c# - How to add weeks to a DateTime object

DateTime add weeks

The following asp.net c# example code demonstrate us how can we add one or more weeks with a DateTime object programmatically at run time in an asp.net application. By default, .net framework's DateTime Class have no method or property to add week with a DateTime object. So we need to go technically to add weeks with a date.

We know that one week is equal to 7 days, two weeks is equal to 14 days, three weeks is equal to 21 days and so on. .Net framework's DateTime Class DateTime.AddDays() method allow us to add specified days with a DateTime object. This method require to pass a parameter which hold number of days to add. So, we can use this AddDays() method to add weeks with a DateTime object.

As example, if we want to add one week with a date then we can call the method as DateTime.AddDays(7) and if we want to add three weeks with a DateTime object then we can call the method as DateTime.AddDays(21) and so on. We just need to pass the appropriate number of days as method parameter which represent the number of weeks.

datetime-add-weeks.aspx


<%@ Page Language="C#" AutoEventWireup="true"%>  
    
<!DOCTYPE html>
      
<script runat="server">    
    protected void Button1_Click(object sender, System.EventArgs e)
    {
        //initialize a datetime variable with today
        DateTime today = DateTime.Today;

        //this line added one week (7 days) with today
        DateTime after1week = today.AddDays(7);

        //this line added 3 weeks (21 days) with today
        DateTime after3weeks = today.AddDays(21);

        Label1.Text = "today : " + today.ToLongDateString();

        Label1.Text += "<br /><br />after added one week with today.........<br />";
        Label1.Text += after1week.ToLongDateString();

        Label1.Text += "<br /><br />after added 3 weeks with today.........<br />";
        Label1.Text += after3weeks.ToLongDateString();
    }
</script>      
      
<html xmlns="http://www.w3.org/1999/xhtml">      
<head id="Head1" runat="server">      
    <title>c# example - datetime add weeks</title>      
</head>      
<body>      
    <form id="form1" runat="server">      
    <div>      
        <h2 style="color:MidnightBlue; font-style:italic;">      
            c# example - datetime add weeks
        </h2>      
        <hr width="550" align="left" color="Gainsboro" />      
        <asp:Label       
            ID="Label1"       
            runat="server"      
            Font-Size="X-Large"    
            Font-Names="Comic Sans MS"
            >      
        </asp:Label>      
        <br /><br />    
        <asp:Button       
            ID="Button1"       
            runat="server"       
            Text="add weeks to current date time"      
            OnClick="Button1_Click"    
            Height="40"      
            Font-Bold="true"      
            />      
    </div>      
    </form>      
</body>      
</html>

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