如何在 asp.net 中为多选创建 SelectedIndexChanged 事件

Question

我想从复选框列表中选择多个项目，然后在第一个复选框列表的选择索引更改事件上填充另一个复选框列表，但是在一次选择后，由于"Auto Post Back = true"，它不适用于另一个选定的项目，而调试时我可以看到指针从页面加载事件开始。我希望在选择所有项目后应该触发 "ddlregion_SelectedIndexChanged" 以便我可以在另一个复选框列表中看到所有选定的项目相关值。

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                BindRegion();
            }
        }

因此它没有为其他选定的项目获取数据如何解决这个问题请帮助我。

ddlRegion 代码绑定：

public void BindRegion()
        {
            OracleCommand Cmd = new OracleCommand("select * from regions", con);
            Cmd.CommandType = CommandType.Text;
            OracleDataAdapter da = new OracleDataAdapter();
            DataSet ds = new DataSet();
            da.SelectCommand = Cmd;
            da.Fill(ds);
            ddlregion.DataSource = ds;
            ddlregion.DataTextField = "REGION_DESC";
            ddlregion.DataValueField = "REGION_CODE";
            ddlregion.DataBind();

        }

选择索引更改事件

 protected void ddlregion_SelectedIndexChanged(object sender, EventArgs e)
 {
  ddlDepot.Items.Clear();
  ddlDepot.Items.Add(new ListItem("--Select Depot--", ""));
  foreach (ListItem item in ddlregion.Items)
   {

   if (item.Selected == true)
   {
string str = "select d.depot_code, d.depot_description from regions r, sub_regions sr, depots d where r.region_code = sr.region_code and sr.sub_region_code = d.sub_region_code and active = 'Y' and r.region_code in " + ddlregion.SelectedValue + "";
                    OracleCommand Cmd = new OracleCommand(str, con);
                    Cmd.CommandType = CommandType.Text;
                    OracleDataAdapter da = new OracleDataAdapter();
                    DataSet ds = new DataSet();
                    da.SelectCommand = Cmd;
                    da.Fill(ds);
                    ddlDepot.DataSource = ds;
                    ddlDepot.DataTextField = "DEPOT_DESCRIPTION";
                    ddlDepot.DataValueField = "DEPOT_CODE";
                    ddlDepot.DataBind();
                }
            }
        }

Answer 1

您需要为 SQL 构建您的区域列表，然后在完成后调用您的 SQL 并绑定。

 string regions = "";
 bool regionSelected = false;
  foreach (ListItem item in ddlregion.Items)
  {  
   if (item.Selected == true)
    {
        regions += item.SelectedValue + ",";
        regionSelected = true;
    }
 
  } 
     // looping done so clean up string for SQL
     regions = "(" + regions.TrimEnd(',') + " )";

 //only run if a region is selected
 if(regionSelected)
 {
 string str = "select d.depot_code, d.depot_description from regions r, sub_regions sr, 
 depots d where r.region_code = sr.region_code and      
 sr.sub_region_code = d.sub_region_code and active = 'Y' and  r.region_code    
 in " + regions;
                OracleCommand Cmd = new OracleCommand(str, con);
                Cmd.CommandType = CommandType.Text;
                OracleDataAdapter da = new OracleDataAdapter();
                DataSet ds = new DataSet();
                da.SelectCommand = Cmd;
                da.Fill(ds);
                ddlDepot.DataSource = ds;
                ddlDepot.DataTextField = "DEPOT_DESCRIPTION";
                ddlDepot.DataValueField = "DEPOT_CODE";
                ddlDepot.DataBind();
 }