dropdownlist 二级联动取值

[bychgh]

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))
        {
            ChannelNo = Convert.ToInt32(this.ddl_Channel.SelectedItem.Value);
            bingClass();   //第二个
           
        }
}
    public void bingClass()
    {
        this.ddl_Class.Items.Clear();
        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));
            }
        }
       
           //这里第一个dropdownlist 如果选第一项，classno都为1，选其他正常
        ClassN0 = Convert.ToInt32(this.ddl_Class.SelectedValue.ToString());
       
    }

    protected void ddl_Channel_SelectedIndexChanged(object sender, EventArgs e)
    {
        bingClass();
    }

不管是否第一次加载页面，2个dropdownlist 数据都能读出来，但选第一个dropdownlist 的第一个值，第二个dropdownlist 项的value 都是1，选第一个dropdownlist 的其他项，第二个dropdownlist 中项的value 能正常获取，帮忙看看怎么改~~~~~~~~~~

[智者知已应修善业]

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

[wuyq11]

<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

[MSDNXGH]

明白你的意思，就看得有点迷湖。。。。

[rwm5366745]

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));
}
}
}

[bychgh]

还是不对~~~~~~~

[酷儿]

说明白一点

[daone]

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

[sangenmutou]

if (!IsPostBack)绑定的时候不要写在这里面

[bychgh]

多谢~~~~~~~