'StackOverflowException was unhandled' errors in C#

Question

I have a problem with my code. I finally got it so there were no errors, but now i have to deal with stackoverflow...

can someone tell me what is wrong with my code?

    public Matrix Projection
    {
        get { return Projection; }
        protected set 
        {
            Projection = value;
            generateFrustum();
        }
    }

It would be nice if you could help!

thanks

More details please... add stack trace and the rest of the code — eyossi, Jun 03 '12 at 13:51
It is a recursive call, Projection calling Projection. Use a private field. Ruben's answer would work. — Shyju, Jun 03 '12 at 13:53
FYI, generateFrustum() should be named GenerateFrustum() according to the .NET guidelines: http://msdn.microsoft.com/en-us/library/ms229002.aspx — Danny Varod, Jun 13 '12 at 15:44
@Nate pay attention to the comments to your questions and select an answer for each. It seems like most of your questions have been voted down due to low quality and you haven't selected a single answer or voted up any answers. — Danny Varod, Jun 21 '12 at 10:00

Ruben · Answer 1 · 2012-06-03T13:54:07.917

23

Your set method calls itself: Projection = value.

private Matrix _projection = null;
public Matrix Projection
{
    get { return _projection; }
    protected set 
    {
        _projection = value;
        generateFrustum();
    }
}

When you use following form:

public Matrix Projection { get; set }

you don't need to specify variable to store actual value, but when you implement get or set explicitly you should declare additional variable and use it in get, set implementations.

edited Jun 03 '12 at 13:54

answered Jun 03 '12 at 13:51

Ruben

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Why did you add a bounty to a (simple) question that some else asked and you answered (correctly)? – Danny Varod Jun 07 '12 at 23:37
Maybe someone will give better answer or more explanation on why there are different behaviours in this two cases (just "get; set" or with implementation of get or set). – Ruben Jun 08 '12 at 05:21
3

public T PropA { get; set; } is sugar syntax for private T _PropA; public T PropA { get { return _PropA; } set { _PropA = value; } } – Danny Varod Jun 08 '12 at 10:48
@DannyVarod Write that in an answer to collect your bounty. – bluevector Jun 13 '12 at 12:55
@jonnyGold Done. Also added additional tips regarding calculations in setter. – Danny Varod Jun 13 '12 at 15:06
@Ruben You've post a bounty. Reasonable answer has been given. What say you? – bluevector Jun 13 '12 at 15:35
@DannyVarod Thank you for answer. Bounty is yours) – Ruben Jun 13 '12 at 19:47
It's the rarest of badges. Congrats. I'm not going to complain about it as long as information was exchanged and questions were answered. – Michael Dorgan Jun 19 '12 at 20:42

score 4 · Answer 2 · edited Jun 03 '12 at 13:54

4

You are defining an infinite recursion on your get and set functions.

get { return Projection; }

is equivalent to:

get { return get();}.

edited Jun 03 '12 at 13:54

Ry-

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answered Jun 03 '12 at 13:53

Samy Arous

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Danny Varod · Answer 3 · 2012-06-13T16:52:51.977

Properties' setters and getters are implemented as methods (get_X and set_X).

Writing Projection = value within the Projection's setter, causes a recursive call to set_Projection() from within set_Projection(). (The same applies to get_Projection().)

Since there is no condition surrounding the call, the recursion is infinite.

As for public T PropA { get; set; }, it is sugar syntax for:

private T _PropA;

public T PropA
{
    get
    {
        return _PropA;
    }
    set
    {
        _PropA = value;
    }
}

What you should do is:

private Matrix _projection;

public Matrix Projection
{
    get
    {
        return _projection;
    }
    protected set 
    {
        // Make sure that Matrix is a structure and not a class
        // override == and != operators in Matrix (and Equals and GetHashCode)
        // If Matrix has to be a class, use !_project.Equals(value) instead

        // Consider using an inaccurate compare here instead of == or Equals
        // so that calculation inaccuracies won't require recalculation

        if (_projection != value)
        {
            _projection = value;
            generateFrustum();
        }
    }
}

score 0 · Answer 4 · answered Jun 13 '12 at 14:24

public T PropA { get; set; }

is actually syntax of

T _PropA; public T PropA { get { return _PropA; } set { _PropA = value; } }

So the answer will be

private Matrix _projection = null;
public Matrix Projection
{
    get { return _projection; }
    protected set 
    {
      _projection = value;
      generateFrustum();
    }
}

you can see read below examples for more info
http://msdn.microsoft.com/en-us/library/ms228503.aspx
http://msdn.microsoft.com/en-us/library/w86s7x04(v=vs.80).aspx

'StackOverflowException was unhandled' errors in C#

4 Answers4