CheckOrder & CreateOrderAndDetails兩個View共用Controller的缺點

[timmyse2]

1. 非原作或不熟者(含原作)可能找不到關鍵
2. 它們的查詢邏輯相近, 分開容易漏改
3. Direction: make a share function is better

[timmyse2]

1. set a function
2. return ovm, not view

public async Task<OrderViewModel> TestOrderAsync(int? isSaveAndUpdat) 
{
     return _ovm;
}