Show SQL Server table content in C# console app

Question

I am trying to show some content from my SQL Server database in my C# console app.

So far I have this class :

public SqlConnection connection()
{
    SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
    builder.DataSource = "DESKTOP-UPVVOJP";
    builder.InitialCatalog = "Lagersystem";
    builder.IntegratedSecurity = true;

    return new SqlConnection(builder.ToString());
}

Product model class :

public class Product
{
    public int ProductID { get; set; }
    public string ProductName { get; set; }
    public int ProductStock { get; set; }
    public int ProductCategoryID { get; set; }
    public int ProductEmployeeID { get; set; }
    public DateTime ProductCreatedDate { get; set; }

    // Constructor
    public Product(string productname, int productstock, int productcategoryid, int productemployeeid)
    {
        ProductName = productname;
        ProductStock = productstock;
        ProductCategoryID = productcategoryid;
        ProductEmployeeID = productemployeeid;
        ProductCreatedDate = DateTime.Now;
    }
}

Display products method in program :

static void DisplayProducts()
{
    List<Product> products = new List<Product>();
    Database db = new Database();
    SqlConnection conn = db.connection();
    conn.Open();

    using SqlCommand command = new SqlCommand(@"SELECT * FROM Products", conn);
    {
        SqlDataReader reader = command.ExecuteReader();

        while (reader.Read())
        {
            string productname = reader.GetString(1);
            int productstock = reader.GetInt32(2);
            int productcategoryid = reader.GetInt32(3);
            int productemployeeid = reader.GetInt32(4);

            products.Add(new Product() { ProductName = productname, ProductStock = productstock, 
                ProductCategoryID = productcategoryid, ProductEmployeeID = productemployeeid });
        }
    }

    foreach (Product product in products)
    {
        Console.WriteLine(product);
    }
}

and calling it from my main method :

static void Main(string[] args)
{
    DisplayProducts();
}      

In my DisplayProducts method, I get an error from doing this :

products.Add(new Product() { ProductName = productname, ProductStock = productstock, 
                        ProductCategoryID = productcategoryid, ProductEmployeeID = productemployeeid });

The error is:

There is no argument given that corresponds to the required formal parameter 'productname' of 'Product.product(string, int, int, int)'

I really don't know what that means, been googling and searching but found nothing so far.

Answer 1

It means that the constructor of Product need four arguments and you provide none.

Here's the signature of your constructor :

 // Constructor
    public Product(string productname, int productstock, int productcategoryid, int productemployeeid)

Change the line

products.Add(new Product() { ProductName = productname, ProductStock = productstock, 
                ProductCategoryID = productcategoryid, ProductEmployeeID = productemployeeid });

by this and you'll be fine

products.Add(new Product( productname, productstock, productcategoryid, productemployeeid));

Answer 2

1. When you do a select * from products, does the query return any result ?

You also need to start from 0, hence try to put reader.GetString(0)