Question

为什么继承自Exception的类 无法捕获异常

class MyException : Exception
{
private Dictionary<int, string> m_data = new Dictionary<int, string>();
private int index=0;
public int MyIndex
{
set
{
index = value;
}
}
public MyException()
{
m_data.Add(-1, "true");
m_data.Add(1, "找不到指定item");
}
public override string Message
{
get
{
switch (index)
{
case 0: break;
default: return m_data[index];
}
return base.Message;
}
}
}
要如何修改呢？
能给点明显点的提示么？

Answer 1

上面扔出的异常DirectoryNotFoundException不是MyException的子类，不能被catch

能被捕获的前提是：扔出的是catch语句的异常的子类

Answer 2

try
{
File.Create(.....
}
catch(FileNotFoundException ex)
{
throw new MyExceltion{MyIndex=123456789};
}