我的排序没有正确返回 [英] My sorting is not returning correctly

问题描述

有人可以指出我的排序为什么不工作？我没有得到错误，方法只是返回列表没有排序。

  public IEnumerable< Customer> GetSubsetOfEmployees（int startRows，int maxRows，string sortExpression）
 {
 NorthwindEntities ndc = new NorthwindEntities（）; 
 var customerQuery = 
 from c in ndc.Customers 
 //https://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b 
 select c; 
 
 if（string.IsNullOrEmpty（sortExpression））sortExpression =CustomerID; 
 
字典< string，Func< IEnumerable< Customer>，IEnumerable< Customer>>> orderings = new Dictionary< string，Func< IEnumerable< Customer>，IEnumerable< Customer>>（）
 {
 {CustomerID，x1 => x1.OrderBy（x => x.CustomerID）}，
 {CompanyName，x1 => x1.OrderBy（x => x.CompanyName）}，
 {CustomerID DESC，x1 => x1.OrderByDescending（x => x.CustomerID）}，
}; 
 
 orderings [sortExpression]（customerQuery.Skip（startRows）.Take（maxRows））; 
 
返回customerQuery; 
} 
  

解决方案

  IEnumerable< Customer> result = orderings [sortExpression]（customerQuery.Skip（startRows）.Take（maxRows））; 
返回结果; 
  

Can someone please point out why my sorting is not working? I'm not getting an error, method just returns list not sorted.

public IEnumerable<Customer> GetSubsetOfEmployees(int startRows, int maxRows, string sortExpression)
{
    NorthwindEntities ndc = new NorthwindEntities();
    var customerQuery =
        from c in ndc.Customers
            //https://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b
        select c;

    if (string.IsNullOrEmpty(sortExpression)) sortExpression = "CustomerID";

    Dictionary<string, Func<IEnumerable<Customer>, IEnumerable<Customer>>> orderings = new Dictionary<string, Func<IEnumerable<Customer>, IEnumerable<Customer>>>()
    {
        { "CustomerID",  x1 => x1.OrderBy(x => x.CustomerID) },
        { "CompanyName",  x1 => x1.OrderBy(x => x.CompanyName) },
        { "CustomerID DESC",  x1 => x1.OrderByDescending(x => x.CustomerID) },
    };

    orderings[sortExpression](customerQuery.Skip(startRows).Take(maxRows));

    return customerQuery;
}

解决方案

You are not returning the sorted collection.

IEnumerable<Customer> result = orderings[sortExpression](customerQuery.Skip(startRows).Take(maxRows));
return result;

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