Question

我正在尝试在asp.net中创建一个计时器

Public Class _Default
Inherits System.Web.UI.Page
Dim min As Integer
Dim sec As Integer
Dim hr As Integer
Dim totalTime As Integer
Dim timerStr As String

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    totalTime = 5340
    hr = Math.Floor(totalTime / 3600)
    min = 30
    sec = totalTime Mod 60
    timerStr = String.Format("{0:00}:{1:00}:{2:00}", hr, min, sec)
    label1.Text = timerStr
End Sub


Protected Sub Timer1_Tick(ByVal sender As Object, ByVal e As EventArgs)
    Display()
    label1.Text = timerStr
End Sub
Protected Sub Display()
    totalTime -= 1
    hr = Math.Floor(totalTime / 3600)
    sec = totalTime Mod 60
    If sec = 0 Then
        min = (totalTime / 60) Mod 60
    End If
    timerStr = String.Format("{0:00}:{1:00}:{2:00}", hr, min, sec)
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
    Display()
    label1.Text = timerStr
End Sub
End Class

//更新面板代码

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:Timer ID="Timer1" runat="server" Interval="1000" OnTick="Timer1_Tick">
</asp:Timer>
<asp:Button ID="Button1" runat="server" Text="Button" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional" 
    RenderMode="Inline">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" />
    </Triggers>
     <ContentTemplate>
        <asp:Label ID="label1" runat="server"></asp:Label> 
    </ContentTemplate>
</asp:UpdatePanel>

现在根据代码定时器调用每秒但它没有发生我尝试相同的按钮和单击事件但仍然文本不更新但页面刷新当我按下按钮。我做错了什么？

Answer 1

如果您正在为网页开发计时器 - 您必须使用JavaScript在客户端进行，因为一旦服务器端代码运行并且页面呈现给浏览器 - 服务器端代码完成，否则更长时间参与页面生活。

以下是客户端计时器的简化示例。它有一个标签（在浏览器中变为SPAN）和2个按钮 - 用于启动和停止计时器：

<span id="Label1" >Seconds: 0</span>

<button id="Button1" onclick="startResetTimer()">Start/Reset</button>
<button id="Button2" onclick="stopTimer()" disabled="disabled">Stop</button>

这是负责计时器的JavaScript代码：

var time; 
var interval;

function startResetTimer() {

    document.getElementById('Button1').disabled = "disabled";
    document.getElementById('Button2').disabled = "";

    time = 0;
    interval = setInterval(function() {
        time++;
        document.getElementById('Label1').innerHTML = "Seconds: " + time
    }, 1000)
}

function stopTimer() {

    document.getElementById('Button1').disabled = "";
    document.getElementById('Button2').disabled = "disabled";

    clearInterval(interval)
}

单击“开始/重置”按钮时 - 通过setInterval功能启动计时器。当您单击“停止”时，计时器将通过clearInterval功能停止。

您可以尝试一个有效的演示here，它只显示秒数，但您应该明白这一点。

asp.net中的Timer和UpdatePanel

1 个答案: