 
        } 
        else 
        { 
            ClassNews.AutoPostBack = false; 
        }
        ol.Dispose();
        ol = null;
        connstr.Close();
    }    private void bindsubDL()
    {
        if (this.ClassNews.SelectedItem.ToString() != "")
        {
            OleDbConnection connstr = DBConnections.DBConnections.createConnection();
            connstr.Open();             OleDbCommand cmd1 = new OleDbCommand();
            cmd1.Connection = connstr;
            cmd1.CommandText = "Select * From Hover_SmallClass_New where BigClassName='" + ClassNews.SelectedItem.ToString() + "'";            DataSet ds1 = new DataSet();
            OleDbDataAdapter dsda = new OleDbDataAdapter();
            dsda.SelectCommand = cmd1;
            dsda.Fill(ds1);            if (ds1.Tables[0].Rows.Count > 0)
            {
                SmallClassNews.Enabled = true;
                SmallClassNews.DataSource = ds1;
                SmallClassNews.DataTextField = "SmallClassName";
                SmallClassNews.DataValueField = "SmallClassID";
                SmallClassNews.DataBind();
           
            }
            else
            {
                SmallClassNews.Enabled = false;
            }
            ds1.Dispose();
            ds1 = null;
            connstr.Close();
        }
    }    protected void ClassNews_SelectedIndexChanged(object sender,System.EventArgs e) 
    { 
        this.bindsubDL(); 
    }

Answer 16

if (dataSet.Tables[0].Rows.Count > 0)
                {
                    DropDownList3.Enabled = true;
                    ImageButton1.Enabled = true;
                    Label1.Text = "";
                    DropDownList3.DataSource = dataSet;
                    DropDownList3.DataTextField = "textfield";
                    DropDownList3.DataValueField = "id";
                    DropDownList3.DataBind();
                    if(Request.QueryString["chubanshe"]!=null)
                        if (DropDownList3.Items.FindByValue(Request.QueryString["chubanshe"].ToString()) != null)
                            DropDownList3.Items.FindByValue(Request.QueryString["chubanshe"].ToString()).Selected = true;                }//如果含有记录就说明有新的数据
                else
                {
                    Label1.Text = "当前年级的所选学科暂时没有内容,<a href='addleibie.aspx'>去添加学科内容>></a>";
                    DropDownList3.Enabled = false;
                    ImageButton1.Enabled = false;
                }
这是别人的代码,但是那几句我并没有看懂,希望能找到一个解决的方法

Answer 17

先写2个事件
drop1_selectedChaning() 大类的
drop2_....()小类的
第1个大类的直接绑定数据库
第2个小类的把drop1.selecedValue值传到第2个小类的数据库源上
在大类的changing事件里调用小类的changing 就可以了就会显示在你选大类时小类自动绑定了.

Answer 18

问题解决,附上代码,前台
<form id="form1" runat="server">
    <div>
    
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
          <Triggers>
        <asp:AsyncPostBackTrigger ControlID="ClassNews" EventName="SelectedIndexChanged" />
        </Triggers>
        <ContentTemplate>
                   <fieldset>
                     <legend></legend>
      
        
        
        新闻标题<asp:TextBox ID="title" runat="server"></asp:TextBox>
        <br />
        <br />
        新闻类别　　
        
       
        <asp:DropDownList ID="ClassNews" runat="server" Height="23px" Width="86px" 
            AutoPostBack="True" OnSelectedIndexChanged="ClassNews_SelectedIndexChanged">
        </asp:DropDownList>
 
        　<asp:DropDownList ID="SmallClassNews" runat="server" Height="23px" Width="86px">
        </asp:DropDownList>
        &nbsp;&nbsp; 
        <br />        <br />
        
        <br />
        <asp:Label ID="Label2" runat="server" Text="Label"></asp:Label>
        <br />
        <br />
        <asp:Label ID="Label3" runat="server" Text="Label"></asp:Label>
             </fieldset>
            </ContentTemplate>
        </asp:UpdatePanel>
         新闻内容
         <cc1:HtmlEditor ID="HtmlEditor1" runat="server"  TF_EditHtml="1" TF_UpTu="1" ResourcesPath="HtmlEditor"  />        <br />
        <br />
       
        <br />
        <br />
        发布人<asp:TextBox ID="person" runat="server"></asp:TextBox>
        <br />
        <br />
        摘录网址<asp:TextBox ID="zWeb" runat="server"></asp:TextBox>
        <br />
        <br />
        录入时间<asp:TextBox ID="time" runat="server"></asp:TextBox>
        <br />
        <br />
        <br />
        <asp:Button ID="Button1" runat="server" Text="提交" onclick="Button1_Click" />
    
        <br />
        <br />
        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
        
        
        
    
        
    
    </div>
    </form>
后台代码
public partial class admins_addnew : System.Web.UI.Page
{
    
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
       
        this.bindtopDL();
        this.bindsubDL();
        }
    } 
    private void bindtopDL() 
    { 
        OleDbConnection connstr = DBConnections.DBConnections.createConnection(); 
        connstr.Open();         OleDbCommand cmd = new OleDbCommand(); 
        cmd.Connection = connstr;
        cmd.CommandText = "SELECT * FROM [Hover_BigClass_New]"; 
        DataSet daset = new DataSet(); 
        OleDbDataAdapter ol = new OleDbDataAdapter(); 
        ol.SelectCommand = cmd; 
        ol.Fill(daset);         if (daset.Tables[0].Rows.Count > 0) 
        { 
            ClassNews.AutoPostBack = true; 
            ClassNews.DataSource = daset; 
            ClassNews.DataTextField = "BigClassName";
            ClassNews.DataValueField = "BigClassID"; 
            ClassNews.DataBind();
 
        } 
        else 
        { 
            ClassNews.AutoPostBack = false; 
        }
        ol.Dispose();
        ol = null;
        connstr.Close();
    }    private void bindsubDL()
    {
        if (this.ClassNews.SelectedItem.ToString() != "")
        {
            OleDbConnection connstr = DBConnections.DBConnections.createConnection();
            connstr.Open();            OleDbCommand cmd1 = new OleDbCommand();
            cmd1.Connection = connstr;
            cmd1.CommandText = "Select * From Hover_SmallClass_New where BigClassName='" + ClassNews.SelectedItem.ToString() + "'";            DataSet ds1 = new DataSet();
            OleDbDataAdapter dsda = new OleDbDataAdapter();
            dsda.SelectCommand = cmd1;
            dsda.Fill(ds1);            if (ds1.Tables[0].Rows.Count > 0)
            {
                
                SmallClassNews.Enabled = true;
                SmallClassNews.DataSource = ds1;
                SmallClassNews.DataTextField = "SmallClassName";
                SmallClassNews.DataValueField = "SmallClassID";
                SmallClassNews.DataBind();            }
            else
            {
                SmallClassNews.Enabled = false;
                
            }
            ds1.Dispose();
            ds1 = null;
            connstr.Close();
        }
        else
        {
            
            SmallClassNews.Enabled = false;
        }
    }    protected void ClassNews_SelectedIndexChanged(object sender,System.EventArgs e) 
    { 
        this.bindsubDL(); 
    }

Answer 19

也可以用JS来秦无刷新二级联动呀，用ASP.NET的回调接口，效果还不错，正在使用中，跟AJAX思想一样