Why Convert.ToDecimal returns different values

Question

I was hoping someone could help me understand why Convert.ToDecimal when used in linq rounds a decimal number, and when used externally, it doesn't

Given the following DB:

CREATE TABLE [dbo].[Widgets]( [ID] [int] NOT NULL, [WidgetName] [varchar](50) NOT NULL, [UnitsAvailable] [int] NOT NULL, [WeightInGrams] [decimal](10, 6) NULL ) ON [PRIMARY] GO INSERT [dbo].[Widgets] VALUES (1, N'Best thing ever', 100, CAST(10.000210 AS Decimal(10, 6))) INSERT [dbo].[Widgets] VALUES (2, N'Next Best thing', 50, CAST(100.000151 AS Decimal(10, 6))) INSERT [dbo].[Widgets] VALUES (3, N'The Other Model', 25, CAST(5.231651 AS Decimal(10, 6))) 

CODE:

 class Program { static void Main(string[] args) { Console.WriteLine("------Example 1--------"); LqToSqlDataContext _ctx = new LqToSqlDataContext(); List<Widget> inventory = (from c in _ctx.linqWidgets select new Widget() { Id = c.ID, Name = c.WidgetName, UnitsOnHand = c.UnitsAvailable, WeightInGrams = Convert.ToDecimal(c.WeightInGrams) }).ToList(); foreach(Widget w in inventory) { Console.WriteLine(w.ToString()); } Console.WriteLine("------Example 2--------"); var _linqInventory = _ctx.linqWidgets; Widget temp = null; foreach(linqWidget lw in _linqInventory) { temp = new Widget(); temp.Id = lw.ID; temp.Name = lw.WidgetName; temp.UnitsOnHand = lw.UnitsAvailable; temp.WeightInGrams = Convert.ToDecimal(lw.WeightInGrams); Console.WriteLine(temp.ToString()); } Console.ReadLine(); } } class Widget { public int Id { get; set; } public string Name { get; set; } public int UnitsOnHand { get; set; } public decimal WeightInGrams { get; set; } public override string ToString() { return this.Id + "\t" + this.Name + "\t" + this.UnitsOnHand + "\t" + this.WeightInGrams; } } 

Output

 ------Example 1-------- 1 Best thing ever 100 10.0002 2 Next Best thing 50 100.0002 3 The Other Model 25 5.2317 ------Example 2-------- 1 Best thing ever 100 10.000210 2 Next Best thing 50 100.000151 3 The Other Model 25 5.231651 

Answer 1

Because LinqtoSql translates Convert.ToDecimal into a sql statement such as CONVERT (DECIMAL ({someNumberLinqComesupWith}, 4)

Answer 2

Since the C # decimal type does not match the decimal type in the database.

As you can see, C # decimal more accurate.