C#エラーと例外処理の典型例

ユーザーが入力した数値が0-5の中間であるかどうかを確認します:複数catchブロック
 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace ExceptionDemo

{

    class Program

    {

        static void Main(string[] args)

        {

            string userInput;



            while (true)

            {

                try

                {

                    Console.Write("Input a number between 0 and 5" + "(or just hit return to exist)>");

                    userInput = Console.ReadLine();



                    if (userInput == "")

                        break;



                    int index = Convert.ToInt32(userInput);



                    if (index < 0 || index > 5)

                        throw new IndexOutOfRangeException("You typed in  " + userInput);



                    Console.WriteLine("Your number was " + index);

                }

                catch (IndexOutOfRangeException ex)

                {

                    Console.WriteLine("Exception: " + "Number should between 0 and 5." + ex.Message);

                }

                catch (Exception ex)

                {

                    Console.WriteLine("An exception was thrown. Message was: {0}" + ex.Message);

                }

                catch

                {

                    Console.WriteLine("Some other exception has occured");

                }

                finally

                {

                    Console.WriteLine("Thank you");

                }

            }

        }

    }

}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }
0～5以外の数字を入力すると、最初の例外が投げ出され、文字列であれば2番目の例外が投げ出されます.3番目の異常はパラメータを持たず、このcatchブロックは他のC#でプログラミングされていないコードを処理します.
 
次はMSDNのtry...finallyの異常処理です

static void CodeWithCleanup()

        {

            System.IO.FileStream file = null;

            System.IO.FileInfo fileInfo = null;



            try

            {

                fileInfo = new System.IO.FileInfo("C:\\file.txt");



                file = fileInfo.OpenWrite();

                file.WriteByte(0xF);

            }

            catch (System.Exception e)

            {

                System.Console.WriteLine(e.Message);

            }

            finally

            {

                if (file != null)

                {

                    file.Close();

                }

            }

        }

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }