AspxGridView里的Templates里的DetailsView里的一个button单击如果去获取另一个兄弟控件?

<Templates>
<DetailRow>
<div style="overflow:hidden;line-height:23px;margin-bottom:5px;">
<span style="float:left;"><%# Eval("Name") %>地区价格表:</span>
<dx:ASPxButton ID="btnExpressAreaAdd" runat="server" Text="新增地区价格" OnClick="btnExpressAreaAdd_Click" style="float:right;">
<Paddings Padding="0" />
</dx:ASPxButton>
</div>
<dx:ASPxGridView ID="agvExpressArea" runat="server" SkinID="agvDetailSkin" Width="100%" OnBeforePerformDataSelect="agvExpressArea_BeforePerformDataSelect">
<Columns>
<dx:GridViewDataTextColumn Caption="运达地区" FieldName="Area" VisibleIndex="0"></dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn Caption="首重价格(元)" FieldName="FirstCost" VisibleIndex="1"></dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn Caption="续重价格(元)" FieldName="NextCost" VisibleIndex="2">
</dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn Caption="类型" FieldName="ItemType" VisibleIndex="3">
</dx:GridViewDataTextColumn>
<dx:GridViewCommandColumn Caption="操作" HeaderStyle-HorizontalAlign="Center" Width="60" VisibleIndex="4">
<DeleteButton Text="删除" Visible="true" />
</dx:GridViewCommandColumn>
</Columns>
</dx:ASPxGridView>
</DetailRow>
</Templates>