Question

我的Checkbox_OnCheckedChanged和Dropdownlist_OnSelectedIndexChanged事件都没有触发我的代码中的相关功能。

两个控件都绑定到GridView中的值。在从UI中引发的第一个OnCheckedChanged或OnSelectedIndexChanged事件中，代码中的函数会在没有错误的情况下触发，但是如果我刷新UpdatePanel，例如通过更改数据的日期范围在GridView内，因此加载更多或更少的记录，不再调用OnCheckedChanged和OnSelectedIndexChanged函数，但会发生PostBack。

我相信这些函数没有被调用，而是调用重新绑定GridView的函数：

 private void report_DateChanged(object sender, EventArgs e)
 {
        // Bind GridView here..
 }

然而，我无法弄清楚为什么会发生这种情况。

我有一个MasterPage：

namespace ReportingSystemV2.Reporting
{
public partial class Reporting : System.Web.UI.MasterPage
{
    protected void Page_Load(object sender, EventArgs e)
    {
        // Attach to DateChanged Event on DateChange UserControl to Function
        DateRangeSelect.dateChanged += new DateRangeSelect.dateChangedEventHandler(dtRgSel_dateChanged);
    }

    // Declare an event for the content pages
    public event EventHandler reportDateChanged;

    // Called on a date change event
    protected void dtRgSel_dateChanged(object sender, DateChangedEventArgs e)
    {
        // Raise the event for content pages
        if (reportDateChanged != null)
            reportDateChanged(this, EventArgs.Empty);
    }
}

此MasterPage有一个Control用于选择我的日期范围..

我的控件ascx代码的主要代码部分是：

<%--UpdatePanel to trigger datechange--%>
<asp:UpdatePanel runat="server" ID="UpdatePanelDateChanged" OnLoad="UpdatePanelDateChanged_Load" >
</asp:UpdatePanel>

<%--When the date changes in javascript a postback is called in the updatepanel--%>
__doPostBack('<%=UpdatePanelDateChanged.ClientID %>', null);

此控件的代码主要部分是：

// Declare a delegate
public delegate void dateChangedEventHandler(object sender, DateChangedEventArgs e);

// Declare an event for any pages that have the control
public event dateChangedEventHandler dateChanged;

protected virtual void OnDateChanged(DateChangedEventArgs e)
{
    dateChangedEventHandler handler = dateChanged;

    // Raise the event
    if (handler != null)
        handler(this, e);
}

protected void UpdatePanelDateChanged_Load(object sender, EventArgs e)
{
   // Trigger the controls public event
   OnDateChanged(new DateChangedEventArgs(DateTime.Parse(dates[0]), DateTime.Parse(dates[1])));

}

在我的内容页面中，我的aspx代码为：

<%@ Page Title="Downtime" Language="C#" MasterPageFile="~/Reporting/Reporting.Master" AutoEventWireup="true" CodeBehind="GensetDowntime.aspx.cs" Inherits="ReportingSystemV2.Reporting.GensetDowntime" %>

<%@ MasterType VirtualPath="~/Reporting/Reporting.Master" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ReportingSubContent" runat="server">
<div class="container-fluid">
    <asp:UpdatePanel ID="updPanelDowntime" runat="server">
        <ContentTemplate>
            <div class="row">
                <div id="downtimeDiv" runat="server">
                    <asp:GridView ID="gridDowntime" runat="server" AutoGenerateColumns="False" GridLines="None" CssClass="table table-striped table-condensed"
                        OnRowDataBound="gridDowntime_RowDataBound"
                        OnSelectedIndexChanged="gridDowntime_SelectedIndexChanged"
                        DataKeyNames="ID,ID_Location,iddown,idup,dtdown,dtup,isexempt" EmptyDataText="No exempts in the selected period.">
                        <Columns>
                            <asp:TemplateField>
                                <ItemTemplate>
                            <asp:TemplateField HeaderText="Exempt?">
                                <ItemTemplate>
                                    <asp:DropDownList ID="ddlDowntimeExempt" AutoPostBack="true" runat="server"
                                        OnSelectedIndexChanged="ddlDowntimeExempt_SelectedIndexChanged">
                                        <asp:ListItem Value="-1">Unverified</asp:ListItem>
                                        <asp:ListItem Value="1">Yes</asp:ListItem>
                                        <asp:ListItem Value="0">No</asp:ListItem>
                                    </asp:DropDownList>
                                    <asp:Label ID="lblDowntimeExempt" runat="server" Text='<%#DataBinder.Eval(Container.DataItem,"isexempt")%>' Visible="false"></asp:Label>
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="Exclude?">
                                <ItemTemplate>
                                    <asp:CheckBox ID="chkDowntimeExclude" runat="server" Checked='<%#Convert.ToBoolean(Eval("ISEXCLUDED")) %>' OnCheckedChanged="chkDowntimeExclude_CheckedChanged" AutoPostBack="true"/>
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:CommandField ShowSelectButton="True" SelectText="Details" />
                        </Columns>

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

最后我的内容页面的代码是：

    protected void Page_PreInit(object sender, EventArgs e)
    {
        // Attach to UserControl Event on the MasterPage
        Master.reportDateChanged += new EventHandler(report_DateChanged);
    }

    // If the user changes the date lets update the table
    private void report_DateChanged(object sender, EventArgs e)
    {
        // Bind the gridview
    }

    // Function to be called when the ddl selectedindex is changed, only called on initial page load
    protected void ddlDowntimeExempt_SelectedIndexChanged(object sender, EventArgs e)
    {
        // Applies the values selected in the exempt DDL to the database value
    }

    // function to be called when the checkbox checked state is change, again only called on the initial page loading - not after a postback
    protected void chkDowntimeExclude_CheckedChanged(object sender, EventArgs e)
    {
        // When the Exclude checkbox is changed, update the Db
    }

上面的代码显示control使用j trigger PostBack UpdatePanel triggers Control MasterPage中的公共事件}}。 Control具有附加到MasterPage事件的函数，此ContentPage函数会更新一些值并触发可以访问ContentPage的新事件。 MasterPage为此DateRange事件附加了一个函数，当GridView更改时，它将加载import unittest from foobar import MyException import foobar as fb class FooBarTestCases(unittest.TestCase): def test_bar(self): with self.assertRaises(ValueError): fb.FooBar().bar() def test_foo(self): with self.assertRaises(MyException): fb.FooBar().foo() if __name__ == '__main__': unittest.main()的数据并绑定它。

Answer 1

母版页在“子”页面的控件开头附加额外的名称。很可能你会期望下拉列表中有一个名称，但它会有一个不同的更长的名称，如ctrl1 $ something $ dropdown。

使用Chrome中的inspect或dev工具检查ida，确认这是您的问题。

Answer 2

我认为你错过了异步回发触发器。当更新面板部分回发时，它会发送回整个页面，进行处理，然后仅返回更改的部分。可能在这个过程中，发生了轻微的ID更改，然后错过了注册。 report_DateChanged很可能被解雇，因为它是页面上第一个实现IPostBackEventHandler的控件（因为复选框和下拉列表上的回发不再起作用）

要解决这个问题，请将应该执行异步回发的每个控件显式添加到更新面板的触发器中。像这样：

protected void gridDowntime_RowDataBound(object sender, GridViewRowEventArgs e)  
{  
    DropDownList ddl = e.Row.FindControl("ddlDowntimeExempt") as DropDownList;  
    CheckBox cb = e.Row.FindControl("chkDowntimeExclude") as CheckBox;  
    ScriptManager.GetCurrent(this).RegisterAsyncPostBackControl(ddl);  
    ScriptManager.GetCurrent(this).RegisterAsyncPostBackControl(cb);  
}

Answer 3

问题已解决，通过修改DateRangeControl中的代码，UpdatePanel上的PostBacks不再被__doPostBack('<%=UpdatePanelDateChanged.ClientID %>', null);触发，只有Javascript中的protected void UpdatePanelDateChanged_Load(object sender, EventArgs e) { if (Request["__EVENTTARGET"] == UpdatePanelDateChanged.ClientID) { //Trigger Event OnDateChanged(new DateChangedEventArgs(DateTime.Parse(dates[0]), DateTime.Parse(dates[1]))); } }被调用了http://encosia.com/are-you-making-these-3-common-aspnet-ajax-mistakes/。

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C＃ASP.NET CheckBox_OnCheckedChanged未按预期触发

3 个答案: