想要在开始日期文本框中添加一年的日期（减去一天，然后在结束日期文本框中返回）

Question

I want when I enter date in dd/mm/yyyy in start text box (TxtStartDate), it will automatically fill the end text box (TxtEndDate) by adding one year minus one day in above entered date for example if the user input is '15/04/2014' then the output will comes '14/04/2015' please provide your solution with javascript, jquery or asp.net c#

my HTML Code:

  <tr>
  <td></td>
  <td style="text-align: right"><asp:TextBox ID="TxtEndDate" runat="server"    
  Width="177px" AutoPostBack="True" style="height: 22px"></asp:TextBox>   
  </td>
     <td style="text-align: right">end date</td>
   <td style="text-align: right">
     <asp:TextBox ID="TextStartDate" runat="server" Width="177px"  
      AutoPostBack="True"  style="height: 22px"></asp:TextBox></td>
       <td style="text-align: right; direction: rtl;">
        start date
        </td>
         </tr>

I have two textboxes in my asp.net c# code

Answer 1

For this task, you can take advantage of OnTextChanged event of asp.net textbox controls. To automatically generate the code, you can directly double-click on the txt_Start in the design mode. For this event to be triggered, you will need to add this AutoPostBack="True" to txt_Start Please see the following:

  Start:<asp:TextBox ID="txt_Start" runat="server" AutoPostBack="True" OnTextChanged="txt_Start_TextChanged"></asp:TextBox>
  <asp:Label ID="lbl_wrongdate" runat="server" Text=""></asp:Label>
  <br />
  End: <asp:TextBox ID="txt_End" runat="server"></asp:TextBox>

Then, the logic is very straightforward, I think it is self-explanatory:

    protected void txt_Start_TextChanged(object sender, EventArgs e)
    {
        DateTime start = new DateTime();
        //using System.Globalization;
        if (DateTime.TryParseExact(txt_Start.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out start))
        {
            DateTime end = start.AddYears(1).AddDays(-1);
            txt_End.Text = end.ToString("dd/MM/yyyy");
            lbl_wrongdate.Text = "";
        }
        else
        {
            lbl_wrongdate.Text = "Wrong date format. Allowed formats is dd/mm/yyyy";
            txt_End.Text = "";
        }
    }

After you enter a valid date to txt_Start and press Tab , you will see txt_End is automatically set.

Answer 2

in C#,its simple,can use date.AddYears() and date.Adddays()

first add 1 year by using

Date dtedate = new Date()
dtedate=txtstartdate.Addyears(1)

then substract 1 day by

dtedate1=dtedate.Adddays(-1)

then assign to the control

txtEnddate=dtedate1

hope this helps

updates:

You can simplify the code to a single line.so it the code will be

Date dtedate = new Date()
dtedate=datetime.parse(txtstartdate.text,"dd/MM/yyyy");
txtEnddate.text=convert.tostring(dtedate.AddYears(1).AddDays(-1));