Question

I’m a beginner and trying to do something you all find simple. I’d like to run a SQL select on page load in my CS and access that data from my ASPX, the following is my default.cs code:

public partial class _Default : System.Web.UI.Page
{
private SqlDataReader reader = null;
public SqlDataReader Reader { get { return reader; } set { reader = value; } }

    protected void Page_Load(object sender, EventArgs e)
    {
    string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ToString();
    using (SqlConnection connection = new SqlConnection(connectionString)) {
    connection.Open();

    using (SqlCommand command = new SqlCommand("SELECT * FROM uploads WHERE status IS NULL AND uploader = @uploader", connection)) {
        command.Parameters.Add(new SqlParameter("uploader", "anonymous"));

        Reader = command.ExecuteReader();
    }
    }
    }
}

in my aspx I’m trying to use something like:

<%= Reader.GetString(1) %>

but I keep getting the following errors:
Exception Details: System.InvalidOperationException: Invalid attempt to call MetaData when reader is closed.

I know that my using statement is closing the connection when it ends, but I’m not sure why I cannot access the data from my ASPX. If I use the same GetString(1) value within the using loop I can access the relevant data fine.

I’m basically just trying to output all the rows in my results =\

Answer 1

You should really be updating your page from inside the “using” block. In its simplest form, you could add a Literal control to your page, and update it in the using block:

Reader = command.ExecuteReader();
...
Literal1.Text = Reader.GetString(1);

When you use the following syntax in your markup:

<%= Reader.GetString(1) %>   

the compiler will generate a Response.Write statement that is executed during the Render phase of the page life cycle. In your case, the connection is disposed by then.

You could keep the connection and reader alive, and dispose of it in an override of the page’s Dispose method, but I wouldn’t recommend this approach.