Programming ASP.NET, 3rd Edition

Data Types

ASP.NET web services can use any CLR-supported primitive data type as a parameter or a return value. Table 15-2 summarizes the valid types.

Table 15-2. CLR-supported primitive data types

Type	Description
byte	1-byte unsigned integer
short	2-byte signed integer
int	4-byte signed integer
long	8-byte signed integer
float	4-byte floating point
double	8-byte floating point
decimal	16-byte floating point
bool	True/false
char	Single Unicode character
string	Sequence of Unicode characters
DateTime	Represents dates and times
object	Any type

In addition to the primitive data types, you can use arrays and ArrayLists of the primitive types. Since data is passed between a web service and its clients using XML, whatever is used as either a parameter or return value must be represented in an XML schema or XSD.

Arrays

The examples shown so far in this chapter have used simple primitive types, such as strings and numbers, as parameters and return values. You can also use an array of primitive types as in the code shown here:

    [WebMethod]
    public string[] GetArray()
    {
       string[] TestArray = {"a","b","c"};
       return TestArray;
    }

The main limitation of using arrays, of course, is that you must know the number of elements at design time. If the number of elements is dynamic, then an ArrayList will be called for. If an ArrayList is used in the web service, it will be converted to an object array when the web service description is created. The client ...