技术文章 > C#正则表达式应用范例

C#正则表达式应用范例

2019-08-25 08:35

文档管理软件,文档管理系统,知识管理系统,档案管理系统的技术资料:
The following example shows the use of Regular Expresssions in C#.This program has basic validation scripts for validation easily useable in all programs.
[code]
csharp
/*

csc /r:System.Text.RegularExpressions.dll,System.dll Validation.cs

*/

using System;
using System.Text.RegularExpressions;

class Validation
{
public static void Main()
{
String strToTest;
Validation objValidate = new Validation();
Console.Write("Enter a String to Test for Alphabets:");
strToTest = Console.ReadLine();
if (objValidate.IsAlpha(strToTest))
{
Console.WriteLine("{0} is Valid Alpha String", strToTest);
}
else
{
Console.WriteLine("{0} is not a Valid Alpha String", strToTest);
}
}
// Function to test for Positive Integers.
public bool IsNaturalNumber(String strNumber)
{
Regex objNotNaturalPattern = new Regex("[^0-9]");
Regex objNaturalPattern = new Regex("0*[1-9][0-9]*");
return !objNotNaturalPattern.IsMatch(strNumber) &&
objNaturalPattern.IsMatch(strNumber);
}
// Function to test for Positive Integers with zero inclusive
public bool IsWholeNumber(String strNumber)
{
Regex objNotWholePattern = new Regex("[^0-9]");
return !objNotWholePattern.IsMatch(strNumber);
}
// Function to Test for Integers both Positive & Negative
public bool IsInteger(String strNumber)
{
Regex objNotIntPattern = new Regex("[^0-9-]");
Regex objIntPattern = new Regex("^-[0-9]+$|^[0-9]+$");
return !objNotIntPattern.IsMatch(strNumber) &&
objIntPattern.IsMatch(strNumber);
}
// Function to Test for Positive Number both Integer & Real
public bool IsPositiveNumber(String strNumber)
{
Regex objNotPositivePattern = new Regex("[^0-9.]");
Regex objPositivePattern = new Regex("^[.][0-9]+$|[0-9]*[.]*[0-9]+$");
Regex objTwoDotPattern = new Regex("[0-9]*[.][0-9]*[.][0-9]*");
return !objNotPositivePattern.IsMatch(strNumber) &&
objPositivePattern.IsMatch(strNumber) &&
!objTwoDotPattern.IsMatch(strNumber);
}
// Function to test whether the string is valid number or not
public bool IsNumber(String strNumber)
{
Regex objNotNumberPattern = new Regex("[^0-9.-]");
Regex objTwoDotPattern = new Regex("[0-9]*[.][0-9]*[.][0-9]*");
Regex objTwoMinusPattern = new Regex("[0-9]*[-][0-9]*[-][0-9]*");
String strValidRealPattern = "^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$";
String strValidIntegerPattern = "^([-]|[0-9])[0-9]*$";
Regex objNumberPattern = new Regex("(" + strValidRealPattern + ")|(" + strValidIntegerPattern + ")");
return !objNotNumberPattern.IsMatch(strNumber) &&
!objTwoDotPattern.IsMatch(strNumber) &&
!objTwoMinusPattern.IsMatch(strNumber) &&
objNumberPattern.IsMatch(strNumber);
}
// Function To test for Alphabets.
public bool IsAlpha(String strToCheck)
{
Regex objAlphaPattern = new Regex("[^a-zA-Z]");
return !objAlphaPattern.IsMatch(strToCheck);
}
// Function to Check for AlphaNumeric.
public bool IsAlphaNumeric(String strToCheck)
{
Regex objAlphaNumericPattern = new Regex("[^a-zA-Z0-9]");
return !objAlphaNumericPattern.IsMatch(strToCheck);
}
}
[/code]
There is another simple way to perform these validation think of it while the next article comes.