Question

我想创建一个加载屏幕，但是当我触发selectedindexchanged时，代码将在同一时间执行所有代码，因此它只加载了很长时间，我想做的就是选择下拉菜单的选项，然后显示通过在页面加载过程中使“覆盖屏幕”可见，从而加载屏幕，我尝试了一些不同的操作，包括javascript和System.Threading.Thread.Sleep(22);，但是没有运气，在此先感谢您的时间。

<div id="loading">
        <div id="coverScreen" class="LockOn">
        </div>
    </div>
<asp:DropDownList ID="DropDown" DataValueField="IDCoContratante" DataTextField="Designation" runat="server" Enabled="true" CssClass="dropdownCocont" Style="border-radius: 7px; border-style: none;" AutoPostBack="true" OnSelectedIndexChanged="DropDown_ListarPropostas_SelectedIndexChanged"></asp:DropDownList>



protected void DropDown_ListarPropostas_SelectedIndexChanged(object sender, EventArgs e)
        {

            //Response.Write("<script>document.getElementById('coverScreen').style.visibility = 'visible';</script>");
            coverScreen.Visible = true;




            System.Threading.Thread.Sleep(22);

            ClassConn c = new ClassConn();
            c.OpenConection();

            DataTable dt = new DataTable();


            //SqlDataAdapter AtualizaDropLotes = new SqlDataAdapter(" SELECT dbo.TblLoteCoContratanteAdjudicado.IDLote, CAST(dbo.TblLote.NrLote AS varchar) + '  ' + dbo.TblLote.DescricaoLote AS DescricaoLote, dbo.TblLote.IDAcordoQuadro " +
            //                                                      " FROM dbo.TblLoteCoContratanteAdjudicado INNER JOIN dbo.TblLote ON dbo.TblLoteCoContratanteAdjudicado.IDLote = dbo.TblLote.IDLote AND dbo.TblLoteCoContratanteAdjudicado.IDLote = dbo.TblLote.IDLote " +
            //                                                      " WHERE (dbo.TblLote.IDAcordoQuadro = '" + DropDownAcordosQuadros_ListarPropostas.SelectedValue + "') " +
            //                                                      " GROUP BY dbo.TblLoteCoContratanteAdjudicado.IDLote, CAST(dbo.TblLote.NrLote AS varchar) + '  ' + dbo.TblLote.DescricaoLote, dbo.TblLote.IDAcordoQuadro", c.con);
            string _query = "SELECT '%' as IDLote, 'Todos' as DescricaoLote UNION ALL SELECT CAST(dbo.TblLoteCoContratanteAdjudicado.IDLote AS VARCHAR), 'Nº' + CAST(dbo.TblLote.NrLote AS varchar) + ' - ' + dbo.TblLote.DescricaoLote AS DescricaoLote FROM dbo.TblLoteCoContratanteAdjudicado INNER JOIN dbo.TblLote ON dbo.TblLoteCoContratanteAdjudicado.IDLote = dbo.TblLote.IDLote AND dbo.TblLoteCoContratanteAdjudicado.IDLote = dbo.TblLote.IDLote WHERE(dbo.TblLoteCoContratanteAdjudicado.NIFCoContratante = '" + id_Vat + "') AND(dbo.TblLote.IDAcordoQuadro = '" + DropDownAcordosQuadros_ListarPropostas.SelectedValue + "')";

            SqlDataAdapter AtualizaDropLotes = new SqlDataAdapter(_query, c.con);

            AtualizaDropLotes.Fill(dt);

            if (dt != null)
            {
                DropDownLotes_ListaPropostas.DataSource = dt;
                DropDownLotes_ListaPropostas.DataBind();


            }

            c.CloseConnection();
            coverScreen.Visible = false;
        }

Answer 1

根据Alex Kudryashev和Gus给我的信息，我能够找到解决问题的方法，就是：

我将加载屏幕插入了asp：UpdatePanel之间，顶部是asp：ScriptManager。

<asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>

        <asp:UpdateProgress ID="UpdateProgress1" runat="server">
            <ProgressTemplate>
                <div id="coverScreen" class="LockOn" runat="server">
                </div>
            </ProgressTemplate>
        </asp:UpdateProgress>

然后我在主div中插入了以下代码

<div id="Main">
 <asp:UpdatePanel ID="UpdatePanel2" runat="server">
            <ContentTemplate>

//your code

    </ContentTemplate>
  </asp:UpdatePanel>
</div>

在选择索引更改的同时显示加载屏幕

1 个答案: