執行或兩個LINQ IQueryables

Question

我有兩個IQueryables的：

public static IQueryable<Counterparty> SearchByCode(this IQueryable<Counterparty> queryable, string searchQuery) 
    { 
     return queryable.Where(x => x.Code.StartsWith(searchQuery.ToUpper())); 
    } 

    public static IQueryable<Counterparty> SearchByName(this IQueryable<Counterparty> queryable, string searchQuery) 
    { 
     return queryable.Where(x => x.Name.ToLower().Contains(searchQuery.ToLower())); 
    } 

我想創建另一個IQueryable的它結合了兩個查詢作爲或EG

public static IQueryable<Counterparty> SearchByCodeOrName(this IQueryable<Counterparty> queryable, string searchQuery) 
    { 
     // return SearchByName(searchQuery) OR SearchByCode(searchQuery) 
    } 

我寧願避免重複的代碼，所以我想重複使用現有的查詢語句，而不是重寫一個新的lambda表達式，如Where(x=> x.Code.StartsWith.... || x.Name.Contains.....)

Answer 1

取決於你希望能夠重用什麼樣的代碼，這可能是做這件事，你不重複的查詢條件的內部運作的另一種方式：

private static Func<Counterparty, string, bool> CodeStartsWith = (x, searchQuery) => x.Code.StartsWith(searchQuery.ToUpper()); 

    private static Func<Counterparty, string, bool> NameContains = (x, searchQuery) => x.Name.Contains(searchQuery.ToLower()); 

    public static IQueryable<Counterparty> SearchByCode(this IQueryable<Counterparty> queryable, string searchQuery) 
    { 
     return queryable.Where(x => CodeStartsWith(x, searchQuery)); 
    } 

    public static IQueryable<Counterparty> SearchByName(this IQueryable<Counterparty> queryable, string searchQuery) 
    { 
     return queryable.Where(x => NameContains(x, searchQuery)); 
    } 

    public static IQueryable<Counterparty> SearchByCodeOrName(this IQueryable<Counterparty> queryable, string searchQuery) 
    { 
     return queryable.Where(x => NameContains(x, searchQuery) || CodeStartsWith(x, searchQuery)); 
    } 

Answer 2

您可以將兩者的結果聯合起來

public static IQueryable<Counterparty> SearchByCodeOrName(this IQueryable<Counterparty> queryable, string searchQuery) 
{ 
    return SearchByName(searchQuery).Union(SearchByCode(searchQuery)) 
}