将分钟添加到日期不会更改Date C#.NET

Question

double TotalMinute = 300.0 double TotalMinutesAdded = 1378.0

double TotalMinute=300.0
double TotalMinutesAdded=1378.0

foreach(DataRow dr in ds.Tables[0].Rows)
                {

                    //Add The above Timings to each Row's 2nd Column
                    DateTime correctDate=Convert.ToDateTime(dr[2]);

                    correctDate.AddMinutes(TotalMinute);
                    correctDate.AddMinutes(TotalMinutesAdded);

                    dr[2]=correctDate;

                }

Answer 1

DateTiem添加*函数不应更改当前的DateTime值.他们返回新的价值.

如果您希望更改值,请键入如下:

correctDate = correctDate.AddMinutes(TotalMinute);

Answer 2

DateTime是不可变的; 像AddMinutes这样的函数返回一个新的 DateTime; 所以你需要捕获返回的值:

DateTime foo = ...
DateTime bar = foo.AddMinutes(5);

Answer 3

如上所述,由于DateTime对象是不可变的,您必须重新分配变量.

但是,需要注意的是,您可以将操作链接为:

correctDate = correctDate.AddMinutes(TotalMinute)
                         .AddMinutes(TotalMinutesAdded);