写出优雅简明代码理论指导收集

   1. 不要使用””, 使用string.Empty 

     string name = string.Empty;

2. 善于合并if

   public bool Equals(CommentData obj) {
      if (!CommentId.Equals(obj.CommentId)) return false;
      if (!Comment.Equals(obj.Comment)) return false;
      if (!CommentorId.Equals(obj.CommentorId)) return false;
      return true;
    }

     --------->>>

      public bool Equals(CommentData obj) {
         return CommentId == obj.CommentId &&
         Comment.Equals(obj.Comment) &&
         CommentorId == obj.CommentorId;
      }

   

    3. 不断重构你的代码

     4. 用 Linq 简化代码

    foreach (CommentData data in Comments)
            {
                if (data.CommentId.HasValue)
                    throw new ArgumentNullException("Create is only for saving new data.  Call save for existing data.", "data");
            }

--------------->>>

 if (Comments.Any(data => data.CommentId.HasValue))
            {
                throw new ArgumentNullException("Create is only for saving new data.  Call save for existing data.", "data");
            }
5. 运用 ？：和？？

string name = value;   
if (value == null)
{
name = string.Empty;
}
------------>>>
string name = (value != null) ? value : string.Empty;
或: string name = value ?? string.Empty;
6.运用AS
if (employee is SalariedEmployee)

{
    var salEmp = (SalariedEmployee)employee;
    pay = salEmp.WeeklySalary;
    // ...
}
----------------------------------->>>

var salEmployee = employee as SalariedEmployee;
if (salEmployee != null)
{
   pay = salEmployee.WeeklySalary;
    // ...
}

7. 运用 using, 去除dispose（）
public IEnumerable<Order> GetOrders()
{
    SqlConnection con = null;
    SqlCommand cmd = null;
    SqlDataReader rs = null;
    var orders = new List<Order>();
    try
    {
        con = new SqlConnection("some connection string");
        cmd = new SqlCommand("select * from orders", con);
        rs = cmd.ExecuteReader();
        while (rs.Read())
        {
            // ...
        }
    }
    finally
    {
        rs.Dispose();
        cmd.Dispose();
        con.Dispose();
    }
    return orders;
}


------------------------------->>>
public IEnumerable<Order> GetOrders()

{

    var orders = new List<Order>(); 
   using (var con = new SqlConnection("some connection string"))
    {
        using (var cmd = new SqlCommand("select * from orders", con))
        {
            using (var rs = cmd.ExecuteReader())
            {
                while (rs.Read())
                {

                    // ...

                }

            }

        }

    } 
    return orders;
} 


再次简化：
 public IEnumerable<Order> GetOrders()
{

    var orders = new List<Order>(); 

    using (var con = new SqlConnection("some connection string"))
    using (var cmd = new SqlCommand("select * from orders", con))
    using (var rs = cmd.ExecuteReader())
    {
        while (rs.Read())
        {
           // ...
        }
    } 
    return orders;

}