網站只能搜索或排序數據庫中的數據

Question

我已經爲大學創建了一個基本的電子商務網站，我遇到了排序和搜索我的產品表的問題，我的頁面顯示的產品很好。 該網站是在visual studio 2012中使用C＃使用剃鬚刀v2標記。

@{ 
    Layout = "~/_SiteLayout.cshtml"; 
    Page.Title = "Store"; 
    var db = Database.Open("StarterSite"); 
    string sql = ""; 

    switch (Request["sort"]) 
    { 
     case "PriceASC": 
      sql = "SELECT * FROM Products order by Product_Price ASC"; 
      break; 
     case "PriceDESC": 
      sql = "SELECT * FROM Products order by Product_Price DESC"; 
      break; 
     default: 
      sql = "SELECT * FROM PRODUCTS ORDER BY Product_ID"; 
      break; 
    } 

    if (Request["search"] != "") 
    { 
     sql = "SELECT * FROM Products where Product_Keywords like '%" + Request["search"] + "%'"; 
    } 
} 

這是我使用的，獨立它們都工作的代碼，但是當我把它們放在一起這樣的，哪一個是第二，接管並打破了第一。我已經多次交換過它們來測試這個，關於如何讓它們很好地協作的任何想法？

Answer 1

將它們組合起來不再有效的原因是因爲您正在覆蓋您在第一步中完成的查詢。我會做的是把這個過程分解成幾部分。

//declare your variable. I added a connection and command so I can include parameters in the process. 
string orderBy = ""; 
string whereClause = ""; 
string sql = ""; 

//create your order by clause 
switch (Request["sort"]) 
{ 
    case "PriceASC": 
     orderBy = "order by Product_Price ASC"; 
     break; 
    case "PriceDESC": 
     orderBy = "order by Product_Price DESC"; 
     break; 
    default: 
     orderBy = "ORDER BY Product_ID"; 
     break; 
} 

//create your where clause. 
if (!string.IsNullOrEmpty(Request["search"])) // forgot the ! here 
{ 
    whereClause = string.Format(" where Product_Keywords like '%{0}%'", Request["search"]); // very unsafe to plug this in. should use parameter 

} 

sql = string.Format("SELECT * FROM Products{0} {1}",whereClause, orderBy); //build your query string. if no search parameter was given the where clause will be blank, but the order by will still exist. 

@foreach (var row in db.Query(sql)) 
{ 
    //some code here 
}