從下拉列表中選擇數據而無需刷新頁面

Question

在我的應用程序中，當我從下拉列表（ddlcategory）中選擇類別時，數據將綁定在純度下拉列表（ddlpurity）中。但是頁面正在刷新。所以我使用了更新面板來解決此（頁面刷新）問題。選擇ddlcategory中的數據時，數據未綁定到ddlpurity。如何在不刷新頁面的情況下將數據綁定到ddlpurity。

ASP設計頁面

<asp:ScriptManager ID="ScriptManager1" runat="server"> </asp:ScriptManager>
<asp:UpdatePanel runat="server" id="UpdatePanel" updatemode="Conditional">
 <Triggers>
     <asp:Asyncpostbacktrigger controlid="ddlcategory" eventname="SelectedIndexChanged" />
   </Triggers>
       <ContentTemplate>
             <asp:DropDownList ID="ddlcategory" class="form-control txtboxmargin validate[required]" runat="server" 
               AutoPostBack="True" onselectedindexchanged="ddlcategory_SelectedIndexChanged" AppendDataBoundItems="True">
             <asp:ListItem Value="">--select category--</asp:ListItem>
           </asp:DropDownList>
       </ContentTemplate>

   </asp:UpdatePanel>

<asp:DropDownList ID="ddlpurity" 
               class="form-control txtboxmargin" AutoPostBack="True" runat="server"
               onselectedindexchanged="ddlpurity_SelectedIndexChanged">
           </asp:DropDownList>

C＃代碼：

protected void ddlcategory_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (ddlcategory.SelectedItem.Text == "Gold")
        {
            BindDDLGoldPurity();
            lblheadpurity.Text = "ADD GOLD PURITY";
            txtsalesrate.ReadOnly = true;

        }
        if (ddlcategory.SelectedItem.Text == "Silver")
        {
            BindDDLSilverPurity();
            lblheadpurity.Text = "ADD SILVER PURITY";
            txtsalesrate.ReadOnly = true;

        }
        if (ddlcategory.SelectedItem.Text == "Gemstones")
        {
            txtsalesrate.ReadOnly = false;
            txtsalesrate.Text = "";

            ddlpurity.Items.Clear();

        }

    }

Answer 1

將AutoPostBack =“ False”設置為擺脫刷新行為。

Answer 2

您應該將兩個控件都包裝在UpdatePanel 。

在第二部分。 去掉

AutoPostBack="true" 

從您的DropDownList 。

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel runat="server" ID="UpdatePanel" UpdateMode="Conditional">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="ddlcategory" EventName="SelectedIndexChanged" />
    </Triggers>
    <ContentTemplate>
        <asp:DropDownList ID="ddlcategory" class="form-control txtboxmargin validate[required]"
            runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlcategory_SelectedIndexChanged"
            AppendDataBoundItems="True">
            <asp:ListItem Value="">--select category--</asp:ListItem>
        </asp:DropDownList>
        <asp:DropDownList ID="ddlpurity" class="form-control txtboxmargin" AutoPostBack="True"
            runat="server" OnSelectedIndexChanged="ddlpurity_SelectedIndexChanged">
        </asp:DropDownList>
    </ContentTemplate>
</asp:UpdatePanel>

您也可以使用javascript / jquery執行數據庫請求。

見參考