c# - ASP.NET - Javascript timeOut Warning based on sessionState timeOut in web.config

Question

Problem: I am looking to create a time-out warning message on an asp.net page with a c# code behind based off my webconfig sessionState TimeOut Attribute.

Code on web.config:

<configuration>
    <system.web>
        <sessionState timeout="20"></sessionState>
    </system.web>
</configuration>
<system.serviceModel>
    <bindings>
        <basicHttpBinding>
            <binding name="EchoSignDocumentService10HttpBinding" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="6553600" maxBufferPoolSize="524288" maxReceivedMessageSize="6553600" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true">
                <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="1638400" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                <security mode="Transport">
                    <transport clientCredentialType="None" proxyCredentialType="None" realm="" />
                    <message clientCredentialType="UserName" algorithmSuite="Default" />
                </security>
            </binding>
            <binding name="EchoSignDocumentService10HttpBinding1" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true">
                <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                <security mode="None">
                    <transport clientCredentialType="None" proxyCredentialType="None" realm="" />
                    <message clientCredentialType="UserName" algorithmSuite="Default" />
                </security>
            </binding>
        </basicHttpBinding>
    </bindings>
</system.serviceModel>

Answer 1

Pseudo code:

• Read the timeout setting in codebehind
• Register a ClientScriptblock (setTimeout passing the timeout period (20 * 60))
• On timeout, display a warning label on the page

Sample code:

    public void RegisterTimeoutWarning(System.Web.UI.Page Page)
    {
        var timeout = HttpContext.Current.Session.Timeout * 60 * 1000;
        Page.ClientScript.RegisterStartupScript(Page.GetType(), 
                "timeoutWarning", 
                string.Format("setTimeout(function () {{ alert('Session about to expire'); }}, {0});", timeout), true);
    }

Of course, you can improve the client side display (rather than showing an alert) by displaying warning popups or even a confirm popup which you can then use to renew the session.