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问题描述:

I want to default value(getter value) to be set for the data property , if the value set by the user does not meet the condition(without private variables).

Here is the code

public class TreeViewModel
{
public a()
{
this.Height = 200;
}
public int Height { get; set ; }
}

If the user sets the value of height lesser that 200 , I want the default value(200) to be set. I tried the following code but not successful as I need to define a body for get (coding in c# MVC)

 public int Height { get; set {
if (value < 200)
value = 200;
} }

网友答案:

Shouldn't it be:

public class TreeViewModel
{
    private const int minHeight = 200;
    private int _Height = minHeight;

    public int Height 
    {
       get { return _Height; }
       set { this._Height = value < minHeight ? minHeight : value; }
    }
}

You may also think of defining the minHeight value externally, e.g. in a config file.

Oh, and yes I used a private variable - the property has no internal way to store a value, so the only other alternative would be to use another persistance medium e.g. Session, ViewState, DataBase etc.

网友答案:

Automatic properties will create a backing field for you under the covers:


public int Height { get; set; }

gets turned into:


public int Height
{
    [CompilerGenerated]
    get
    {
        return this.k__BackingField;
    }
    [CompilerGenerated]
    set
    {
        this.k__BackingField = value;
    }
}

So you'll be fine creating a backing field of your own:


public class TreeViewModel {
    private const int heightDefault = 200;
    private int height = heightDefault;
    public int Height {
        get {
            return this.height;
        }
        set {
            this.height = (value < heightDefault ) ? heightDefault : value;
        }
    }
}

网友答案:

When you use automatic properties, you don't have access to the internal variable itself, so you can't put any logic in there.

You will have to go for a private variable and write the accessors by hand, as pointed out by James.

网友答案:

Automatic properties should be used only when no additional logic is required which is not your case. You'll have to add a backing field. I guess that if you'll search hard enough you'll find some twisted way to do it without a backing field but I would keep it simple and use the old style for the sake of clarity.