如何在C＃中将日期（来自日期时间输入字段）转换为另一种日期格式？

Question

I have Date time input field from where I am taking date and converting it to another format, my code for that

try
{
    DateTime dt = dtiFrom.Value.Date;
    string format = "DD-MM-YYYY"; // Use this format
    MessageBox.Show(dt.ToString(format)); // here its shows result as DD-10-YYYY
    DateTime dt1 = Convert.ToDateTime(dt.ToString(format)); // here Error "The string was not recognized as a valid DateTime. There is an unknown word starting at index 0."
}
catch (Exception ee)
{
    MessageBox.Show(ee.Message, "Error Message!");
}

I am not able to convert date according to my format. please could any body help me in code or suggest me some code. thanks in advance

Answer 1

Your format should be as follows:

string format = "dd-MM-yyyy";

Casing is important with string formatting, you may think it strange that the month uses upper-case, but this is because lower case m and mm is used to represent minutes.

Note that the reason your output displays DD and YYYY is because any character that is not reserved as a format character will be outputted with no change. Uppercase D and Y are not reserved which is why they display in the output, just as - remains unchanged.

If you wish to output reserved format characters then you can escape them using \\ .

See here for a full list of date and time format values

Answer 2

Date pattern format should be changed and better to use TryParseExact instead of using Convert

DateTime dt = dtiFrom.Value.Date;
string format = "dd-MM-yyyy";
DateTime dt1 = new DateTime();

if (DateTime.TryParseExact(dt , format, null , DateTimeStyles.None, out dt1))
{
  // you can use dt1 here
}
else
{
  MessageBox.Show("Error Massage");
}