Asp.net 子图形GDirection未显示在网页上

我在我的网页上使用subgurim，我试图获得填充的方向。我已经正确地显示了标记。我没有在添加方向的过程中，但我不明白为什么不显示方向

以下是网页：

<%@ register assembly="GMaps" namespace="Subgurim.Controles" tagprefix="cc1" %>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
<table align="center" width="80%" border="0" cellspacing="0" cellpadding="0">
<tr>
    <td align="center" valign="top" width="10%">
        <asp:Label ID="lblDirectionsFrom" runat="server" CssClass="Label" Text="Drive From:" Visible="False"></asp:Label>
        &nbsp;
        <asp:DropDownList ID="ddlDirectionsFrom" runat="server" CssClass="Textbox" Width="100px" AppendDataBoundItems="True" Visible="false" AutoPostBack="True">
        </asp:DropDownList>
        &nbsp;
    </td>
    <td align="center" valign="top" width="20%" colspan="3">
        <asp:Label ID="lblDirectionsTo" runat="server" CssClass="Label" Text="Drive To:" Visible="False"></asp:Label>
        &nbsp;
        <asp:DropDownList ID="ddlDirectionsTo" runat="server" CssClass="Textbox" Width="100px" AppendDataBoundItems="True" Visible="false" AutoPostBack="True">
        </asp:DropDownList>
    </td>
    <td align="left" valign="top" colspan="4" width="40%">
        <input type="button" id="bt_Go" runat="server" value="Get Directions" onserverclick="GetDirections" class="CmdButton" visible="False" />
    </td>
</tr>
<tr>
    <td align="right" valign="top" width="10%">
    </td>
    <td align="left" valign="top" width="20%" colspan="3">
    </td>
    <td align="left" valign="top" colspan="4" width="40%">
        <asp:Label ID="txtMapMsg"
            runat="server"
            Text="txtMapMsg"
            CssClass="Msgbox"
            Width="80%"
            Visible="False"
            BackColor="#F7B432"></asp:Label>
    </td>
</tr>
<tr>
    <td align="center" valign="top" colspan="4" width="60%">
        <asp:TextBox ID="tb_fromPoint" runat="server" meta:resourcekey="tb_fromPointResource1"></asp:TextBox>
        <asp:TextBox ID="tb_endPoint" runat="server" meta:resourcekey="tb_endPointResource1"></asp:TextBox>
        <cc1:GMap ID="GMap1" runat="server" Key="googlemaps.subgurim.net" CommercialKey="googlemaps.subgurim.net_Commercial" enableServerEvents="true" />
        <div id="div_directions"></div>
    </td>
    <td align="center" valign="top" colspan="4" width="40%">            
    </td>
</tr>
    </table>
</asp:Content>

---

我没有得到任何错误和方向。任何帮助都将不胜感激。

过了一段时间，我回来发现我做错了什么

NavcareDirection = New GDirection()
NavcareDirection.autoGenerate = False
NavcareDirection.buttonElementId = "bt_Go"
NavcareDirection.fromElementId = tb_fromPoint.ClientID
NavcareDirection.toElementId = tb_endPoint.ClientID
NavcareDirection.divElementId = "div_directions"
NavcareDirection.clearMap = True

NavcareDirection.errorMessage = "Directions Error"

GMap1.Add(NavcareDirection)

到了那里，我终于收到了错误消息，但我不知道为什么会收到这些消息。我将把它放到一个新问题中

NavcareDirection = New GDirection()
NavcareDirection.autoGenerate = False
NavcareDirection.buttonElementId = "bt_Go"
NavcareDirection.fromElementId = tb_fromPoint.ClientID
NavcareDirection.toElementId = tb_endPoint.ClientID
NavcareDirection.divElementId = "div_directions"
NavcareDirection.clearMap = True

NavcareDirection.errorMessage = "Directions Error"

GMap1.Add(NavcareDirection)