An exception of type System.Data.Entity.Validation.DbEntityValidationException occurred in EntityFramework.dll but was not handled in user code

An exception of type 'System.Data.Entity.Validation.DbEntityValidationException' occurred in EntityFramework.dll but was not handled in user code

While running the application, I got this exception for the following code.

InvoiceDetail invoicedetail = new InvoiceDetail()
            {
                ItemId = int.Parse(Request.Form["ItemId"]),
                Quantity = int.Parse(Request.Form["Quantity"]),
                SchemeDiscount = decimal.Parse(Request.Form["SchemeDiscount"]),
                StockDiscount = decimal.Parse(Request.Form["StockDiscount"])
            }; 

I got this error while filling the object values. Then, I set a breakpoint for where an exception is thrown, and use it to inspect the problem. I identified, it was due to that one of the value went undefined. Afterwards I sent proper value it works fine. We must check each and every value of the inputs.