在删除之前如何显示正在加载的 gif?

how can I show loading gif until deleting?

我在 update panel 中的 repeater 上有一个删除按钮。当我点击delete button时,它可以删除,但是大约需要10秒。所以我想添加一个 loading gif 。我是添加 gif 的初学者。请帮我。感谢您的关注

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString='<%$ ConnectionStrings:NET2ConnectionString %>' SelectCommand="SELECT * FROM [ProductsRA]"></asp:SqlDataSource>
                <asp:Repeater ID="rptuser" runat="server" DataSourceID="SqlDataSource1" OnItemCommand="rpr1_ItemCommand" OnItemDataBound="rpr1_ItemDataBound">
                    <ItemTemplate>
                        <tr>
                            <td class="GridItems">
                                <asp:ImageButton runat="server" ID="delbtn" ImageUrl="~/images/delete.gif" CommandName="Delete" CommandArgument='<%# Eval("ID") %>' ValidationGroup="ab" ToolTip="Delete User" /></td>
                            <td class="GridItems"><%# DataBinder.Eval(Container.DataItem,"ID") %></td>
                            <td class="GridItems"><%# DataBinder.Eval(Container.DataItem,"ProductName") %></td>
                            <td class="GridItems"><%# DataBinder.Eval(Container.DataItem,"Quantity") %></td>
                            <td class="GridItems"><%# DataBinder.Eval(Container.DataItem,"UnitPrice") %></td>
                            <td class="GridItems">
                            </td>
                        </tr>
                    </ItemTemplate>
                    <FooterTemplate>
                        </table>
                    </FooterTemplate>
                </asp:Repeater>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="rptuser" />
            </Triggers>
        </asp:UpdatePanel>

这是 CS:

 protected void rpr1_ItemCommand(object source, RepeaterCommandEventArgs e)
{
    DataSet.ProductsRADataTable dt = new DataSet.ProductsRADataTable();
    DataSetTableAdapters.ProductsRATableAdapter adp = new DataSetTableAdapters.ProductsRATableAdapter();

    if (e.CommandName == "Delete")
    {
       adp.DeleteQuery(Convert.ToInt32(e.CommandArgument));
    }
}

您可以为此使用 UpdateProgess control

<asp:UpdateProgress ID="UpdateProgress1" runat="server"
        AssociatedUpdatePanelID="UpdatePanel1">
    <ProgressTemplate>
        <div class="loading_div">            
            <p>Please wait while we process the request.</p>
            <img src="/Images/loader.gif" />
        </div>
    </ProgressTemplate>
</asp:UpdateProgress>

如果您想在处理请求时阻止页面,请使用叠加层 div。

.loading_div {
    position: absolute;
    color:#fff;
    background-color: #000;
    z-index: 2000 !important;
    opacity: 0.6;
    overflow: hidden;
    text-align: center;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    padding-top:20%;
}

处理请求时会这样渲染:http://jsfiddle.net/codeandcloud/jLmbmLmn/