Question

Trying to do a recordset, I just want one column of data, but this code is giving me an error.. I’m an ASP.NET newb, can anyone help?:

System.Data.SqlClient.SqlException: Invalid column name
‘CustomerName’.

 using (SqlConnection con = new SqlConnection(DB.GetDBConn()))
 {
  con.Open();
  using (IDataReader dr = DB.GetRS("select CustomerName from Customer where CustomerID=" + Customer.CustomerID, con))
   {
       string CustomerName = "CustomerName";                    
   }
 }

 String EncCustomerName = Encrypt(CustomerName.Replace(".", "").Replace("-", ""),"1");

Question #2: How do I bind the database content to the CustomerName string? It seems like its only returning “CustomerName” as the value for CustomerName string.. I would like it to return the database data for CustomerName string.. Help?

Suggested to use a ExecuteScalar, so i modified the request to this

   using (var con = new SqlConnection(DB.GetDBConn()))
   using (var cmdContrib = new SqlCommand("SELECT CustomerName FROM Customer WHERE   CustomerID=" + ThisCustomer.CustomerID, con))

   {

        con.Open();
        string CustomerName = cmdContrib.ExecuteScalar();
   } 

And i Get this error:
“string CustomerName = cmdCust.ExecuteScalar();”

CS0266: Cannot implicitly convert type ‘object’ to ‘string’. An explicit conversion exists (are you missing a cast?)

Answer 1

To answer your second question:

// Set it here so you can access it outside the scope of the using statement
string CustomerName = "";

using (SqlConnection con = new SqlConnection(DB.GetDBConn()))
{
    con.Open();
    using (IDataReader dr = DB.GetRS("select CustomerName from Customer where CustomerID=" + Customer.CustomerID, con))
    {
        while (dr.Read())
            CustomerName = dr["CustomerName"].ToString();
        }                    
    }
 }

If you’re sure you’ll only get one CustomerName result, using a DataReader is a bit of an overkill.

SqlCommand.ExecuteScalar Example

string CustomerName = "";

using (SqlConnection con = new SqlConnection(DB.GetDBConn()))
{

    SqlCommand cmd = new SqlCommand("SELECT CustomerName FROM Customer WHERE CustomerID = " + Customer.CustomerID, con);
    cmd.CommandType = CommandType.Text;

    con.Open();

    CustomerName = Convert.ToString(cmd.ExecuteScalar());

}

SqlCommand.ExecuteScalar Method

Additional Info

ExecuteScalar returns an object, so you’ll need to convert the returned value to the proper type (in this case, string).

Also, you should declare your CustomerName value outside of the using blocks (as I did in my example) – otherwise it will be scoped to the using blocks and not available outside of them.