Field Type Variables - C# Application Dataset

Question

Say I have this string variable containing a value from an SQL query stored in a variable like so:

string strDesc = ds.Tables[0].Rows[0]["Description"].ToString();

and as its a string it works ok

what about if I had field types in a database that where of type int and money, how would I apply it like above? Would it be somthing like below with a conversion applied?:

int field I want to keep it as an int

int strOrderID = ds.Tables[0].Rows[0]["OrderID"];

money field I want to keep as type money

decimal strPrice = ds.Tables[0].Rows[0]["Price"];

Thanks in advance for any answers provided

Answer 1

I suggest to use the strongly typed Field extension method which also supports nullable types:

int orderID = ds.Tables[0].Rows[0].Field<int>("OrderID");
decimal price = ds.Tables[0].Rows[0].Field<decimal>("Price");

Assuming that Price can be NULL, you can cast it to a Nullable<decimal> easily:

decimal? price = ds.Tables[0].Rows[0].Field<decimal?>("Price"); 
if(price.HasValue) Console.WriteLine(price.Value);

By the way, the old way would be simple casting:

int orderID = (int) ds.Tables[0].Rows[0]["OrderID"];

However, if you use this query more than once and you're selecting a single table or at least fields that belong together, you should consider to create a class with these properties. Then your code becomes much more readable, reusuable and maintainable.

public class Order
{
    public int OrderID { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }

    public override bool Equals(object obj)
    {
        Order o2 = obj as Order;
        if (o2 == null) return false;
        return OrderID == o2.OrderID;
    }
    public override int GetHashCode()
    {
        return OrderID;
    }
    public override string ToString()
    {
        return Description;
    }
}