C#博客第六周

Regular expressions

一.关键概念

1.The result of applying a regular expression to a string is one of the following: To find out whether the string matches the regular expression. To return a substring. To return a new string representing a modification of some part of the original string.

2.System.Text.RegularExpressions namespace is the home of objects associated with regular expressions.

二.运行实例

1.代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
namespace study5
{
class Program
{
static void Main(string[] args)
{
string string1 = "This is a test string"; // find any nonwhitespace followed by whitespa Regex theReg = new Regex(@"(S+)s"); // get the collection of matches MatchCollection theMatches = theReg.Matches(string1); // iterate through the collection foreach (Match theMatch in theMatches) { Console.WriteLine("theMatch.Length: {0}", theMatch.Length); if (theMatch.Length != 0) { Console.WriteLine("theMatch: {0}", theMatch.ToString( )); } }
}
}
}

2.输出结果

theMatch.Length: 5
theMatch: This
theMatch.Length: 3
theMatch: is
theMatch.Length: 2
theMatch: a
theMatch.Length: 5
theMatch: test
请按任意键继续. . .

Exceptions

1.关键字 try catch finally throw

2.示例代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;

namespace study5
{
class Program
{
static void Main(string[] args)
{
try
{
Console.WriteLine("Entering try block...");
throw new System.ApplicationException();
Console.WriteLine("Exiting try block...");
}
catch
{
// Note: simplified example, it is not really solve the exception.
Console.WriteLine("Exception caught and handled.");
}
}

}

}

3.输出结果

System.DivideByZeroException: Msg: Divided 0
在 study5.Program.DoDivide(Double a, Double b) 位置 c:Users史航宇Documents
Visual Studio 2013Projectsstudy5study5Program.cs:行号 32
在 study5.Program.Main(String[] args) 位置 c:Users史航宇DocumentsVisual S
tudio 2013Projectsstudy5study5Program.cs:行号 14
Close file here.
请按任意键继续. . .

Delegates and Events

1.示例代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Timers;
namespace ConsoleApplication5
{
class Program
{
static int counter = 0;
static string displayString = "World,I love you! 世界，我喜欢你! ";
static void Main(string[] args)
{
Timer myTimer = new Timer(100);
myTimer.Elapsed += new ElapsedEventHandler(WriteChar);
myTimer.Start();
Console.ReadKey();

}
static void WriteChar(object source, ElapsedEventArgs e)
{
Console.Write(displayString[counter++ % displayString.Length]);

}
}
}

2.输出结果

World,I love you!
世界，我喜欢你!
（一个字一个字的出现）