两种构造方式,哪个好?有什么区别?
方式一:
public class SqlHelper
{
public SqlConnection Conn;
public SqlHelper()
{
Conn=new SqlConnection(ConfigurationSettings.AppSettings["MC"]);
}
}方式二:
public class SqlHelper
{
public SqlConnection Conn=new SqlConnection(ConfigurationSettings.AppSettings["MC"]);
}
方式一:
public class SqlHelper
{
public SqlConnection Conn;
public SqlHelper()
{
Conn=new SqlConnection(ConfigurationSettings.AppSettings["MC"]);
}
}方式二:
public class SqlHelper
{
public SqlConnection Conn=new SqlConnection(ConfigurationSettings.AppSettings["MC"]);
}
{
private SqlConnection conn;
public SqlConnection Connection
{
get
{
if (this.conn == null)
{
this.conn = new SqlConnection(ConfigurationSettings.AppSettings["MC"]);
}
return this.conn;
}
}
}建议不要使用 public 的成员变量,而是封装成属性。