如何在嵌套的gridview行命令中获取下拉列表的选定值

Question

如何在嵌套的gridview行命令中获取dropdownlist的选定值。

我的页面中有一个嵌套的gridview，在第二个gridview中我想使用Driver的下拉列表。我试图获取该下拉列表的选定值，但无法在gridview rowcommand中获取它。我也尝试按钮点击事件，但我无法得到它。

<asp:GridView ID="dtgNewTrips" runat="server" AllowPaging="true" AutoGenerateColumns="false" CssClass="table table-striped table-bordered table-hover" OnRowDataBound="dtgNewTrips_RowDataBound" DataKeyNames="Trips_ID">
  <Columns>
    <asp:TemplateField ItemStyle-Width="20px">
      <ItemTemplate>
        <a href="JavaScript:ViewDetails('div<%# Eval(" Trips_ID ") %>');">
                                            <img alt="City" id="imgdiv<%# Eval("Trips_ID") %>" src="Images/Icons/plusicon.png" />
                                        </a>
        <div id="div<%# Eval(" Trips_ID ") %>" style="display: none;">
          <asp:GridView ID="dtgViewDetails" runat="server" AutoGenerateColumns="false" DataKeyNames="Trips_ID" CssClass="ChildGrid" ShowHeader="false" OnRowDataBound="dtgViewDetails_RowDataBound" OnRowCommand="dtgViewDetails_RowCommand">
            <Columns>
              <asp:TemplateField ShowHeader="false">
                <ItemTemplate>
                  <div>
                    <table style="width: 100%;">
                      <tr>
                        <td>Adults:
                          <asp:Label ID="lblTrip_ID" runat="server" Text='<%#Eval("Trips_ID") %>' Visible="false"></asp:Label>
                          <asp:Label ID="Label1" runat="server" Text='<%#Eval("AdultsCount") %>'></asp:Label>
                        </td>
                        <td>Children:
                          <asp:Label ID="Label2" runat="server" Text='<%#Eval("ChildrensCount") %>'></asp:Label>
                        </td>
                        <td>Passenger Comments:
                          <asp:Label ID="Label4" runat="server" Text='<%#Eval("PassengerComments") %>'></asp:Label>
                        </td>
                      </tr>
                      <tr>
                        <td>Trip Stops:</td>
                        <td>
                          <asp:Label ID="Label3" runat="server" Text='<%#Eval("TripStops") %>'></asp:Label>
                        </td>
                        <td>TripStops Comments:
                          <asp:Label ID="Label5" runat="server" Text='<%#Eval("TripStopsComments") %>'></asp:Label>
                        </td>
                      </tr>
                      <tr>
                        <td>
                          <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                            <ContentTemplate>
                              <asp:DropDownList ID="ddlDriver" runat="server" DataTextField="DriverName" DataValueField="DriversInfo_ID" CssClass="form-control" AutoPostBack="false"></asp:DropDownList>
                            </ContentTemplate>
                          </asp:UpdatePanel>
                        </td>
                        <td>
                          <asp:Button ID="btnAssign" runat="server" Text="Assign To Driver" CssClass="btn btn-primary" CommandArgument='<%# ((GridViewRow)Container).RowIndex %>' CommandName="Assign" />
                        </td>
                        <td>
                          <asp:Button ID="btnAssignToAll" runat="server" OnClick="btnAssignToAll_Click" Text="Notify All Drivers" CssClass="btn btn-primary" />
                          <asp:Button ID="btnCancelTrip" runat="server" OnClick="btnCancelTrip_Click" Text="Cancel Trip" CssClass="btn btn-warning" />&nbsp;
                        </td>
                      </tr>
                    </table>
                  </div>
                </ItemTemplate>
              </asp:TemplateField>
            </Columns>
          </asp:GridView>
        </div>
      </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Trip No">
      <ItemTemplate>
        <asp:Label ID="lblTripRefID" runat="server" Text='<%#Eval("TripRefID") %>'></asp:Label>
      </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Customer Name">
      <ItemTemplate>
        <asp:Label ID="lblCompanyName" runat="server" Text='<%#Eval("CompanyName") %>'></asp:Label>
      </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Pickup Location">
      <ItemTemplate>
        <asp:Label ID="lblPickupLocation" runat="server" Text='<%#Eval("PickupLocation") %>'></asp:Label>
      </ItemTemplate>
    </asp:TemplateField>
  </Columns>
</asp:GridView>

C＃代码

protected void dtgViewDetails_RowCommand(object sender, GridViewCommandEventArgs e)
 {
    if (e.CommandName == "Assign")
    {
        int rowIndex = Convert.ToInt32(e.CommandArgument);
        GridView grid = (GridView)sender;
        if (grid.ID == "dtgViewDetails")
        {
            Label lblTrip_ID = (Label)grid.Rows[rowIndex].FindControl("lblTrip_ID");
            DropDownList ddlDriver = (DropDownList)grid.Rows[rowIndex].FindControl("ddlDriver");
        }
    }
 }

但是我得到了默认的dropdownlist，这是第0个索引值。 请帮我.. 提前谢谢..