ASP.NET Web 控件加载与数据绑定-优快云博客

本文链接：https://blog.youkuaiyun.com/start55/article/details/5549376

本文介绍了一个 ASP.NET Web 用户控件的实现方式，重点在于页面加载时控件的状态初始化及通过数据库查询填充下拉列表的过程。具体包括如何在页面首次加载时避免 PostBack、使用 SqlHelper 执行 SQL 查询并填充 DropDownList 的选项。

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using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using DAL;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Text;

public partial class addList : System.Web.UI.UserControl
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
            init();
    }
    public string stateName
    {
        get
        {
            if (stateList.SelectedIndex <= 0)
            {
                return null;
            }
            else
            {
                return stateList.SelectedItem.Text;
            }
        }
    }
    public string stateId
    {
        get
        {
            if (stateList.SelectedIndex <= 0)
            {
                return null;
            }
            else
            {
                return stateList.SelectedValue;
            }
        }
    }

    public string subSateName
    {
        get
        {
            if (subName.Value != "" && subName.Value.IndexOf("所有区") == -1)
                return subName.Value.Split('-')[0];
            else
                return null;
        }
    }
    public string subSateId
    {
        get
        {
            if (subName.Value != "" && subName.Value.IndexOf("所有区") == -1)
                return subName.Value.Split('-')[1];
            else
                return null;
        }
    }

    public SqlDataReader dr2 = null;
    void init()
    {
        DataSet dr = DAL.SqlHelper.Query("select distinct trade_id,trade_name from dbo.enterprise_Trade_sub");
        stateList.DataSource = dr;
        stateList.DataTextField = "trade_name";
        stateList.DataValueField = "trade_id";
        stateList.DataBind();
        stateList.Items.Insert(0, new ListItem("所有城市", "0"));

dr2 = DAL.SqlHelper.ExecuteReader("select distinct trade_sub_id,trade_sub_name, trade_id,trade_name from dbo.enterprise_Trade_sub");

        int indx = 0;
        if (dr2 != null)
        {
            StringBuilder sb = new StringBuilder();
            while (dr2.Read())
            {
                sb.Append("states[");
                sb.Append(indx);
                sb.Append("]=new subState(");
                sb.Append(dr2["trade_sub_id"].ToString());
                sb.Append(",'");
                sb.Append(dr2["trade_sub_name"].ToString());
                sb.Append("',");
                sb.Append(dr2["trade_id"].ToString());
                sb.Append(");");

                indx++;
            }
            str.Value = sb.ToString();
            dr2.Close();

}

}
}