Sql Update With Command.Parameters

 Im looking for example code to make a sql update...
 I want to use command.Parameters and variables from text boxes and i'm unsure how to do this...
 
Please help.
 
This code below doesn't work but it is an example of what i've been working with.. 
 <code>
     {   
            string conn = string.Empty;
            ConnectionStringsSection connectionStringsSection = WebConfigurationManager.GetSection("connectionStrings") as ConnectionStringsSection;
            if (connectionStringsSection != null)
            {
                ConnectionStringSettingsCollection connectStrings = connectionStringsSection.ConnectionStrings;
                ConnectionStringSettings connString = connectStrings["whowantsConnectionString"];
                conn = connString.ConnectionString;

                using (SqlConnection connection = new SqlConnection(conn))
                using (SqlCommand command = new SqlCommand("UPDATE users SET currentscore=5)", connection))
                {
                    updateCommand.Parameters.Add("@currentscore", SQLServerDbType.numeric, 18, "currentscore");
                    connection.Open();
                    command.ExecuteNonQuery();
                    connection.Close();
                }
            }
        }
</code>