減少的（我）的LINQ列表排序

Question

冗長我有一個類型DataTable進行排序只是類似：

DataTable.DefaultView.Sort("sortexpression"); 

因爲排序表達式是一個字符串，我可以只添加這兩種排序字段和方向幾行，不管我有多少種排序選項。現在使用LINQ林清楚地做一些非常錯誤的，因爲做同樣的事情，我這樣做：

   this.GetSortExpressions(); 
     if ((ViewState["SortDirection"] as string) == "ASC") 
     { 
      switch (ViewState["SortField"] as string) 
      { 
       case "LKey": 
        this.SortedDetails = this.Details.OrderBy(d => d.LKey); 
        break; 
       case "MName": 
        this.SortedDetails = this.Details.OrderBy(d => d.MaterialName); 
        break; 
       case "FMSQOH": 
        this.SortedDetails = this.Details.OrderBy(d => d.FMSQOH); 
        break; 
       case "CCQOH": 
        this.SortedDetails = this.Details.OrderBy(d => d.CCQOH); 
        break; 
       case "FMSQOHVary": 
        this.SortedDetails = this.Details.OrderBy(d => d.FMSQOHVary); 
        break; 
       default: 
        this.SortedDetails = this.Details.OrderBy(d => d.LKey); 
        break; 
      } 
     } 
     else 
     { 
      switch (ViewState["SortField"] as string) 
      { 
       case "LKey": 
        this.SortedDetails = this.Details.OrderByDescending(d => d.LKey); 
        break; 
       case "MName": 
        this.SortedDetails = this.Details.OrderByDescending(d => d.MaterialName); 
        break; 
       case "FMSQOH": 
        this.SortedDetails = this.Details.OrderByDescending(d => d.FMSQOH); 
        break; 
       case "CCQOH": 
        this.SortedDetails = this.Details.OrderByDescending(d => d.CCQOH); 
        break; 
       case "FMSQOHVary": 
        this.SortedDetails = this.Details.OrderByDescending(d => d.FMSQOHVary); 
        break; 
       default: 
        this.SortedDetails = this.Details.OrderByDescending(d => d.LKey); 
        break; 
      } 
     } 

這是上帝可怕。我很擔心我爲每個新的排序字段添加2 * n個case語句。什麼是正確的方式？執行排序（未經測試）之前

Answer 1

我已經通過這個走了..我發現最後是使用反射來排序的IEnumerable對象的通用解決方案。

http://zhousanfeng.wordpress.com/2009/12/01/a-generic-comparersorter-class%E8%BD%AC/

這將是你如何使用它

Sorter<TestClass> sort = new Sorter<TestClass>(this.Deatils, "LKey ASC"); 
List<TestClass> sorted = sort.GetSortedList(); 

問候。

Answer 2

分配Func的排序依據方法：

public IOrderedEnumerable<TSource> OrderFunc<TSource, TKey>(
    this IEnumerable<TSource> source, 
    Func<TSource, TKey> keySelector 
); 
OrderFunc order; 
if ((ViewState["SortDirection"] as string) == "ASC") 
    order = Enumerable.OrderBy; 
else 
    order = Enumerable.OrderByDescending; 

switch (ViewState["SortField"] as string) 
{ 
    case "LKey": 
     this.SortedDetails = order(this.Details, d => d.LKey); 
    break; 
    case "MName": 
     this.SortedDetails = order(this.Details, d => d.MaterialName); 
    break; 
    case "FMSQOH": 
     this.SortedDetails = order(this.Details, d => d.FMSQOH); 
    break; 
    case "CCQOH": 
     this.SortedDetails = order(this.Details, d => d.CCQOH); 
    break; 
    case "FMSQOHVary": 
     this.SortedDetails = order(this.Details, d => d.FMSQOHVary); 
    break; 
    default: 
     this.SortedDetails = order(this.Details, d => dLKey); 
    break; 
}