#if region does not work

Question

I wanna use a #if statement to skip serializing val when val2 is true and to serialize val when val2 is false. But my code seems not to work:

#if val2
    [XmlIgnore]
#else   
    [XmlElement(ElementName = "val")]
#endif
public bool val
{
    { get; set; } = false;
}

[XmlElement(ElementName = "val2")]
public bool val2
{
    { get; set; } = true;
}

What do I have to do to get it working? Thanks

score 1 · Answer 1 · edited May 23 '17 at 11:59

I think you need to define the symbol you are testing with #define. These are pre-processor directives and you cannot use normal property names etc as those come into play during compilation which happens after pre-processing.

This is from the standard:

Evaluation of a pre-processing expression always yields a boolean value. The rules of evaluation for a pre-processing expression are the same as those for a constant expression (§7.19), except that the only user-defined entities that can be referenced are conditional compilation symbols.

As pointed out in this question, you need something like this:

public class Item
{
    public bool val { get; set; }

    public bool ShouldSerializeval()
    {
       return !val2;
    }

    [XmlElement(ElementName = "val2")]
    public bool val2 { get; set; }  
}

void Main()
{
    Item item = new Item(){val=true, val2=true};

    XmlSerializer xs = new XmlSerializer(typeof(Item));
    StringWriter sw = new StringWriter();
    xs.Serialize(sw, item);
    sw.ToString();
}

but how can I define a value, which shows me, if `val2` is true or false? — Moagggi Stoane, May 30 '15 at 12:43
you can't use `val2` in a pre-processing directive at all. Are you trying to hide `val` if `val2` is true? — NeddySpaghetti, May 30 '15 at 12:47

score 0 · Accepted Answer · answered May 30 '15 at 12:57

0

Just add one of the following to your code, and val won't be serialized, when val2 is true:

public bool ShouldSerializeval()
{
    return val2 == false;
}

or

public bool ShouldSerializeval()
{
    return !val2;
}

answered May 30 '15 at 12:57

cramopy

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#if region does not work

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