LINQ & Entity Framework : issue with concatenating NULL value
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I have an INT fields called TradeNo that may contain NULL value. The requirement is to display on the dropdown the "contract Id" and the "trade no" in bracket and if "trade no" is null, then display N/A.

    Example:
    44444 (2222)
    55555 ( N/A )

Here’s what I thought would work. This is my functions that returns a SelectList

    public IEnumerable<SelectListItem> GetContractsBySupplierDropDown(string supplier)
        {
            
            var result = from c in context.Contracts 
                         where c.Supplier==supplier 
                         orderby c.ContractID
                         select new { Text = c.ContractID.ToString() + " (" + (c.TradeNo.HasValue  ? c.TradeNo.Value.ToString() : " N/A ").ToString() + " )"  , Value = c.ContractID };

            return new SelectList(result, "Text", "Value"); 
        }

The error being return is:

    LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method      cannot be translated into a store expression.

From what I can tell, the error displayed means that EF is trying to convert ToString to a database function?