try catch finally 块是如何工作的？

Question

在

C#

中，try catch finally 块如何工作？

所以如果有异常，我知道它会跳转到catch块，然后跳转到finally块。

但是如果没有错误，catch 块不会运行，但是finally 块会运行吗？

Answer 1

是的，无论是否有异常，finally 块都会运行。

尝试
    [ 尝试语句 ]
    [退出尝试]
[ Catch [ 异常 [ As 类型 ] ] [ When 表达式 ]
    [ catch 语句 ]
    [退出尝试]]
[ 抓住 ... ]
[ 最后
    [finallyStatements]] --RUN ALWAYS
结束尝试

请参阅：http://msdn.microsoft.com/en-us/library/fk6t46tz%28v=vs.80%29.aspx

Answer 2

finally

块将始终在方法返回之前执行。

尝试运行下面的代码，您会注意到

Console.WriteLine("executed")

语句中的

finally

在

RunTry()

有机会返回之前执行。

static void Main(string[] args)
{
    Console.WriteLine("Hello World!");
    Console.WriteLine(RunTry());
    Console.ReadLine();
}
public static int RunTry()
{
    try
    {
        throw new Exception();
    }
    catch (Exception)
    {
        return 0; // `return` waits and executes only after the `finally` block
    }
    finally
    {
        Console.WriteLine("executed");
    }
    Console.WriteLine("will not be executed since the method already returned");
}

查看结果：

Hello World!
executed
0

Answer 3

是的，如果没有异常，finally 子句就会被执行。 举个例子

     try
        {
            int a = 10;
            int b = 20;
            int z = a + b;
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            Console.WriteLine("Executed");
        }

所以这里如果假设发生异常，finally 也会被执行。

Answer 4

不管怎样，finally 块总是运行。 试试这个方法吧

     public int TryCatchFinally(int a, int b)
    {
        try
        {
            int sum = a + b;
            if (a > b)
            {
                throw new Exception();
            }
            else
            {
                int rightreturn = 2;
                return rightreturn;
            }
        }
        catch (Exception)
        {
            int ret = 1;
            return ret;
        }
        finally
        {
            int fin = 5;
        }
    }

Answer 5

是的，Finally 总是会执行。

即使try之后没有catch块，finally块仍然会执行。

基本上，finally 可以用来释放文件流、数据库连接和图形处理程序等资源，而无需等待运行时的垃圾收集器来完成对象。

       try
        {
            int a = 10;
            int b = 0;
            int x = a / b;
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
        finally
        {
            Console.WriteLine("Finally block is executed");
        }
        Console.WriteLine("Some more code here");

输出：

System.DivideByZeroException：尝试除以零。

最后块被执行

其余代码

来源：C# 中的异常处理（带有 try-catch-finally 块详细信息）

Answer 6

        try
        {
            //Function to Perform
        }
        catch (Exception e)
        {
         //You can display what error occured in Try block, with exact technical spec (DivideByZeroException)
            throw; 
            // Displaying error through signal to Machine, 
            //throw is usefull , if you calling a method with try from derived class.. So the method will directly get the signal                
        }

        finally  //Optional
        {
            //Here You can write any code to be executed after error occured in Try block
            Console.WriteLine("Completed");
        }