Getting the following edit on a system.dateTime.subtract

Question

1.00/5 (3 votes)

See more:

I am getting this error:

System.DateTime.Subtract(System.DateTime)' is a 'method', which is not valid in the given context

my code is :

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        double age = Math.Round(System.DateTime.Now.Subtract.Tostring(birthDate.Text).TotalDays * 365.25, 2);
        if (age < 21)
            validationResult.Text = "You are under 21.";
        else
            validationResult.Text = "You are 21 or older.";
    }
}

I am relatively new to this. Any idea how to fix?

ok I appreciate the responses i have gotten but honestly that was no help at all. This is code that i have to use. I am supposed to find what is wrong with it and fix it. I was able to fix the other 5 problems but cant figure out how to fix this one. These solutions given will not work for that. I just needed to know how to get rid of this one edit. I tried throwing some () in there but nothing i did worked. I have scoured the text book and internet like crazy. Can someone just tell me the edit is showing on this line:

double age = Math.Round(System.DateTime.Now.Subtract.Tostring(birthDate.Text).TotalDays * 365.25, 2);

can someone just tell me straight forward what to put where. I would really appreciate it.

Posted 25-Oct-14 10:02am

Member 11179919

Updated 26-Oct-14 6:35am

v3

Add a Solution

Comments

[no name] 25-Oct-14 16:36pm

Just what is says. Subtract is a method so you need to throw some () in there.

3 solutions

Solution 4

To get the difference between two dates we can uses the "Subtract" method. It is a parameterised method.Check Here.

Instead of using it like:

Quote:
double age = Math.Round(System.DateTime.Now.Subtract.Tostring(birthDate.Text).TotalDays * 365.25, 2);

use it as:

double age = Math.Round(DateTime.Today.Subtract(new DateTime(1990, 07, 16)).TotalDays / 365.25, 2);

Hope it helps:)

Posted 26-Oct-14 22:13pm

Satya Ranjan Sahoo

Solution 2

I'd suggest to read this tip: Working with Age: it's not the same as a TimeSpan![^]

Posted 25-Oct-14 12:07pm

Maciej Los

Comments

BillWoodruff 25-Oct-14 19:40pm

+5 That's a fascinating article by OG; did you note the very recent comments on problems in the code by eagle-eyed Richard Deeming ?

Note that OG's code does not compute the total age in Months, Days, etc.

Maciej Los 26-Oct-14 5:14am

Thank you, Bill ;)
Yeah, you're right, Richard Deeming is very observant. His new nick should be: Richard "Hawk Eye" Deeming ;)

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

BillWoodruff · Accepted Answer · 2014-10-25T10:59:00

Solution 1

Note that the TimeSpan object gives you several useful properties for determining durations; example:

C#

DateTime now = DateTime.Now;

// note you can use the subtract operator - directly
// and use a negative value with 'AddDays
TimeSpan difference = now - (now.AddDays(-2.4));

// days as a whole number
int diffDays = difference.Days;

// days including fractional value
double totalDays = difference.TotalDays;

int diffHours = difference.Hours;

double totalHours = difference.TotalHours;

Posted 25-Oct-14 10:59am

BillWoodruff

Comments

Maciej Los 25-Oct-14 18:04pm

+5

BillWoodruff 25-Oct-14 19:35pm

Thank you, Maciej

Sergey Alexandrovich Kryukov 26-Oct-14 1:41am

The usage of the API you show is correct, but did you pay attention that difference is always 2.4 days? Why calculating the constant? :-)
—SA

[no name] 26-Oct-14 19:44pm

You got my 5+ on this.