c# - 使用 Linq 计算 ObservableCollection 值的总和

Question

这是我的代码示例

class Gold
{
    public String Category { get; set; }
    public Double Weight { get; set; }
}
class Metal
{
    public ObservableCollection<Gold> GoldCollection { get; set; }
    public String Name { get; set; }
    public Double Amount { get; set; }
}
class Collection
{
    public ObservableCollection<Metal> MetalCollection { get; set; }
    public String Category { get; set; }
    public Double TotalWeight { get; set; }
}

如何使用 LINQ 从集合模型中计算按类别分组的黄金权重？

Answer 1

给你:

Collection obj = new Collection();

obj.MetalCollection.SelectMany(m => m.GoldCollection).GroupBy(g => g.Category).Select(t => new { t.Key, MySum = t.Sum(n => n.Weight).ToString() });