C# System.InvalidOperationException:“Nullable object must have a value.”

System.InvalidOperationException:“Nullable object must have a value.”

经检查发现，是强制转换null值报的错。

解决方案

针对定义泛型数字类型的值运算时，使用三元运算符把null值转换为0

row.Amount = DoCalcAmount((decimal)(row.Qty ?? 0), (decimal)(row.Price ?? 0));