使用 TryParseExact 解析到日期时间，那么的ToString 与格式字符串转换回...

Use TryParseExact to parse to a DateTime, then ToString with a format string to convert back...

DateTime dt;
if (DateTime.TryParseExact(value, "MM/dd/yyyy hh:mm:ss tt",
                           CultureInfo.InvariantCulture, DateTimeStyles.None,
                           out dt))
{
    string text = dt.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);
    // Use text
}
else
{
    // Handle failure
}