使用最少的代码从 SQL 数据库行填充文本框

Question

I have a 'My User Account' web page with 18 controls that I want to populate from 18 columns in my Azure database. I have set the users login email as the session value 'New' which I use to search the database and find the corresponding row.

I am using the following code but I think this is slow in executing.

Can anyone suggest a more efficient way to code this?

try
{
    if (Session["New"] == null)
    {
        Response.Redirect("~/Account/Login.aspx"); //*****CHANGE REDIRECT WEBPAGE*****
    }
    else
    {
        string str = Convert.ToString(Session["New"]);
        string cpUsersConnection = ConfigurationManager.ConnectionStrings["cp_usersConnection"].ToString();
        SqlConnection oSqlConnection = new SqlConnection(cpUsersConnection);
        oSqlConnection.Open();
        SqlCommand oSqlCommand = new SqlCommand();
        oSqlCommand.Connection = oSqlConnection;
        oSqlCommand.CommandType = CommandType.Text;
        oSqlCommand.CommandText = "select account_no from users where email_1 = '" + str + "'";
        SqlDataAdapter oSqlDataAdapter = new SqlDataAdapter();
        oSqlDataAdapter.SelectCommand = oSqlCommand;
        SqlDataReader reader = oSqlCommand.ExecuteReader();

        if (reader.Read())
        {
            AcNo.Text = reader["account_no"].ToString();
        }

        string str1 = Convert.ToString(Session["New"]);
        string cpUsersConnection1 = ConfigurationManager.ConnectionStrings["cp_usersConnection"].ToString();
        SqlConnection oSqlConnection1 = new SqlConnection(cpUsersConnection);
        oSqlConnection.Open();
        SqlCommand oSqlCommand1 = new SqlCommand();
        oSqlCommand1.Connection = oSqlConnection;
        oSqlCommand1.CommandType = CommandType.Text;
        oSqlCommand1.CommandText = "select registration_date from users where email_1 = '" + str + "'";
        SqlDataAdapter oSqlDataAdapter1 = new SqlDataAdapter();
        oSqlDataAdapter1.SelectCommand = oSqlCommand1;
        SqlDataReader reader1 = oSqlCommand1.ExecuteReader();

        if (reader1.Read())
        {
            RegDate1.Text = reader1["registration_date"].ToString();
        }

    }
}
catch
{
    if (Session["New"] == null)
    {
        Response.Redirect("~/Account/Login.aspx"); //*****CHANGE REDIRECT WEBPAGE*****
    }

    AcNo.Text = "";
    RegDate1.Text = "";
    SetDBdateMessages.Text = "User Session Error - Please Contact Support";
}

Your thoughts are as always very much appreciated.

Answer 1

The SELECT statement in SQL allows to choose what fields you want to retrieve from your table. You are not limited to one field at time.

.....
string cmdText = @"select account_no,registration_date, other_field1, 
                   other_field2, other_fieldN
                   from users 
                   where email_1 = @email";

using(SqlConnection oSqlConnection = new SqlConnection(cpUsersConnection))
using(SqlCommand oSqlCommand = new SqlCommand(cmdText, oSqlConnection))
{
     oSqlConnection.Open();
     oSqlCommand.Parameters.Add("@email", SqlDbType.NVarChar).Value = str;
     using(SqlDataReader reader = oSqlCommand.ExecuteReader())
     {
        if (reader.Read())
        {
             AcNo.Text = reader["account_no"].ToString();
             RegDate1.Text = reader["registration_date"].ToString();
             otherTextBox.Text = reader["other_field1"].ToString();
             ... and so on ...
        }
    }
}

There are two things to highlight in this example:

• Define your sql statement declaring all the fields you want to retrieve with a single string and use parameter placeholders instead of string concatenations
• Put your disposable objects inside a using statement to correctly dispose them when you exit from the using block