How can declare & initialize a property in the same statement?

Question

This illustrates what I am trying to accomplish:

public class GridModel : PropertyChangedBase
{
    public List<string> LeftValue { get; set; }
    public List<string> LeftValue = new List<string> { "Alpha", "Beta", "Gamma" };
    [...]
}

but I am getting an obvious "identifier repeated" error.

Is there a syntax for that? Perhaps with a constant or fixed List?

dcastro · Answer 1 · 2013-12-01T01:13:51.830

3

You can't initialize a property's backing field when you declare a property.

You'll have to do it in the constructor or simply not use an auto-implemented property, and initialize the backing field directly.

public class GridModel : PropertyChangedBase
{
    private List<string> _leftValue = new List<string> { "Alpha", "Beta", "Gamma" };
    public List<string> LeftValue
    {
        get { return _leftValue; }
        set { _leftvValue = value; }
    }    
}

edited Dec 01 '13 at 01:13

answered Dec 01 '13 at 00:55

dcastro

66,540
21
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You cannot set `_leftvValue` in a setter when declared `readonly`. Either remove the setter or the identifier. – Silvermind Dec 01 '13 at 01:02
Sorry, but shouldn't it also be `new List (new [] { "Alpha", "Beta", "Gamma" });` or `(new [] { "Alpha", "Beta", "Gamma" }).ToList();` – Silvermind Dec 01 '13 at 01:09
1

No, these are called collection initializers. The compiler will create an "Add" call for each item inside brackets: http://msdn.microsoft.com/en-us/library/vstudio/bb384062.aspx – dcastro Dec 01 '13 at 01:13

score 3 · Accepted Answer · answered Dec 01 '13 at 00:56

You can initialize it using backing field:

public class GridModel : PropertyChangedBase
{
    private List<string> leftValue = new List<string> { "Alpha", "Beta", "Gamma" };

    public List<string> LeftValue 
    { 
        get
        {
            return leftValue;
        }
        set
        {
            leftValue = value;
        } 
    }

    [...]
}

score 2 · Answer 3 · answered Dec 01 '13 at 00:56

2

There are some examples at Using Properties (C# Programming Guide), e.g.

private int month = 7;  // Backing store 

public int Month
{
    get
    {
        return month;
    }
}

answered Dec 01 '13 at 00:56

Olaf Dietsche

72,253
8
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How can declare & initialize a property in the same statement?

3 Answers3