Linq動態表

Question

linq有使用字符串來調用表的方法嗎？我嘗試了linq動態，但沒有找到我在找什麼。所以基本上我會說我傳遞一個參數字符串，我會用它來打電話給我表：

例如：

public IEnumerable<Category> SearchInTable(string table) 

var context = new MapEntities() ; 

myTable = context.Tables[table]; // something like that. Table == Country 

return myTable.Where(x => x.name.Contains("Canada")).OrderByDescending(o => o.id).Take(10); 

我希望我是清楚的！謝謝

Answer 1

public IQueryable<Category> SearchInTable(string table) 
{ 
    var context = new MapEntities(); 
    IQueryable<Category> myTable; 
    switch(table) 
    { 
    case "Canada": myTable=context.Canada; break; 
    case "UnitedStates": myTable=context.UnitedStates; break; 
    else throw new Exception("Table not found"); 
    } 
    return myTable.Where(x => x.name.Contains("Canada")).OrderByDescending(o => o.id).Take(10); 
} 

雖然你應該打破這種分離：

public static IQueryable<Category> GetTable(this DataContext context,string table) 
{ 
    IQueryable<Category> myTable; 
    switch(table) 
    { 
    case "Canada": myTable=context.Canada; break; 
    case "UnitedStates": myTable=context.UnitedStates; break; 
    else throw new Exception("Table not found"); 
    } 
    return myTable; 
} 

public static IQueryable<Category> Search(this IQueryable<Category> context) 
{ 
    return context.Where(x => x.name.Contains("Canada")).OrderByDescending(o => o.id).Take(10); 
} 

，那麼你可以這樣做：

var result=new MapEntities().GetTable("Canada").Search(); 

（我可能不會放。取（10）在搜索中，我會想出一個更好的名稱，比如ContainsCanada，或者使搜索更具通用性）