Question

在C#中，try如何捕获最终阻止工作？

因此，如果有异常，我知道它将跳转到catch块然后跳转到finally块。

但是如果没有错误，catch块就不会运行，但是finally块是否会运行呢？

Answer 1

是的，无论是否存在异常，finally块都会运行。

Try
    [ tryStatements ]
    [ Exit Try ]
[ Catch [ exception [ As type ] ] [ When expression ]
    [ catchStatements ]
    [ Exit Try ] ]
[ Catch ... ]
[ Finally
    [ finallyStatements ] ] --RUN ALWAYS
End Try

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

Answer 2

是的，如果没有异常，则finally子句会被执行。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也会终止执行。

Answer 3

catch的常见用法最后是在try块中获取和使用资源，处理catch块中的异常情况，并释放finally块中的资源。

有关重新抛出异常的更多信息和示例，请参阅try-catch和Throwing Exceptions。有关finally块的更多信息，请参阅try-finally。

public class EHClass
{
    void ReadFile(int index)
    {
        // To run this code, substitute a valid path from your local machine 
        string path = @"c:\users\public\test.txt";
        System.IO.StreamReader file = new System.IO.StreamReader(path);
        char[] buffer = new char[10];
        try
        {
            file.ReadBlock(buffer, index, buffer.Length);
        }
        catch (System.IO.IOException e)
        {
            Console.WriteLine("Error reading from {0}. Message = {1}", path, e.Message);
        }

        finally
        {
            if (file != null)
            {
                file.Close();
            }
        }
        // Do something with buffer...
    }

}

Answer 4

最后阻止总是运行，无论如何。试试这个方法

     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

        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");
        }

Answer 6

是的，最终将始终执行。

即使尝试后没有catch块，finally块仍然会执行。

基本上最终可以用于释放资源，例如文件流，数据库连接和图形处理程序，而无需等待运行时中的垃圾收集器完成该对象。

       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。

最后一个块被执行

其余代码

来源：Exception handling in C# (With try-catch-finally block details)

Answer 7

finally块将始终在方法返回之前执行。

尝试运行以下代码，您会注意到Console.WriteLine("executed")语句中的finally在Console.WriteLine(RunTry())有机会执行之前在何处执行。

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;
    }
    finally
    {
        Console.WriteLine("executed");
    }
    Console.WriteLine("will not be executed since the method already returned");
}

查看结果：

try catch如何最终阻止工作？

7 个答案: