Documentation for: ASP.NET Ajax Version 1.0

This documentation is for a previous version. For the current released version, see the ASP.NET Ajax documentation on MSDN.

 

 

 

 

 

 

 

Interval Property

Gets or sets the number of milliseconds to wait before initiating a postback.

Syntax

CSharp

[DefaultValueAttribute()]
[CategoryAttribute("Behavior")]
public int Interval { get; set; }

VisualBasic

<DefaultValueAttribute()> _
<CategoryAttribute("Behavior")> _
Public Property Interval As Integer

ManagedCPlusPlus

[DefaultValueAttribute()]
[CategoryAttribute(L"Behavior")]
public:
int Interval {
	int get ();
	void set (int value);
}

JSharp

/** @property */
/** @property */

Value

Return Value

The number of milliseconds to wait before initiating a postback. The default value is 60,000 (60 seconds).

Remarks

Use the Interval property to set how often the Timer control initiates a postback to the server. You can change the value of the Interval property in server code after a postback, such as in an event handler for the Tick event. The accuracy of when the Timer control posts back to the Web server depends on the accuracy of the ECMAScript (JavaScript) window.setTimeout() function that is running in the browser.

note

Setting the Interval property to a small value can generate significant traffic to and from the Web server. Use the Timer control to refresh the content only as often as necessary.

When you change the value of the Interval property, the ECMAScript timing code running in the browser will be reset when the updates are rendered.

Examples

The following example shows an UpdatePanel control that displays a randomly generated stock price and the time that the stock price was generated. By default, the Timer control updates the content in the UpdatePanel control every 10 seconds. The user can decide to update the stock price every 10 seconds, every 60 seconds, or not at all. The Interval property is set to the user's choice.

cs

<%@ Page Language="C#" AutoEventWireup="true" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>Timer Example Page</title>
    <script runat="server">
        protected void Page_Load(object sender, EventArgs e)
        {
            OriginalTime.Text = DateTime.Now.ToLongTimeString();
        }

        protected void Timer1_Tick(object sender, EventArgs e)
        {
            StockPrice.Text = GetStockPrice();
            TimeOfPrice.Text = DateTime.Now.ToLongTimeString();
        }

        private string GetStockPrice()
        {
            double randomStockPrice = 50 + new Random().NextDouble();
            return randomStockPrice.ToString("C");
        }

        protected void RadioButton1_CheckedChanged(object sender, EventArgs e)
        {
            Timer1.Enabled = true;
            Timer1.Interval = 10000;
        }

        protected void RadioButton2_CheckedChanged(object sender, EventArgs e)
        {
            Timer1.Enabled = true;
            Timer1.Interval = 60000;
        }

        protected void RadioButton3_CheckedChanged(object sender, EventArgs e)
        {
            Timer1.Enabled = false;
        }

</script>
</head>
<body>
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server" />
        <asp:Timer ID="Timer1" OnTick="Timer1_Tick" runat="server" Interval="10000" />

        <asp:UpdatePanel ID="StockPricePanel" runat="server" UpdateMode="Conditional">
        <Triggers>
            <asp:AsyncPostBackTrigger ControlID="Timer1" />
        </Triggers>
        <ContentTemplate>
            Stock price is <asp:Label id="StockPrice" runat="server"></asp:Label><BR />
            as of <asp:Label id="TimeOfPrice" runat="server"></asp:Label>  
            <br />

        </ContentTemplate>
        </asp:UpdatePanel>
        <div>
        <br />
        Update stock price every:<br />
        <asp:RadioButton ID="RadioButton1" AutoPostBack="true" GroupName="TimerFrequency" runat="server" Text="10 seconds" OnCheckedChanged="RadioButton1_CheckedChanged" /><br />
        <asp:RadioButton ID="RadioButton2" AutoPostBack="true" GroupName="TimerFrequency" runat="server" Text="60 seconds" OnCheckedChanged="RadioButton2_CheckedChanged" /><br />
        <asp:RadioButton ID="RadioButton3" AutoPostBack="true" GroupName="TimerFrequency" runat="server" Text="Never" OnCheckedChanged="RadioButton3_CheckedChanged" />
        <br />
        Page loaded at <asp:Label ID="OriginalTime" runat="server"></asp:Label>
        </div>
    </form>
</body>
</html>

vb

<%@ Page Language="VB" AutoEventWireup="true" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Timer Example Page</title>
    <script runat="server">
        Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
            OriginalTime.Text = DateTime.Now.ToLongTimeString()
        End Sub

        Protected Sub Timer1_Tick(ByVal sender As Object, ByVal e As EventArgs)
            StockPrice.Text = GetStockPrice()
            TimeOfPrice.Text = DateTime.Now.ToLongTimeString()
        End Sub

        Private Function GetStockPrice() As String
            Dim randomStockPrice As Double = 50 + New Random().NextDouble()
            Return randomStockPrice.ToString("C")
        End Function

        Protected Sub RadioButton1_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
            Timer1.Interval = 10000
            Timer1.Enabled = True
        End Sub

        Protected Sub RadioButton2_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
            Timer1.Interval = 60000
            Timer1.Enabled = True
        End Sub

        Protected Sub RadioButton3_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
            Timer1.Enabled = False
        End Sub
</script>
</head>
<body>
    <form id="form1" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server" />
        <asp:Timer ID="Timer1" OnTick="Timer1_Tick" runat="server" Interval="10000" />

        <asp:UpdatePanel ID="StockPricePanel" runat="server" UpdateMode="Conditional">
        <Triggers>
            <asp:AsyncPostBackTrigger ControlID="Timer1" />
        </Triggers>
        <ContentTemplate>
            Stock price is <asp:Label id="StockPrice" runat="server"></asp:Label><BR />
            as of <asp:Label id="TimeOfPrice" runat="server"></asp:Label>  
        </ContentTemplate>
        </asp:UpdatePanel>
        <div>
            <asp:RadioButton ID="RadioButton1" AutoPostBack="true" GroupName="TimerFrequency" runat="server" Text="10 seconds" OnCheckedChanged="RadioButton1_CheckedChanged" /><br />
            <asp:RadioButton ID="RadioButton2" AutoPostBack="true" GroupName="TimerFrequency" runat="server" Text="60 seconds" OnCheckedChanged="RadioButton2_CheckedChanged" /><br />
            <asp:RadioButton ID="RadioButton3" AutoPostBack="true" GroupName="TimerFrequency" runat="server" Text="Never" OnCheckedChanged="RadioButton3_CheckedChanged" /><br />
            <br />
        Page originally created at <asp:Label ID="OriginalTime" runat="server"></asp:Label>
        </div>
    </form>
</body>
</html>

Assembly: System.Web.Extensions (Module: System.Web.Extensions)