使用最少代码从 SQL 数据库行填充文本框

Question

我有一个“我的用户帐户”网页，其中包含 18 个控件，我想从我的 Azure 数据库中的 18 列中填充这些控件。我已将用户登录电子邮件设置为会话值“新”，用于搜索数据库并找到相应的行。

我正在使用以下代码，但我认为这执行起来很慢。

谁能建议一种更有效的编码方式？

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";
}

一如既往地非常感谢您的想法。

Answer 1

SQL 中的 SELECT 语句允许选择要从表中检索的字段。您一次不限于一个字段。

.....
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 ...
        }
    }
}

在这个例子中有两点需要强调：

• 定义您的 sql 语句，用单个字符串声明您要检索的所有字段，并使用参数占位符而不是字符串连接
• 将一次性对象放入 using 语句中以正确 当你退出 using 块时处理它们