Question

I am trying to assign null to the variable IdSubCategory if the session variable Session["SubCategory"] is null

Why does the following not work?

decimal tmpvalue2;
decimal? IdSubCategory = null;    
if (decimal.TryParse((string)Session["SubCategory"], out tmpvalue2))
    IdSubCategory = tmpvalue2;

Answer 1

I usually wrap my session variables in a property.

    protected decimal? IdSubCategory
    {
        get
        {
            if (Session["SubCategory"] == null)
                return null;
            else
                return decimal.Parse(Session["SubCategory"].ToString());
        }
        set
        {
            Session["SubCategory"] = value;
        }
    }