可以多选的下拉列表框

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可以多选的下拉列表框

自己做开发的过程中，经常有时候遇到一次要选择多个值的情况。而用DropDownList一次只能选择一个，没办法自己最近抽空写了一个方便自己一户用，不过很简单，拿出来跟大家交流一下。

界面如下：

简单介绍一下：

这是一个用户控件，其中包含了一个文本框用来显示选中Text值，一个隐藏控件用来保存Value值，一个button控件用来调出选择面板，一根Gridview 用来绑定待选择的值，还有4个操作按钮，全选取消确定关闭。

代码如下：

1、 MoreSelectBoxl.ascx

     <%@ Control Language="C#" AutoEventWireup="true" CodeFile="MoreSelectBoxl.ascx.cs" Inherits="UseControl_MoreSelectBoxl" %>
<script language="javascript" type="text/javascript">
    function Onload()
    {
        var obj = document.getElementById("SelectListBox");

        obj.style.display="block";
        obj.style.border="1px #666666 solid";
        obj.style.backgroundColor="#CCCCCC";
    }
</script>

<div style="width: 200px; height: 20px;">
    <asp:TextBox ID="txtText" runat="server" Width="160"></asp:TextBox>
    <asp:HiddenField ID="txtValue" runat="server" />
    <asp:Button ID="btnSelect" Text=">>" runat="server" OnClick="btnSelect_Click" />
</div>
<div id="SelectListBox"   style="width: 200px; height: 285px; position: absolute; z-index: 3000; border:1px #666666 solid; background-color:#CCCCCC; <%=IsDisplay %>">
    <div style="width: 200px; margin: auto; height: 270px; ">
        <asp:GridView ID="gvList" Width="200" runat="server"
            AutoGenerateColumns="false" AllowPaging="true" PageSize="10"
            onpageindexchanging="gvList_PageIndexChanging">
            <FooterStyle BackColor="#C6C3C6" ForeColor="Black" />
            <RowStyle BackColor="#ECF5FF" ForeColor="Black" />
            <SelectedRowStyle BackColor="#9471DE" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#A6CBEF" ForeColor="Black" HorizontalAlign="Right" />
            <HeaderStyle BackColor="#A6CBEF" Font-Bold="True" ForeColor="#404040" BorderColor="#000000" />

2、MoreSelectBoxl.ascx.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
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.Web.Caching;

public partial class UseControl_MoreSelectBoxl : System.Web.UI.UserControl
{
#region 属性

    private Object _DataSource;
    private string _ItemText;
    private string _ItemHeaderText;
    private string _ItemValue;
    public Object DataSource
    {
        get { return this._DataSource; }
        set { this._DataSource = value; }
    }

    public string ItemText
    {
        get { return this._ItemText; }
        set { this._ItemText = value; }
    }
    public string ItemHeaderText
    {
        get { return this._ItemHeaderText; }
        set { this._ItemHeaderText = value; }
    }
    public string ItemValue
    {
        get { return this._ItemValue; }
        set { this._ItemValue = value; }
    }
    #endregion

public string IsDisplay;

public event EventHandler SelectButton;//事件句柄

    protected void Page_Load(object sender, EventArgs e)
    {
        IsDisplay = "Display:none";
        if (!IsPostBack)
        {
            this.txtText.Text = "";
        }
    }

    public void BindDataSource()
    {
        gvList.ShowHeader = false;
        gvList.DataSource = this.DataSource;
        gvList.DataBind();
    }

    #region 事件
    protected void btnSelect_Click(object sender, EventArgs e)
    {

        if (SelectButton != null)
        {
            SelectButton(this, new EventArgs());
        }
        IsDisplay = "Display:block";

BindDataSource();

    }
    protected void btnClose_Click(object sender, EventArgs e)
    {
        IsDisplay = "Display:none";
        gvList.DataSource = null;
        gvList.DataBind();
        this.txtText.Text = "";
    }

    protected void gvList_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        if (SelectButton != null)
        {
            SelectButton(this, new EventArgs());
        }
        IsDisplay = "Display:block";
        gvList.PageIndex = e.NewPageIndex;
        BindDataSource();
    }

    protected void BtnOk_Click(object sender, EventArgs e)
    {
        IsDisplay = "Display:block";
        string _IText = string.Empty;
        string _IValue = string.Empty;

        foreach (GridViewRow Rows in gvList.Rows)
        {
            if (((CheckBox)Rows.Cells[0].FindControl("CheckID")).Checked == true)
            {
                if (string.IsNullOrEmpty(_IText))
                {
                    _IText +=((Label)Rows.Cells[1].FindControl("ItemText")).Text.ToString().Trim().Replace(","," ");
                    _IValue += ((Label)Rows.Cells[2].FindControl("ItemValue")).Text.ToString().Trim().Replace(",", " ");
                }
                else
                {
                    _IText += "," + ((Label)Rows.Cells[1].FindControl("ItemText")).Text.ToString().Replace(",", " ");
                    _IValue += "," + ((Label)Rows.Cells[2].FindControl("ItemValue")).Text.ToString().Replace(",", " ");
                }
            }
        }

        //这里要做检测，内容是否存在。
        if (string.IsNullOrEmpty(this.txtText.Text.Trim()))
        {
            this.txtText.Text = _IText;
            this.txtValue.Value = _IValue;
        }
        else
        {
            this.txtText.Text +=","+_IText;
            this.txtValue.Value +=","+_IValue;
        }

        IsDisplay = "Display:none";
        gvList.DataSource = null;
        gvList.DataBind();

}

    protected void BtnAll_Click(object sender, EventArgs e)
    {
        IsDisplay = "Display:block";
        foreach (GridViewRow Rows in gvList.Rows)
        {
            ((CheckBox)Rows.Cells[0].FindControl("CheckID")).Checked = true;
        }
    }
    protected void BtnCancel_Click(object sender, EventArgs e)
    {
        IsDisplay = "Display:block";
        foreach (GridViewRow Rows in gvList.Rows)
        {
            ((CheckBox)Rows.Cells[0].FindControl("CheckID")).Checked = false;
        }
    }
    #endregion

}