请帮忙，100分在线等！

Question

DropDownList1 绑定 SqlDataSource1  AutoPostBack="True"
DropDownList2 绑定 SqlDataSource2，由 DropDownList1 传入参数，AutoPostBack="True"GridView1 绑定 SqlDataSource3，由 DropDownList2 传入参数，现在问题是，GridView1总不能保持最新数据显示，
想在DropDownList2 或 SqlDataSource2 数据render以后再更新、执行  SqlDataSource3.databind()
但不知道该如何写，
请指教，多谢了！

Answer 1

GridView1.DataSource = SqlDataSource3;
GridView1.Databind;

Answer 2

哦，刚看明白你的意思。
那我认为你可以在DropDownList2 的SelectedIndexChanged事件中绑定GridView1

Answer 3

dropdownlist1_onchange:
  bind_dropdownlist2;
  bind_dropdownlist3;dropdownlist2_onchange:
  bind_dropdownlist3;

Answer 4

当改变最后一个DorpDownList时重新绑定你检索的数据集

Answer 5

DropDownList2改变，Gridview当然会改变，
关键时DropDownList1改变时，DropDownList2会改变，但Gridview不是每次都能及时改变的。
代码如下：
<asp:SqlDataSource ID="college" runat="server" ConnectionString="<%$ ConnectionStrings:newdata-cetConnectionString %>" SelectCommand="SELECT [dm_mc], [xy_dm] FROM [a_xy]"  ></asp:SqlDataSource><asp:SqlDataSource ID="depart" runat="server" ConnectionString="<%$ ConnectionStrings:newdata-cetConnectionString %>" SelectCommand="SELECT [zy_dm], [dm_mc] FROM [a_zy] where [zy_dm] Like @zy_dm" >
  <SelectParameters>
    <asp:ControlParameter ControlID="DropDownList1" Name="zy_dm" PropertyName="Value" />
  </SelectParameters>
</asp:SqlDataSource><asp:SqlDataSource ID="detail" runat="server" ConnectionString="<%$ ConnectionStrings:newdata-cetConnectionString %>"
            SelectCommand="SELECT [姓名], [ID], [学号], [证件号码], [报考级别], [fee] FROM [dida_cet] where 报考级别=@band) order by ID">
            <SelectParameters>
                <asp:ControlParameter ControlID="DropDownList2" DefaultValue="" Name="band" PropertyName="SelectedValue" />
            </SelectParameters>
        </asp:SqlDataSource> <asp:DropDownList ID="DropDownList1"
                runat="server" DataSourceID="college" DataTextField="dm_mc" DataValueField="xy_dm" AutoPostBack=true>
            </asp:DropDownList>
            
<asp:DropDownList ID="DropDownList2" runat="server"
                  DataSourceID="depart" DataTextField="dm_mc" DataValueField="zy_dm" AutoPostBack=true >
              </asp:DropDownList>        <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False"
            DataKeyNames="ID" DataSourceID="detail" Width="300" AllowSorting="True">
            <Columns>
                <asp:BoundField DataField="ID" HeaderText="流水号" ReadOnly="True" SortExpression="ID" />
            </Columns>
        </asp:GridView>

Answer 6

搞掂：
    protected void tester_college_SelectedIndexChanged(object sender, EventArgs e)
    {
        depart.DataBind();
        tester_spec.DataBind();
        detail.DataBind();
        GridView1.DataBind();
    }