ASP.NET 4.5 provides support for improved state management features. The ViewStateMode property gives you better control over ViewState. Note that this property can have one of three values: Enabled, Disabled, or Inherit. You have another new property introduced, named ClientIDMode. You can use this property to set the ClientID for server controls and use it from the client side. This property can have one of four values: Static, Predictable, Legacy, or Inherit.

The following script code illustrates how you can display the ClientID for a control using JavaScript:

<script type="text/javascript">
function DisplayClientID() 
{
   alert('<%= myButtonControl.ClientID %>'),
}
</script>

Here's an example that shows how you can use the ClientIDMode property:

<asp:Panel ID="pnlFirst" runat="server" ClientIDMode="Static">

The following code snippet illustrates how the Predictable mode is used:

<asp:Content ID="contentObj" ContentPlaceHolderID="contentPlaceHolderObject" Runat="server">
    <asp:Panel ID="ParentPanel" runat="server" ClientIDMode="Static">          
        <asp:Panel ID="ChildPanel" runat="server" ClientIDMode="Predictable">          
            <asp:Button ID="btnSubmit" runat="server"/>          
        </asp:Panel>
    </asp:Panel>
</asp:Content>

If ClientIDMode for a control is set to Inherit, the control inherits the ClientIDMode setting of its parent control. Here is an example:

<asp:Content ID="contentObj" ContentPlaceHolderID="contentPlaceHolderObj"
Runat="Server">
    <asp:Panel ID="PanelParent" runat="server">          
        <asp:Panel ID="PanelChild" runat="server" ClientIDMode="Static">          
            <asp:Button ID="btnSubmit" runat="server" ClientIDMode="Inherit" />          
        </asp:Panel>
    </asp:Panel>
</asp:Content>

ASP.NET 4.5 enables you to monitor resource utilization. To enable this resource monitoring, all you need to do is to use the following configuration in the aspnet.config file:

<configuration>
<runtime>
<appDomainResourceMonitoring enabled="true"/>
</runtime>
</configuration>

With ASP.NET 4.x, Output Caching has improved a lot. Output Caching is a feature that enables you to store the output of your ASP.NET web pages in cache memory so that subsequent requests to the same web page can be fetched from the memory cache. By doing this, the application's performance can be improved to a great extent for web pages that contain relatively stale data.

With ASP.NET 4.x, you have a feature named Extensible Output Caching that you can use to add extensibility points to Output Caching. You can now also manage and configure one or more custom Output Cache providers. Here are the Cache Storages for which the ASP.NET 4.x Cache API provides support:

To configure your custom Output Cache provider, all you need to do is to specify the following in the application's web.config file:

<caching>
<outputCache defaultProvider="Packt.CustomCacheProvider">
<providers>
<add name="DiskCache"
type="Packt.CustomCacheProvider, Packt"/>
</providers>
</outputCache>
</caching>

ASP.NET 4.x provides support for SEO. The System.Web.Routing namespace provides support for routing through the usage of the RouteTable and the PageRouteHandler classes. You can also achieve SEO using the Page Meta Keyword and Description features available in ASP.NET 4.5, as given in the following code snippet:

protected void Page_Load(object sender, EventArgs e)
{
    this.Page.Title = "Packt";
    this.Page.MetaKeywords = "Books";
    this.Page.MetaDescription = "Packt Books";
}

In this section, we will highlight some other notable enhancements in ASP.NET 4.5: