how to sum data table column and get the diffrence

Question

0.00/5 (No votes)

See more:

hello ..
i need to make a data table like that:

Subjects          old        new    diff
Sub_1             10         50     40
Sub_2             30         10     -20
total             40         60     20

this is a part of code

DataTable subjects = new DataTable();
    subjects.Columns.Add("Subjects");
    subjects.Columns.Add("old");
    subjects.Columns.Add("new");
    subjects.Columns.Add("diff");
subjects.Rows.Add("Sub_1", sub1.Old    , sub1.New    , (sub1.New - sub1.Old));
subjects.Rows.Add("Sub_2", sub2.Old    , sub2.New    , (sub2.New - sub2.Old));
subjects.Rows.Add("Total", .. total of above    .. , .. total of above    .., .. total of above  ..);

so i need to ask how to calculate the total value of last column ( Total) , and is there is any other way to calculate the 4th coulmn ( 3rdcol - 2 2nd col )

Posted 14-Feb-15 22:28pm

Dev_Fady...

Add a Solution

1 solution

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)

OriginalGriff · Accepted Answer · 2015-02-14T23:11:00

Adding a calculated column which operates on the totals in the current row is easy: You don't have to do the math yourself, the table can do that for you:

C#

DataTable subjects = new DataTable();
subjects.Columns.Add("Subjects");
subjects.Columns.Add("old", typeof(int));
subjects.Columns.Add("new", typeof(int));
subjects.Columns.Add("diff", typeof(int), "new-old");
subjects.Rows.Add("Sub_1", 50, 60);
subjects.Rows.Add("Sub_2", 100, 46);

But there is no automatic way to generate a totals row AFAIK.
You can do it manually:

C#

subjects.Rows.Add("TOTAL", subjects.Compute("Sum(old)", ""), subjects.Compute("Sum(new)", ""), subjects.Compute("Sum(diff)", ""));

But that won;t update itself automaticaaly - you will have to re-run the Computes each time a cell changes or a row is added / deleted.