财产事件 [英] event on a property

问题描述

大家好，
我有一个字符串类型的变量"card_serialNo"；当值更改时，我想执行某些功能.请告知我是否可以对此类型的变量进行值更改事件.
谢谢.

Hi Everybody,
I have a string type variable ''card_serialNo"; I want to perform certain functions when it value get changed. please inform me if I can make a value change event for this type of variable.
thank You.

推荐答案

您可以为此变量创建一个属性并实现INotifyPropertyChanged接口，然后执行此操作. 否则，您可以为此变量创建一个属性，然后从该属性的set块中调用一个方法.

You can create a property for this variable and implement INotifyPropertyChanged interface and do this.
Or else, you can create a property for this variable and call a method from the set block of the property.

如果您仅在类内部需要此方法，则可以创建一个SetCardSerial方法或创建属性并使用设置器.

如果您想要在类之外可以访问的事件，则需要这样的内容:

If you just need this internally in the class, then either create a SetCardSerial method or create a property and use the setter.

If you want an event that is accessible outside the class then you will need something like this:

public class YourClass
{
    public event EventHandler CardSerialNumberChanged;

    private string cardSerialNo;

    public string CardSerialNo
    {
        get
        {
            if (cardSerialNo == null)
                return string.Empty;
            else
                return cardSerialNo;
        }
        set
        {
            if (value == string.Empty)
                value = null;
            if (cardSerialNo != value)
            {
                cardSerialNo = value;
                OnCardSerialNumberChanged(EventArgs.Empty);
            }
        }
    }

    protected virtual void OnCardSerialNumberChanged(EventArgs e)
    {
        EventHandler eh = CardSerialNumberChanged;
        if (eh != null) eh(this, e);
    }
}

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