刷新asp.net中的下拉列表数据源 [英] Refresh dropdownlist data source in asp.net

问题描述

大家好，



我想在源表中更改数据时刷新asp.net中的下拉列表数据源。





我正在使用弹出窗口在表格中添加新条目，并且条目完全成功提交。但是当我关闭弹出窗口时，dropdownlist中的数据保持不变。新值不会显示在下拉列表中。



如果我刷新页面，则删除先前文本框中输入的数据，我需要重新输入所有数据。



请帮帮我...



提前付款......

试试这个：

 protected void Page_Load（object sender，EventArgs e）
 {
 if（！IsPostBack）
 {
 string str = ConfigurationManager.ConnectionStrings [Class28ConnectionString]。ToString（）; 
 SqlConnection con = new SqlConnection（str）; 
 string sql =select * from t_c; 
 SqlCommand cmd = new SqlCommand（sql，con）; 
 con.Open（）; 
 
 SqlDataReader rdr = cmd.ExecuteReader（）; 
 while（rdr.Read（））
 {
 ListItem lst = new ListItem（）; 
 lst.Text = rdr [1] .ToString（）; 
 lst.Value = rdr [0] .ToString（）; 
 DropDownList1.Items.Add（lst）; 
} 
 DropDownList1.DataSource = rdr; 
 DropDownList1.Items.Insert（0，new ListItem（select，0））; 
 
} 
} 
 

从弹出窗口刷新父页面， 
然后将下拉列表项绑定在！回发。 
 
 protected void Page_Load（object sender，EventArgs e）
 {
 if（！IsPostBack）
 {
 SqlConnection con = new SqlConnection（Data Source =; Database =; User ID =; Password = !; Asynchronous Processing = true）; 
 con.Open（）; 
 SqlCommand cmd = new SqlCommand（select contacts first from contacts，con）; 
 SqlDataAdapter dtAdapter = new SqlDataAdapter（cmd）; 
 DataTable dt = new DataTable（）; 
 dtAdapter.Fill（dt）; 
 ddl1.DataSource = dt; 
 ddl1.DataTextField =firstName; 
 ddl1.DataValueField =firstName; 
 ddl1.DataBind（）; 
 ddl1.Items.Insert（0，new ListItem（select，0））; 
} 
} 

Hello guys,

I want to refresh dropdownlist data source in asp.net when data is changed in source table.


I am using popup window to add new entry in table and entry is submited success fully. but when I close the popup window data in dropdownlist remains same. New value doesnot displaying in drop down list.

and if I refresh page then data entered in previous textboxes is removed and I need to re enter all data.

Please help me...

Thanx in advance....

解决方案

try this:

protected void Page_Load(object sender, EventArgs e)
   {
        if (!IsPostBack)
       {
           string str = ConfigurationManager.ConnectionStrings["Class28ConnectionString"].ToString();
           SqlConnection con = new SqlConnection(str);
           string sql = "select * from t_c";
           SqlCommand cmd = new SqlCommand(sql, con);
           con.Open();

           SqlDataReader rdr = cmd.ExecuteReader();
           while (rdr.Read())
           {
               ListItem lst = new ListItem();
               lst.Text = rdr[1].ToString();
               lst.Value = rdr[0].ToString();
               DropDownList1.Items.Add(lst);
           }
           DropDownList1.DataSource = rdr;
           DropDownList1.Items.Insert(0, new ListItem("select", "0"));

       }
   }

Refresh the parent page from popup window, 
Then Bind the dropdownlist items on !is post back.

protected void Page_Load(object sender, EventArgs e)
    {
         if (!IsPostBack)
        {
SqlConnection con = new SqlConnection("Data Source=;Database=;User ID=;Password=!;Asynchronous Processing=true");
con.Open();
            SqlCommand cmd = new SqlCommand("select firstname from contacts", con);
            SqlDataAdapter dtAdapter = new SqlDataAdapter(cmd);
            DataTable dt= new DataTable();
            dtAdapter.Fill(dt);
            ddl1.DataSource = dt;
            ddl1.DataTextField = "firstName";
            ddl1.DataValueField = "firstName";
            ddl1.DataBind();
            ddl1.Items.Insert(0, new ListItem("select", "0"));
         }
    }

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