Question

我有两个下拉列表，其中一个是＆＃34; State＆＃34;另一个是＃34; Cluster＆＃34;。这两个下拉列表都是关系型的。例如，如果我在州选择喀拉拉邦，那么群集将填充其重要城市和dist。像Pathnamthitta，calicut，palakad等。

所以，我想要的是，我想给出一个选项＆＃34; Select All＆＃34;在州和群ddl。

我经历过：

How to select all records in a DropDownList

http://www.w3schools.com/aspnet/control_dropdownlist.asp

http://forums.asp.net/t/1221977.aspx?Adding+a+Select+all+option+to+a+drop+down+list

但他们都没有为我工作。我可以选择所有状态，但不能在其他ddl上填充聚类值。

这是我的代码＆＃34; State＆＃34; DDL：

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataSet3TableAdapters.tbl_energy_reportTableAdapter state;
state = new DataSet3TableAdapters.tbl_energy_reportTableAdapter();
DataTable dt = new DataTable();
dt = state.GetDataByStateInnerJoin();
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "state1";
DropDownList1.DataValueField = "state1";
DropDownList1.DataBind();                
DropDownList1.Items.Insert(0, new System.Web.UI.WebControls.ListItem("--Select State--", "0"));
DropDownList2.Items.Insert(0, new System.Web.UI.WebControls.ListItem("--Select Cluster--", "0"));
}
}

此代码适用于＆＃34; Cluster＆＃34;

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{

DataSet3TableAdapters.tbl_energy_reportTableAdapter state;
state = new DataSet3TableAdapters.tbl_energy_reportTableAdapter();
DataTable dt = new DataTable();
dt = state.GetDataByClusterInnerJoin(DropDownList1.SelectedValue);
DropDownList2.DataSource = dt;
DropDownList2.DataTextField = "cluster";
DropDownList2.DataValueField = "cluster";
DropDownList2.DataBind();

}

这是State ddl：

的查询

SELECT DISTINCT tbl_site_details.state1
FROM            tbl_site_details INNER JOIN
                         tbl_energy_report ON tbl_energy_report.Site_ID = tbl_site_details.site_id

这是Cluster ddl：

的查询

SELECT        tbl_site_details.cluster
FROM            tbl_site_details INNER JOIN
                         tbl_energy_report ON tbl_energy_report.Site_ID = tbl_site_details.site_id
WHERE        (tbl_site_details.state1 = @state1)

Answer 1

那是因为在ddl1_selectedindexchanged方法上使用dt重新绑定ddl2。

评论＆＃39; DropDownList2.Items.Insert＆＃39;在你的page_load上

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataSet3TableAdapters.tbl_energy_reportTableAdapter state;
state = new DataSet3TableAdapters.tbl_energy_reportTableAdapter();
DataTable dt = new DataTable();
dt = state.GetDataByStateInnerJoin();
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "state1";
DropDownList1.DataValueField = "state1";
DropDownList1.DataBind();                
DropDownList1.Items.Insert(0, new System.Web.UI.WebControls.ListItem("--Select State--", "0"));
//COMMENT THIS LINE
//DropDownList2.Items.Insert(0, new System.Web.UI.WebControls.ListItem("--Select Cluster--", "0"));
}
}

并将其移至dropdownlist1_selectedindexchanged事件。

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{

DataSet3TableAdapters.tbl_energy_reportTableAdapter state;
state = new DataSet3TableAdapters.tbl_energy_reportTableAdapter();
DataTable dt = new DataTable();
dt = state.GetDataByClusterInnerJoin(DropDownList1.SelectedValue);
DropDownList2.DataSource = dt;
DropDownList2.DataTextField = "cluster";
DropDownList2.DataValueField = "cluster";
DropDownList2.DataBind();

//put it here
DropDownList2.Items.Insert(0, new System.Web.UI.WebControls.ListItem("--Select Cluster--", "0"));
}

Answer 2

最好使用Ajax调用来填充第二个下拉列表。使用包含选定ID的搜索字符串向服务器发送请求，并使用结果填充第二个下拉列表。将结果作为json对象返回。

＆＃34;全选＆＃34;两个或多个下拉列表的选项

2 个答案: