如何在C#中计算Proto消息Affordability的总支出与剩余金额

首先，确保你已经通过Proto编译器将.proto文件生成了对应的C#类，生成的Affordability类会包含你定义的所有decimal类型属性。

直接计算实现 #

如果只是单次计算需求，直接对实例属性做加减运算即可：

// 假设已获取到Affordability实例
var affordability = new Affordability
{
    Salary = 8000.00m,
    Accomodation = 2500.00m,
    PhoneBill = 300.00m,
    Utilities = 800.00m
};

// 计算总支出
decimal totalExpenses = affordability.Accomodation + affordability.PhoneBill + affordability.Utilities;
// 计算剩余金额
decimal amountLeft = affordability.Salary - totalExpenses;

// 输出结果
Console.WriteLine($"总支出：{totalExpenses:C}，剩余金额：{amountLeft:C}");

扩展方法实现（推荐复用场景） #

如果需要在多处复用计算逻辑，给Affordability类写扩展方法会让代码更简洁易维护：

public static class AffordabilityExtensions
{
    /// <summary>
    /// 计算总支出（accomodation + phone_bill + utilities）
    /// </summary>
    public static decimal GetTotalExpenses(this Affordability affordability)
    {
        return affordability.Accomodation + affordability.PhoneBill + affordability.Utilities;
    }

    /// <summary>
    /// 计算剩余金额（salary - 总支出）
    /// </summary>
    public static decimal GetAmountLeft(this Affordability affordability)
    {
        return affordability.Salary - affordability.GetTotalExpenses();
    }
}

调用扩展方法的示例：

var affordability = new Affordability
{
    Salary = 8000.00m,
    Accomodation = 2500.00m,
    PhoneBill = 300.00m,
    Utilities = 800.00m
};

decimal totalExpenses = affordability.GetTotalExpenses();
decimal amountLeft = affordability.GetAmountLeft();

Console.WriteLine($"总支出：{totalExpenses:C}，剩余金额：{amountLeft:C}");

注意事项 #

• 核对编译后的属性名：Proto中下划线命名（如phone_bill）默认会被编译为帕斯卡命名（如PhoneBill），请以实际生成的C#类属性名为准。
• 处理默认值：如果属性未赋值，decimal类型默认值为0，上述逻辑依然有效；若需处理特殊场景（如薪资为0的提示），可在方法中添加额外判断。

内容的提问来源于stack exchange，提问作者Chief_Muna