How to build basic web service with ASP.NET in C# – step 1

Each web service begins as a stateless class with one or more methods that the remote clients call to invoke your code.

BookService is designed to allow remote clients to retrieve information about books provided by the store. The class provides GetBooks() method that returns a DataSet with the full set of books information. It also provides a GetBooksCount() method, which simply return the number of books in the database. In this case you need some basic ADO.NET code to provide these methods.

 

public class BooksService

{

private string connectionString;

public BooksService ()

{

string connectionString =

WebConfigurationManager.ConnectionStrings[“BookStore”].ConnectionString;

}

public int GetBooksCount()

{

SqlConnection con = new SqlConnection(connectionString);

string sql = “SELECT COUNT(*) FROM Books”;

SqlCommand cmd = new SqlCommand(sql, con);

// Open the connection and get the value.

con.Open();

int numBooks = -1;

try

{

numBooks = (int)cmd.ExecuteScalar();

}

finally

{

con.Close();

}

return numBooks;

}

public DataSet GetBooks()

{

// Create the command and the connection.

string sql = “SELECT ISBN, AuthorLName, AuthorFName, Title, ” +

“Pages, Price  FROM Books”;

SqlConnection con = new SqlConnection(connectionString);

SqlDataAdapter da = new SqlDataAdapter(sql, con);

DataSet ds = new DataSet();

// Fill the DataSet.

da.Fill(ds, “Books”);

return ds;

}

}

You can use GetBooks() and GetBooksCount() in any web page in the same project, because both methods are public.