DropDownList与ListBox关联及ListBox添加删除

前台代码：

(另外还有几个Hidden控件)

<table><tr align="left"><td align="right">管理员部门：</td><td>
                     <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
                     </asp:DropDownList></td></tr>
                <tr><td colspan="2">
                    <table width="100%">
                        <tr>
                            <td>
                                <asp:ListBox ID="ListBox1" runat="server" Height="100" Width="100"></asp:ListBox></td>
                            <td style=" 5px" valign="middle">
                                <table >   <tr>
                        <td>
                            <a href="javascript:toright()"><img src="../Images/btn_toright.gif" style="border:0px;" /></a>
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <a href="javascript:toleft()"><img src="../Images/btn_toleft.gif" style="border:0px;" /></a>
                        </td>
                    </tr></table>
                            </td>
                            <td>
                                <asp:ListBox ID="ListBox2" runat="server" Height="100" Width="100"></asp:ListBox></td>
                        </tr>
                    </table>

Javascript:

function toright()
{
    var textstr="";
    var valuestr="";
    var thisid=0;
    var i=0;
    var len=document.getElementById('<%= ListBox1.ClientID %>').options.length;
    var len2=document.getElementById('<%= ListBox2.ClientID %>').options.length;
    i = document.getElementById('<%= ListBox1.ClientID %>').selectedIndex;
    if(i>-1)
    {
        textstr=document.getElementById('<%= ListBox1.ClientID %>').options[i].text;
        valuestr=document.getElementById('<%= ListBox1.ClientID %>').options[i].value;
        thisid=i;
        document.getElementById('<%= ListBox2.ClientID %>').options[len2] = new Option(textstr,valuestr,true,true);
        document.getElementById('<%= ListBox1.ClientID %>').options[i].parentNode.removeChild(document.getElementById('<%= ListBox1.ClientID %>').options[i]);
        if(document.getElementById('<%= ListBox1.ClientID %>').options.length>0)
        {
            document.getElementById('<%= ListBox1.ClientID %>').selectedIndex = 0;
        }
        if(document.getElementById('<%= Hidden1.ClientID %>').value=="")
            document.getElementById('<%= Hidden1.ClientID %>').value=valuestr;
        else
            document.getElementById('<%= Hidden1.ClientID %>').value+="|"+valuestr;
    }
}
function toleft()
{    
    var textstr="";
    var valuestr="";
    var thisid=0;
    var i=0;
    var len=document.getElementById('<%= ListBox2.ClientID %>').options.length;
    var len2=document.getElementById('<%= ListBox1.ClientID %>').options.length;
    document.getElementById('<%= Hidden1.ClientID %>').value="";
    i = document.getElementById('<%= ListBox2.ClientID %>').selectedIndex;
    if(i>-1)
    {
        textstr=document.getElementById('<%= ListBox2.ClientID %>').options[i].text;
        valuestr=document.getElementById('<%= ListBox2.ClientID %>').options[i].value;
        thisid=i;
        document.getElementById('<%= ListBox1.ClientID %>').options[len2] = new Option(textstr,valuestr,true,true);
        document.getElementById('<%= ListBox2.ClientID %>').options[i].parentNode.removeChild(document.getElementById('<%= ListBox2.ClientID %>').options[i]);
        if(document.getElementById('<%= ListBox2.ClientID %>').options.length>0)
        {
            document.getElementById('<%= ListBox2.ClientID %>').selectedIndex=0;
        }
    }
    for(i=0;i<document.getElementById('<%= ListBox2.ClientID %>').options.length;i++)
    {
        if(document.getElementById('<%= Hidden1.ClientID %>').value=="")
            document.getElementById('<%= Hidden1.ClientID %>').value=document.getElementById('<%= ListBox2.ClientID %>').options[i].value;
        else
            document.getElementById('<%= Hidden1.ClientID %>').value+="|"+document.getElementById('<%= ListBox2.ClientID %>').options[i].value;
    }
}

后台代码：

protected void initlist(string DepartmentCode,string mli)
        {
            string[] arr = mli.Split('|');
            ListItem li = null;
            ListBox1.Items.Clear();
            ListBox2.Items.Clear();
            string id = "";
            string name = "";
            if (DepartmentCode != "")
                ds = userbll.GetList("UnitCode='" + Hidden7.Value + "' and DepartmentCode='" + DepartmentCode + "'");
            else
                ds = userbll.GetList("UnitCode='" + Hidden7.Value + "'");
            Hidden1.Value = "";
            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            {
                id = ds.Tables[0].Rows[i]["ID"].ToString();
                name = ds.Tables[0].Rows[i]["CName"].ToString();
                if (arr.Length > 0)
                {
                    for (int j = 0; j < arr.Length; j++)
                    {
                        li = new ListItem(name, id);
                        if (id == arr[j])
                        {
                            ListBox2.Items.Add(li);
                            if (Hidden1.Value == "")
                                Hidden1.Value += id;
                            else
                                Hidden1.Value += "|" + id;
                        }
                        else
                        {
                            ListBox1.Items.Add(li);
                        }
                    }
                }
                else
                {
                    li = new ListItem(name, id);
                    ListBox1.Items.Add(li);
                }
                
            }
        }

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            ListItem li = null;
            ListBox1.Items.Clear();
            string id = "";
            string name = "";
            if (DropDownList1.SelectedValue != "0")
            {
                ds = userbll.GetList("UnitCode='" + Hidden7.Value + "' and DepartmentCode='" + DropDownList1.SelectedValue + "'");
            }
            else
            {
                ds = userbll.GetList("UnitCode='" + Hidden7.Value + "' and DepartmentCode is null");
            }
            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            {
                id = ds.Tables[0].Rows[i]["ID"].ToString();
                name = ds.Tables[0].Rows[i]["CName"].ToString();
                li = new ListItem(name, id);
                ListBox1.Items.Add(li);
            }
        }