I have an final year project based on Web based in C# ASP.net when i run it, it will show the error

Question

Protected void Page_PreInit(object sender,Event args e)
{
this.Theme=Session["Theme name"].ToString();
} 

null exception error was unhandle by user code

Answer 1

Looks like the value of:

Session["Theme name"]

is NULL.

You should test this before the line. Something like:

protected void Page_PreInit(object sender,Event args e) 
{ 
if(Session["Theme name"] != null)
{
this.Theme=Session["Theme name"].ToString(); 
}
else
{
//use the default theme
}

}

Answer 2

Check this

c# how to set up and use session state from preinit

Answer 3

i think your session "Session["Theme name"]" not contains any theme name. i think your session is returning null so before setting value to page.theme first check for existence of value in session