我在这里找到了http://forums.asp.net/p/1331581/2678206.aspx

<asp:TemplateField ShowHeader="False">
            <ItemTemplate>
                <asp:ImageButton ID="DeleteButton" runat="server" ImageUrl="~/site/img/icons/cross.png"
                    CommandName="Delete" OnClientClick="return confirm('Are you sure you want to delete this event?');"
                    AlternateText="Delete" />               
            </ItemTemplate>
        </asp:TemplateField>