LINQ兒童擴展方法

Question

我創建了一個LINQ擴展，就像談到here一樣。但顯然，它不適用於對孩子的查詢。

return (from p in repository.GetResources() 
       where p.ResourceNames.Any(r => r.Name.WhereIn(arg => arg.Name, "PartialWord")) 
       select p).ToList(); 

我想做到的是，ResourceNames是EntityCollection，我需要檢查，如果孩子的財產「名稱」，看看他們是否包含單詞「PartialWord」：如下面的代碼所示。

，其中適用於這樣的：

repository.GetResources().WhereIn({CODEHERE}); 

但當放置於兒童，這是行不通的。有沒有特別的方法來設置我的擴展。這是它下面：

public static class QueryableExtensions 
{ 
    private static Expression<Func<TElement, bool>> GetWhereInExpression<TElement, TValue>(Expression<Func<TElement, TValue>> propertySelector, IEnumerable<TValue> values) 
    { 
     ParameterExpression p = propertySelector.Parameters.Single(); 
     if (!values.Any()) 
      return e => false; 

     var equals = values.Select(value => (Expression)Expression.Equal(propertySelector.Body, Expression.Constant(value, typeof(TValue)))); 
     var body = equals.Aggregate<Expression>((accumulate, equal) => Expression.Or(accumulate, equal)); 

     return Expression.Lambda<Func<TElement, bool>>(body, p); 
    } 

    /// <summary> 
    /// Return the element that the specified property's value is contained in the specifiec values 
    /// </summary> 
    /// <typeparam name="TElement">The type of the element.</typeparam> 
    /// <typeparam name="TValue">The type of the values.</typeparam> 
    /// <param name="source">The source.</param> 
    /// <param name="propertySelector">The property to be tested.</param> 
    /// <param name="values">The accepted values of the property.</param> 
    /// <returns>The accepted elements.</returns> 
    public static IQueryable<TElement> WhereIn<TElement, TValue>(this IQueryable<TElement> source, Expression<Func<TElement, TValue>> propertySelector, params TValue[] values) 
    { 
     return source.Where(GetWhereInExpression(propertySelector, values)); 
    } 

    /// <summary> 
    /// Return the element that the specified property's value is contained in the specifiec values 
    /// </summary> 
    /// <typeparam name="TElement">The type of the element.</typeparam> 
    /// <typeparam name="TValue">The type of the values.</typeparam> 
    /// <param name="source">The source.</param> 
    /// <param name="propertySelector">The property to be tested.</param> 
    /// <param name="values">The accepted values of the property.</param> 
    /// <returns>The accepted elements.</returns> 
    public static IQueryable<TElement> WhereIn<TElement, TValue>(this IQueryable<TElement> source, Expression<Func<TElement, TValue>> propertySelector, IEnumerable<TValue> values) 
    { 
     return source.Where(GetWhereInExpression(propertySelector, values)); 
    } 
} 

Answer 1

。假定ResourceName.Name是一個字符串：

You don't need any extension for the string version of .Contains() in L2E。 （您需要做僅用於L2E v.1中的列表版本）。你應該可以這樣做：

return (from p in repository.GetResources() 
     where p.ResourceNames.Any(r => r.Name.Contains("PartialWord")) 
     select p).ToList();