Question

我正在尝试编写报价生成器。对于每种产品，都有一组选项。我想为每个选项动态添加一个下拉列表，然后将他们的SelectedIndexChanged事件全部连接起来以更新报价成本。

将DropDownList控件添加到UpdatePanel时没有任何问题，但我似乎无法连接事件。

页面加载后，下拉列表及其数据，但更改它们不会调用SelectedIndexChanged事件处理程序，QuoteUpdatePanel也不会更新。我有这样的事情：

修改：自programmatically adding AsyncPostBackTrigger controls is not supported以来，我已将我的代码更改为此内容，但我仍然没有收到此事件：

编辑2：尝试添加PlaceHolder以将下拉列表添加到（而不是直接添加到ContentTemplateContainer中，仍然没有触发事件。

QuotePanel.ASCX

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

<asp:UpdatePanel ID="QuoteUpdatePanel" runat="server" ChildrenAsTriggers="true">
    <ContentTemplate>
        Cost: <asp:Label ID="QuoteCostLabel" runat="server" />
        <fieldset id="standard-options">
            <legend>Standard Options</legend>
            <asp:UpdatePanel ID="StandardOptionsUpdatePanel" runat="server" ChildrenAsTriggers="true" UpdateMode="Conditional">
                <ContentTemplate>
                <asp:PlaceHolder ID="StandardOptionsPlaceHolder" runat="server" />                   
                </ContentTemplate>
            </asp:UpdatePanel>
        </fieldset>
    </ContentTemplate>
</asp:UpdatePanel>

添加下拉列表及其要接线的事件的代码：

protected void PopluateUpdatePanel(IEnumerable<IQuoteProperty> standardOptions)
{
    foreach (IQuoteProperty standardOp in standardOptions)
    {
        QuotePropertyDropDownList<IQuoteProperty> dropDownList = new QuotePropertyDropDownList<IQuoteProperty>(standardOp);
        dropDownList.SelectedIndexChanged += QuotePropertyDropDown_SelectedIndexChanged;
        dropDownList.ID = standardOp.GetType().Name + "DropDownList";
        dropDownList.CssClass = "quote-property-dropdownlist";

        Label propertyLabel = new Label() {Text = standardOp.Title, CssClass = "quote-property-label"};

        StandardOptionsPlaceHolder.Controls.Add(propertyLabel);
        StandardOptionsPlaceHolder.Controls.Add(dropDownList);

        _standardOptionsDropDownLists.Add(dropDownList);

        ScriptManager.RegisterAsyncPostBackControl(dropDownList);

    }

}

void QuotePropertyDropDown_SelectedIndexChanged(object sender, EventArgs e)
{
    QuoteCostLabel.Text = QuoteCost.ToString();
    StandardOptionsUpdatePanel.Update();
}

Answer 1

~~AFAIK，以编程方式向UpdatePanel控件添加异步触发器正在工作。~~

解决方法是在Page_Init事件中添加它们，并将触发器的ControlID属性设置为控件唯一ID值：

AsyncPostBackTrigger trigger = new AsyncPostBackTrigger(); // unique id instead of client id trigger.ControlID = yourDropDownControl.UniqueID; trigger.EventName = "SelectedIndexChanged"; QuoteUpdatePanel.Triggers.Add(trigger);

似乎使这项工作。我在上面创建了类似的页面/控件结构。因此，有用户控件QuotePropertyControl和Default页面可以保存此控件。

我添加了dropDownList.AutoPostBack = true属性，并且能够从下拉列表中捕获异步回发。所以，猜测问题出在这个属性中。

还有一件事：如何注册异步触发器并不重要;变体ScriptManager.RegisterAsyncPostBackControl和AsyncPostBackTrigger都像魅力一样（直到页面的init事件）。

我是这样做的：

<强> QuotePropertyControl.ascx.cs

private string[] data = { "a", "b", "c", "d", "e" };

public void PopluateUpdatePanel(IEnumerable<string> standardOptions)
{
    foreach (string standardOp in standardOptions)
    {
        DropDownList dropDownList = new DropDownList();
        dropDownList.SelectedIndexChanged +=
            QuotePropertyDropDown_SelectedIndexChanged;
        dropDownList.ID = standardOp + "DropDownList";
        dropDownList.CssClass = "quote-property-dropdownlist";
        dropDownList.AutoPostBack = true;
        dropDownList.DataSource = data;
        dropDownList.DataBind();

        Label propertyLabel = new Label() { Text = standardOp };

        StandardOptionsPlaceHolder.Controls.Add(propertyLabel);
        StandardOptionsPlaceHolder.Controls.Add(dropDownList);

        ScriptManager.GetCurrent(Page)
            .RegisterAsyncPostBackControl(dropDownList);
    }
}

protected void QuotePropertyDropDown_SelectedIndexChanged(
    object sender,
    EventArgs e
    )
{
    StandardOptionsUpdatePanel.Update();
}

<强> QuotePropertyControl.ascx

<asp:UpdatePanel ID="QuoteUpdatePanel" runat="server" ChildrenAsTriggers="true">
    <ContentTemplate>
        Cost:
        <asp:Label ID="QuoteCostLabel" runat="server" />
        <fieldset id="standard-options">
            <legend>Standard Options</legend>
            <asp:UpdatePanel ID="StandardOptionsUpdatePanel" 
                runat="server" 
                ChildrenAsTriggers="true" 
                UpdateMode="Conditional">
                <ContentTemplate>
                    <asp:PlaceHolder ID="StandardOptionsPlaceHolder" 
                    runat="server" />
                </ContentTemplate>
            </asp:UpdatePanel>
        </fieldset>
    </ContentTemplate>
</asp:UpdatePanel>

<强> Default.aspx.cs

string[] names = { "ab", "bc", "ef" };

protected void Page_Init(object sender, EventArgs e)
{
    ctlQuoteProperty.PopluateUpdatePanel(names);
}

<强> Default.aspx的

<%@ Register Src="~/QuotePropertyControl.ascx" 
             TagPrefix="uc" 
             TagName="QuoteProperty" %>

<form id="form1" runat="server">
<div>
    <asp:ScriptManager ID="ScriptManager" runat="server" />
    <uc:QuoteProperty runat="server"
        ID="ctlQuoteProperty">
    </uc:QuoteProperty>
</div>
</form>

如何以编程方式将触发器添加到ASP.NET UpdatePanel？

1 个答案: