How can I multiple and sum some properties using Linq

Question

0.00/5 (No votes)

See more:

I has same a problem. which I want caculator score for student. I done:

C#

var cosrse = from ssh in cn.DB.ScoreSheets 
                            where ssh.CourseID == CourseID 
                            select new 
                           { 
                              Student = ssh.Student.LastName +" "+ ssh.Student.FirstName, 
                              ssh.Student.StudentID, Assignment = ssh.Assignment,
                              Project = ssh.Project,
                              ssh.Midterm,
                              ssh.Endterm,
                              ssh.Practice,
                              FinalMatch = ssh.Midterm * 0.2 + ssh.Project * 0.3 + ssh.Endterm * 0.5 //  new a propety FinalMatch 
                           };

I want to add column FinalMatch and assign

C#

ssh.Midterm * 0.2 + ssh.Project * 0.3 + ssh.Endterm * 0.5

, But I don't get any result

Posted 22-Oct-11 22:58pm

williamVu

Add a Solution

2 solutions

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 · Answer 1 · 2011-10-22T23:16:00

Strange! I just knocked together something similar:

C#

private void button1_Click(object sender, EventArgs e)
        {
        List<Student> list = new List<Student>();
        list.Add(new Student(10, 11));
        list.Add(new Student(20, 21));
        list.Add(new Student(30, 31));
        list.Add(new Student(40, 41));
        var c = from s in list
                select new { A = s.A, B = s.B, sum = s.A + s.B };
        foreach (var s in c)
            {
            Console.WriteLine("{0}:{1}+{2}", s.sum, s.A, s.B);
            }
        }
    }
public class Student
    {
    public int A { get; set; }
    public int B { get; set; }
    public Student(int a, int b)
        {
        A = a;
        B = b;
        }
    }

And I get what I would expect:

21:10+11
41:20+21
61:30+31
81:40+41

So when you say: "But I don't get any result" what do you get? Could it be that your ssh.CourseID == CourseID condition is selecting no records?

Bala Selvanayagam · Answer 2 · 2011-10-23T04:14:00

This can happen, if any of your Midterm OR Project OR Endterm is null in the database,

Any mathematical addition involving null will result null, for example 10+null will be Null and that could be the reason you do not get any results (null),

you needs to handled null and make it zero, if it is null in the equation similar to the following query.

C#

var result = from c in db.scoresheets
                        where c.CourseID == 1
                        select new { Mid = c.MidTerm, Last = c.LastTerm, sum1 =( c.MidTerm == null ? 0 : c.MidTerm )+ (c.LastTerm == null ? 0 : c.LastTerm) };

How can I multiple and sum some properties using Linq

2 solutions

Solution 1

Solution 3

Add your solution here

Preview 0