dropdownlist 二级联动取值

Question

本帖最后由 bychgh 于 2010-10-08 10:38:10 编辑

Answer 1

<asp:ScriptManager ID="ScriptManager1" runat="server">
  </asp:ScriptManager>
  <div>
  <asp:UpdatePanel ID="UpdatePanel1" runat="server">
  <ContentTemplate>
  <asp:DropDownList ID="ddlLB" runat="server" Width="15%" AutoPostBack="True" OnSelectedIndexChanged="ddlLB_SelectedIndexChanged">
  </asp:DropDownList>
  <asp:DropDownList ID="ddlChild" runat="server" Width="20%">
  </asp:DropDownList>
  </ContentTemplate>
  </asp:UpdatePanel>
  </div>   
protected void ddlLB_SelectedIndexChanged(object sender, EventArgs e)
  {
  if(this.ddlLB.SelectedValue!=null)
  {
  BindChild(this.ddlLB.SelectedValue);
  }
  }
SelectedValue变化才能获取值

Answer 2

protected void Page_Load(object sender, EventArgs e)
    {
       if (!IsPostBack)
        {
            //  第一个dropdownlist   ,AutoPostBack="true"    
            this.ddl_Channel.DataSource = new BLL.NMG_Article_Channel().GetAllList();
            this.ddl_Channel.DataTextField = "ch_name";
            this.ddl_Channel.DataValueField = "ch_id";
            this.ddl_Channel.DataBind();
           
        }
 
 if (!string.IsNullOrEmpty(this.ddl_Channel.SelectedValue))
    {
        bingClass();            
    }
}  public void bingClass()
    {
      this.ddl_Class.Items.Clear();
      ClassN0 = Convert.ToInt32(this.ddl_Class.SelectedValue.ToString());
     if (!string.IsNullOrEmpty(ChannelNo.ToString()))
      {
        DataTable Dt = new BLL.NMG_Article_Class().GetNewsClass(ChannelNo).Tables[0];
        for (int i = 0; i < Dt.Rows.Count; i++)
        {
            string c_id = Dt.Rows[i]["cl_id"].ToString();
            string c_name = Dt.Rows[i]["cl_name"].ToString();
            this.ddl_Class.Items.Add(new ListItem(c_name, c_id));
         }
       }
    }

Answer 3

修改
if (this.ddl_Channel.SelectedIndex != -1)
{
            //ChannelNo = Convert.ToInt32(this.ddl_Channel.SelectedItem.Value);
            bingClass();   //第二个           
}应该是ChannelNo这个中间变量的关系.使用DDL的index就好了 -1 代表没选

Answer 4

 if (!IsPostBack)绑定的时候不要写在这里面

Answer 5

http://blog.csdn.net/xianfajushi/archive/2010/10/08/5928136.aspx