加法赋值运算符如何表现

Question

加法赋值运算符在这里如何表现 -

btn.Click += delegate(object sender, EventArgs e)

Answer 1

它将事件处理程序添加到事件 Click。当引发 Click 事件时，将调用添加到其中的所有处理程序方法。

例如：

void BtnClickHandler1(object sender, EventArgs e)
{
    MessageBox.Show("BtnClickHandler1");
}

void BtnClickHandler2(object sender, EventArgs e)
{
    MessageBox.Show("BtnClickHandler2");
}

然后像这样将这些方法添加到 Click 事件中：

btn.Click += BtnClickHandler1
btn.Click += BtnClickHandler2

单击按钮时，将按照您添加它们的顺序调用方法，因此消息框将是：

BtnClickHandler1
BtnClickHandler2

如果您想了解有关 += 运算符的具体信息，MSDN 说：

The += operator is also used to specify a method that will be called in response to an event; such methods are called event handlers. The use of the += operator in this context is referred to as subscribing to an event.

有关详细信息，请查看：

https://msdn.microsoft.com/en-us/library/edzehd2t%28v=vs.110%29.aspx

http://www.dotnetperls.com/event

加法赋值运算符如何表现

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