如何计算 IEnumerable 中出现的次数

Question

我的 razor 页面中有这个 IEnumerable 方法。

        @if (Orders.Any())
        {
            <table class="table table-bordered">
                <thead>
                   
                    <th>Driver Name</th>
                    <th>Delivery Orders</th>
                </thead>
                <tbody>
                    @foreach(var objOrders in Orders)
                    {
                    <tr>
                        <th>
                            @objOrders.Driver.UserName
                        </th>
                        <th>
                            @objOrders.Driver.FullName.Count()
                        </th>
                        <td>
                        </td>
                    </tr>
                    }
                </tbody>
            </table>
        }

来自这里

private IEnumerable<OrderDTO> Orders { get; set; } = new List<OrderDTO>();

    private bool IsLoading { get; set; } = true;

    public async Task SearchDate()
    {

        Orders =  await _orderRepository.GetDate(DateValue);
    }
    private async Task LoadOrders()
    {
        IsLoading=true;
        StateHasChanged();
        await SearchDate();
        
        //Orders = await _orderRepository.GetDate(date);
        IsLoading = false;
        StateHasChanged();
    }

这里

public async Task<IEnumerable<OrderDTO>> GetDate(DateTime date)
    {
            if (date != null)
            {
                return _mapper.Map<IEnumerable<Order>, IEnumerable<OrderDTO>>
                   ((IEnumerable<Order>)_db.Orders.Where(u => u.DeliveryDate == date));
            }
            else
            {
                return _mapper.Map<IEnumerable<Order>, IEnumerable<OrderDTO>>(_db.Orders);
            }
        }

现在，显示是这样的

|Driver Name          | Number Delivery Orders |
| :---                |    :----:   | 
| 1                   | 1  |
| 1                   | 1  |
| 2                   | 1  |
|Kim1                 | 4  |

而我想这样显示

|Driver Name          | Number Delivery Orders |
| :---                |    :----:   | 
| 1                   | 2 (Occurrences)  |
| 2                   | 1 (Occurrences)  |
|Kim1                 | 1 (Occurrences)  |

我知道现在 Count() 方法正在计算 driver 名称的长度，但是我该如何编码才能使 return driver的名字。

谢谢大家。

Answer 1

@foreach(var objOrders in Orders
    .GroupBy(u => u.Driver.FullName)
    .Select(group => new {
        Count= group.Count(),
        Key=group.Key }
    )
)

设法做到这一点。感谢@Martin Costello

如何计算 IEnumerable 中出现的次数

How Do I count the number of occurrences in the IEnumerable

c#

linq

entity-framework

blazor