C# (CSharp) ExpiryDate.Subtract示例

        public LicensingViewModel()
        {
            CustomerId      = ConfigurationHelper.GetConfigurationValue(ConfigurationConstants.CustomerId);
            SubscriptionKey = ConfigurationHelper.GetConfigurationValue(ConfigurationConstants.SubscriptionKey);
            string expiryDateString = ConfigurationHelper.GetConfigurationValue(ConfigurationConstants.ExpiryDate);

            ExpiryDate = !DateTime.TryParse(expiryDateString, out expiryDate) ? DateTime.Now : expiryDate;
            RemainDays = ExpiryDate.Subtract(DateTime.Today).Days;
            if (RemainDays < 0)
            {
                RemainDays = 0;
            }
        }