C＃30 Days from Todays Date
我需要我的应用程序从今天起30天过期，我将当前日期存储在应用程序配置中。如何检查应用程序是否已过期？ 我不介意用户是否更改了时钟并且应用程序正常工作（用户太愚蠢了）。
if (appmode == "Trial") { ???? } string dateInString = "01.10.2009"; DateTime startDate = DateTime.Parse(dateInString); DateTime expiryDate = startDate.AddDays(30); if (DateTime.Now > expiryDate) { //... trial expired }
DateTime.AddDays这样做：
DateTime expires = yourDate.AddDays(30);
DateTime.Now.Add（-30）
给你30天后的日期
一个我可以自信地回答！
DateTime expiryDate = DateTime.Now.AddDays(30);
或者可能 – 如果您只是希望没有附加时间的日期可能更合适：
DateTime expiryDate = DateTime.Today.AddDays(30);
DateTime _expiryDate = DateTime.Now + TimeSpan.FromDays(30);
可能的解决方案是首次运行，创建一个包含当前日期的文件并将其放入IsolatedStorage。 对于后续运行，检查文件的内容并与当前日期进行比较; 如果日期差异大于30天，请通知用户并关闭应用程序。
更好的解决方案可能是引入带有计数器的许可证文件。 将许可证文件写入应用程序的安装日期（安装期间）。 然后，每次运行应用程序时，您都可以编辑许可证文件并将计数递增1.每次应用程序启动时，您只需快速检查是否已达到应用程序的30次使用即ie
if (LicenseFile.Counter == 30) // go into expired mode
如果用户已将系统时钟恢复原状，这也将解决问题，因为您可以进行简单的检查
if (LicenseFile.InstallationDate < SystemDate) // go into expired mode (as punishment for trying to trick the app!)
您当前设置的问题是用户必须每天使用该应用程序30天才能完成30天的试用期。
string[] servers = new string[] { "nist1-ny.ustiming.org", "nist1-nj.ustiming.org", "nist1-pa.ustiming.org", "time-a.nist.gov", "time-b.nist.gov", "nist1.aol-va.symmetricom.com", "nist1.columbiacountyga.gov", "nist1-chi.ustiming.org", "nist.expertsmi.com", "nist.netservicesgroup.com" }; string dateStart, dateEnd; void SetDateToday() { Random rnd = new Random(); DateTime result = new DateTime(); int found = 0; foreach (string server in servers.OrderBy(s => rnd.NextDouble()).Take(5)) { Console.Write("."); try { string serverResponse = string.Empty; using (var reader = new StreamReader(new System.Net.Sockets.TcpClient(server, 13).GetStream())) { serverResponse = reader.ReadToEnd(); Console.WriteLine(serverResponse); } if (!string.IsNullOrEmpty(serverResponse)) { string[] tokens = serverResponse.Split(' '); string[] date = tokens[1].Split(' '); string time = tokens[2]; string properTime; dateStart = date[2] + "/" + date[0] + "/" + date[1]; int month = Convert.ToInt16(date[0]), day = Convert.ToInt16(date[2]), year = Convert.ToInt16(date[1]); day = day + 30; if ((month % 2) == 0) { //MAX DAYS IS 30 if (day > 30) { day = day - 30; month++; if (month > 12) { month = 1; year++; } } } else { //MAX DAYS IS 31 if (day > 31) { day = day - 31; month++; if (month > 12) { month = 1; year++; } } } string sday, smonth; if (day < 10) { sday = "0" + day; } if (month < 10) { smonth = "0" + month; } dateEnd = sday + "/" + smonth + "/" + year.ToString(); } } catch { // Ignore exception and try the next server } } if (found == 0) { MessageBox.Show(this, "Internet Connection is required to complete Registration. Please check your internet connection and try again.", "Not connected", MessageBoxButtons.OK, MessageBoxIcon.Information); Success = false; } }
我在某些网站的某些部分看到了这些代码。 上面的示例暴露了一个小故障：将当前时间和日期更改为开始日期将延长应用程序到期时间。
解决方案？ 请参阅在线时间服务器。
@Ed courtenay，@ James，我有一个愚蠢的问题。 如何让用户远离此文件？（包含失效日期的文件）。 如果用户具有安装权限，那么显然用户也可以访问查看文件。 更改文件的扩展名不会有帮助。 那么，如何保持这个文件安全并远离用户手中？
您需要存储程序的第一个运行时才能执行此操作。 我怎么可能这样做是使用visual studio中的内置应用程序设置。 制作一个名为InstallDate的用户设置，默认为DateTime.MinValue或类似的东西（例如1/1/1900）。
然后当程序运行时，检查很简单：
if (appmode == "trial") { // If the FirstRunDate is MinValue, it's the first run, so set this value up if (Properties.Settings.Default.FirstRunDate == DateTime.MinValue) { Properties.Settings.Default.FirstRunDate = DateTime.Now; Properties.Settings.Default.Save(); } // Now check whether 30 days have passed since the first run date if (Properties.Settings.Default.FirstRunDate.AddMonths(1) < DateTime.Now) { // Do whatever you want to do on expiry (exception message/shut down/etc.) } }
用户设置存储在一个非常奇怪的位置（类似于C：\ Documents and Settings \ YourName \ Local Settings \ Application Data），因此无论如何平均乔很难找到它。 如果你想成为偏执狂，只需加密日期，然后再将其保存到设置中。
编辑：叹了口气，误读了这个问题，没有像我想象的那么复杂。>
if (cmb_mode_of_service.SelectedItem != null && cmb_term_of_service.SelectedItem != null) { if (cmb_mode_of_service.SelectedIndex > 0 && cmb_term_of_service.SelectedIndex > 0) { if (cmb_mode_of_service.SelectedItem.ToString() == "Single Service/Installation" || cmb_term_of_service.SelectedItem.ToString() == "Single Time") { int c2 = 1; char c1 = 'A'; DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = service_start_date.Text; dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; dt.Rows.Add(dr); dataGridView1.DataSource = dt; txtexpirydate.Text = (Convert.ToDateTime(service_start_date.Text).AddDays(1)).ToString(); } else { if (cmb_mode_of_service.SelectedItem.ToString() == "Weekly Service") { int year = 0; if (cmb_term_of_service.SelectedItem.ToString() == "One Year") { year = 1; } if (cmb_term_of_service.SelectedItem.ToString() == "Two Year") { year = 2; } if (cmb_term_of_service.SelectedItem.ToString() == "three year") { year = 3; } DateTime currentdate = Convert.ToDateTime(service_start_date.Text); DateTime Enddate = currentdate.AddYears(+year); txtexpirydate.Text = Enddate.ToString(); char c1 = 'A'; int c2 = 1; for (var dt1 = currentdate.AddDays(7); dt1 <= Enddate; dt1 = dt1.AddDays(7)) { DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = dt1.ToString(); dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; //txtexpirydate.Text = dt1.ToString(); dt.Rows.Add(dr); } dataGridView1.DataSource = dt; } if (cmb_mode_of_service.SelectedItem.ToString() == "Fortnight Service") { int year = 0; if (cmb_term_of_service.SelectedItem.ToString() == "One Year") { year = 1; } if (cmb_term_of_service.SelectedItem.ToString() == "Two Year") { year = 2; } if (cmb_term_of_service.SelectedItem.ToString() == "three year") { year = 3; } DateTime currentdate = Convert.ToDateTime(service_start_date.Text); DateTime Enddate = currentdate.AddYears(+year); txtexpirydate.Text = Enddate.ToString(); char c1 = 'A'; int c2 = 1; for (var dt1 = currentdate.AddDays(15); dt1 <= Enddate; dt1 = dt1.AddDays(15)) { DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = dt1.ToString(); dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; // txtexpirydate.Text = dt1.ToString(); dt.Rows.Add(dr); } dataGridView1.DataSource = dt; } if (cmb_mode_of_service.SelectedItem.ToString() == "Monthly Service") { int year = 0; if (cmb_term_of_service.SelectedItem.ToString() == "One Year") { year = 1; } if (cmb_term_of_service.SelectedItem.ToString() == "Two Year") { year = 2; } if (cmb_term_of_service.SelectedItem.ToString() == "three year") { year = 3; } DateTime currentdate = Convert.ToDateTime(service_start_date.Text); DateTime Enddate = currentdate.AddYears(+year); txtexpirydate.Text = Enddate.ToString(); char c1 = 'A'; int c2 = 1; for (var dt1 = currentdate.AddDays(30); dt1 <= Enddate; dt1 = dt1.AddDays(30)) { DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = dt1.ToString(); dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; // txtexpirydate.Text = dt1.ToString(); dt.Rows.Add(dr); } dataGridView1.DataSource = dt; } if (cmb_mode_of_service.SelectedItem.ToString() == "Trimister Service") { int year = 0; if (cmb_term_of_service.SelectedItem.ToString() == "One Year") { year = 1; } if (cmb_term_of_service.SelectedItem.ToString() == "Two Year") { year = 2; } if (cmb_term_of_service.SelectedItem.ToString() == "three year") { year = 3; } DateTime currentdate = Convert.ToDateTime(service_start_date.Text); DateTime Enddate = currentdate.AddYears(+year); txtexpirydate.Text = Enddate.ToString(); char c1 = 'A'; int c2 = 1; for (var dt1 = currentdate.AddDays(90); dt1 <= Enddate; dt1 = dt1.AddDays(90)) { DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = dt1.ToString(); dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; // txtexpirydate.Text = dt1.ToString(); dt.Rows.Add(dr); } dataGridView1.DataSource = dt; } if (cmb_mode_of_service.SelectedItem.ToString() == "Half Yearly Service") { int year = 0; if (cmb_term_of_service.SelectedItem.ToString() == "One Year") { year = 1; } if (cmb_term_of_service.SelectedItem.ToString() == "Two Year") { year = 2; } if (cmb_term_of_service.SelectedItem.ToString() == "three year") { year = 3; } DateTime currentdate = Convert.ToDateTime(service_start_date.Text); DateTime Enddate = currentdate.AddYears(+year); txtexpirydate.Text = Enddate.ToString(); char c1 = 'A'; int c2 = 1; for (var dt1 = currentdate.AddDays(180); dt1 <= Enddate; dt1 = dt1.AddDays(180)) { DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = dt1.ToString(); dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; // txtexpirydate.Text = dt1.ToString(); dt.Rows.Add(dr); } dataGridView1.DataSource = dt; } if (cmb_mode_of_service.SelectedItem.ToString() == "Yearly Service") { int year = 0; if (cmb_term_of_service.SelectedItem.ToString() == "One Year") { year = 1; } if (cmb_term_of_service.SelectedItem.ToString() == "Two Year") { year = 2; } if (cmb_term_of_service.SelectedItem.ToString() == "three year") { year = 3; } DateTime currentdate = Convert.ToDateTime(service_start_date.Text); DateTime Enddate = currentdate.AddYears(+year); txtexpirydate.Text = Enddate.ToString(); char c1 = 'A'; int c2 = 1; for (var dt1 = currentdate.AddDays(365); dt1 <= Enddate; dt1 = dt1.AddDays(365)) { DataRow dr = dt.NewRow(); dr["SN"] = c2++; dr["serviceid"] = txt_service_id.Text + "-" + c1++; dr["servicedate"] = dt1.ToString(); dr["servicestatus"] = "Pending"; dr["serviceexcutive"] = "Not Alowed"; //txtexpirydate.Text = dt1.ToString(); dt.Rows.Add(dr); } dataGridView1.DataSource = dt; } } }