C＃getter / setter对

Question

I am trying to create a property i with the following getter and setter. I have tried:

    int i { 
        get{
            return i;   
        }
        set {
            if (value > 60) {
            } else { 
                i = value; 
            } 
        }

    }

However, when I try this I get a stack overflow error when I try to run the code. Is there anything wrong with my code? Any Assistane would be appreciated.

Answer 1

You need a backing field if you have any kind of logic in your property (otherwise automatic properties are the way to go) - currently you are assigning to the property itself which again calls your setter code (likewise for the getter) - that causes the Stackoverflow exception.

Example:

private int _i;
public int SomeProperty
{
  get{ return _i;}
  set 
  {
     //your logic here
     _i = value; 
  }
}

Answer 2

Do this:

private int i; // backing field

int I
{ 
    get
    {
        return i;   
    }
    set
    {
        if (value > 60) {
        } else
        { 
            i = value; 
        } 
    }
}

If you do not do this, your code will be kept in a cyclic state and hence the StackOverflow error.

Answer 3

Its this way

private int i = 0;
public int I
{
    get
    {
        return i;
    }
    set
    {
        if (value > 60)
        {
        }
        else
        {
            i = value;
        }
    }
}

and please follow some coding naming conventions where

1. Property is PascalCase like MyProperty
2. Private Fields are camel Case like localVariable

For More read here

Answer 4

Simply use this piece of code:

int i;

public int I 
{ 
    get { return i; }
    set { if (value <= 60) i = value; } 
}

The problem in your code is that you specified i in the Property which was referring to itself inside the body of getter/setter, turning to be cyclic effect, and eventually StackOverflow error.

Answer 5

int i { 
    get{
        return i;   
    }
    set {
        ...
        i = value; 
        ...
    }
}

In your code above, you are using the same property name inside get and set blocks.

After compilation, your code will be translated to some thing equivalent to this:

int get_i()
{
 return get_i();
}

void set_i(int value)
{
 set_i(value);
}

As you can see each of them will call itself (recursion) infinitely without any exit condition, resulting into a StackOverflow exception.

If you have a backing field to the property, like how other answers to this question have suggested, the compiler would generate some thing equivalent to this, which has no recursion:

int get_i()
{
 return _i; //_i is the backing field
}

void set_i(int value)
{
 _i = value;
}

UPDATE:

For completeness, I am adding here a way to solve your problem.

int _i;
int i { 
    get{
        return _i;   
    }
    set {
        if (value > 60) {
        } else { 
            _i = value; 
        } 
    }
}