Hi I am writing this method but get an error that says "Specified cast is not valid. " in the "Books books = new Books((string)reader[0], (string)reader[1]," line. Anyone pls suggests me.

public List<Books> GetBooks()
        {
            List<Books> bookList = new List<Books>();
            SqlConnection myConnection = new SqlConnection(connectionString);
            SqlCommand myCommand = new SqlCommand("SPGetAllBooks", myConnection);
            myConnection.Open();
            SqlDataReader reader = myCommand.ExecuteReader();
            while (reader.Read())
            {
                Books books = new Books((string)reader[0], (string)reader[1],
                    (string)reader[2], (string)reader[3], (int)reader[4]
                    ,(double)reader[5], (int)reader[6], (int)reader[7]
                    ,(string)reader);
                bookList.Add(books);
            }
            myConnection.Close();
            reader.Close();
            myCommand.Dispose();
            if (bookList != null && bookList.Count > 0)
                return bookList;
            else return null;
        }

The following is my constructor in Books class :
  public Books(string bookID, string title, string authorFirstname
            , string authorLastname, int edition, double price,
            int discount, int amount, string category)

I dont think, that you have to cast the outpur of the reader object. You can simply type
Books books = new Books(reader[0], reader[1], reader[2],
                        reader[3], reader[4], reader[5],
                        reader[6], reader[7],reader);

Just try, it will work

-Pallav

I tried that then I got this message instead.

Argument '1': cannot convert from 'object' to 'string'

You needn't worry too much over the string casts but the others may not work. What data types are declared in the database for the fields returned in the reader?

--

Joe (Microsoft MVP - XML)

Yes, That is the point. In my DB I set the type of Price column to money. But I created Price in Books class as Double as following:
        public Books(string bookID, string title, string authorFirstname
            , string authorLastname, int edition, double price,
            int discount, int amount, string category)...
next, tried to cast this "(double)reader[5]".....what do u think could be the possible solution?

You need to cast every variable from the datareader to the appropriate type (unless the type is 'Object').

So for this constructor signature:

    public Books(string bookID, string title, string authorFirstname
            , string authorLastname, int edition, double price,
            int discount, int amount, string category)

you will at least need something like this:

Books books = new Books(reader[0].ToString(), reader[1].ToString(), reader[2].ToString(),
                        reader[3].ToString(), (int)reader[4], (double)reader[5],
                        (int)reader[6], (int)reader[7], reader.ToString());

-Peter