c# - 将 overdueDate 从 DateTime 转换为格式为 dd/mm/yyyy 00 :00:00 的字符串

Question

我如何将 overdueDate 值从 DateTime 变量转换为 dd/mm/yyyy 00:00:00 ?

    DateTime overdueDate;
    DateTime today = DateTime.Now; 

    if (today.DayOfWeek == DayOfWeek.Monday)
    {
        overdueDate = today.AddDays(-12);
    }
    else if (today.DayOfWeek == DayOfWeek.Tuesday)
    {
        overdueDate = today.AddDays(-13);
    }
    else if (today.DayOfWeek == DayOfWeek.Wednesday)
    {
        overdueDate = today.AddDays(-7);
    }
    else if (today.DayOfWeek == DayOfWeek.Thursday)
    {
        overdueDate = today.AddDays(-8);
    }
    else if (today.DayOfWeek == DayOfWeek.Friday)
    {
        overdueDate = today.AddDays(-9);
    }
    else if (today.DayOfWeek == DayOfWeek.Saturday)
    {
        overdueDate = today.AddDays(-10);
    }
    else if (today.DayOfWeek == DayOfWeek.Sunday)
    {
        overdueDate = today.AddDays(-11);
    }

Answer 1

由于您只需要将时间设置为 00:00:00 的 Date 部分，您可以使用 DateTime.Date属性并将其格式化为:

string str = overdueDate.Date.ToString("dd/MM/yyy HH:mm:ss");

参见:Custom Date and Time Format Strings

你在声明的时候还没有初始化你的overdueDate，虽然你在你的条件下给它赋了一些值，但是编译器不能确定是否有任何值会被赋给它。因此你会得到错误“使用未分配的局部变量”。只需声明如下:

DateTime overdueDate = default(DateTime);