Question
You are developing a custom event handler to automatically print all open documents. The event handler helps specify the number of copies to be printed. You need to develop a custom event arguments class to pass as a parameter to the event handler.
Which code segment should you use?
翻译:
你正在开发自动打印所有打开文档的自定义事件程序。事件提供指定打印份数的数量。你需要开发一个自定义事件参数类传递参数给事件。你会用哪段代码?
自己分析:
1、自定义事件参数必须继续自EventArgs
2、必须可以传递打印份数
B和D 首先被选出。在没有对打印份数赋值和取值。所有选B
答案例子参考:C# 自定义事件并使用自定义事件参数方法
A:
public class PrintingArgs
{
private int copies;
public PrintingArgs(int numberOfCopies)
{
this.copies = numberOfCopies;
}
public int Copies
{
get { return this.copies; }
}
}
{
private int copies;
public PrintingArgs(int numberOfCopies)
{
this.copies = numberOfCopies;
}
public int Copies
{
get { return this.copies; }
}
}
B:
public class PrintingArgs : EventArgs
{
private int copies;
public PrintingArgs(int numberOfCopies)
{
this.copies = numberOfCopies;
}
public int Copies
{
get { return this.copies; }
}
}
{
private int copies;
public PrintingArgs(int numberOfCopies)
{
this.copies = numberOfCopies;
}
public int Copies
{
get { return this.copies; }
}
}
C:
public class PrintingArgs
{
private EventArgs eventArgs;
public PrintingArgs(EventArgs ea)
{
this.eventArgs = ea;
}
public EventArgs Args
{
get { return eventArgs; }
}
}
{
private EventArgs eventArgs;
public PrintingArgs(EventArgs ea)
{
this.eventArgs = ea;
}
public EventArgs Args
{
get { return eventArgs; }
}
}
D:
public class PrintingArgs : EventArgs
{
private int copies;
}
{
private int copies;
}