How to add a System.Xml.XmlDocument type to applications state

I am using Asp.net 3.5 and C#

I have to add an XmlDocument to my application state so that everytime my application doesnt access the XML file on my filesystem, I will add this at the Application_Start() function in Global.asax.cs

I am adding this to system state as :

protected void Application_Start(Object sender, EventArgs e)
{    
    string filePath = Server.MapPath("<path to my XML FILE>");
    XmlDocument xmlDoc = new XmlDocument();
    try
    {
        xmlTickerDoc.Load(filePath);
    }
    finally
    {
        HttpContext.Current.Application["xmlDoc"] = xmlDoc;
    }
}

In this code i try to load the xml file and if the file is not loaded due to any problem then i am wanting a null XmlDocument.

I access this XmlDocument as :

XmlDocument xmlDoc = new XmlDocument();
xmlDoc = HttpContext.Current.Application["xmlDoc"];

the 开发者_运维百科error i get while build is

Cannot implicitly convert type 'object' to 'System.Xml.XmlDocument'. An explicit conversion exists

So How to assign the HttpContext.Current.Application["xmlDoc"] variable as System.Xml.XmlDocument ?

Your problem is here:

xmlDoc = HttpContext.Current.Application["xmlDoc"];

Try

xmlDoc = HttpContext.Current.Application["xmlDoc"] as System.Xml.XmlDocument; 

Got the answer after a little googling, a simple one but can be tricky for a PHP developer working on C# (as it was in my case) well i just had to explicitly cast my application state variable to XmlDocument that is at place of :

XmlDocument xmlDoc = new XmlDocument();
xmlDoc = HttpContext.Current.Application["xmlDoc"];

I used :

XmlDocument xmlDoc = new XmlDocument();
xmlDoc = (XmlDocument) HttpContext.Current.Application["xmlDoc"];

and it becomes Robust :)

can any one tell me what will be the lifetime of this ApplicationState Variable ?