C#判断一个string是否为数字

案一：Try...Catch(执行效率不高)
private bool IsNumberic(string oText)
{
try
{
int var1=Convert.ToInt32 (oText);
return true;
}
catch
{
return false;
}
}

方案二：正则表达式(推荐)
using System.Text.RegularExpressions;
a)
public static bool IsNumeric(string value)
{
return Regex.IsMatch(value, @"^[+-]?\d*[.]?\d*$");
}
public static bool IsInt(string value)
{
return Regex.IsMatch(value, @"^[+-]?\d*$");
}
public static bool IsUnsign(string value)
{
return Regex.IsMatch(value, @"^\d*[.]?\d*$");
}

public static bool isTel(string strInput)
{
return Regex.IsMatch(strInput, @"\d{3}-\d{8}|\d{4}-\d{7}");
}

b)

using System;
using System.Text.RegularExpressions;

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);
}

方案三：遍历
a)
public bool isnumeric(string str)
{
char[] ch=new char[str.Length];
ch=str.ToCharArray();
for(int i=0;i    {
if(ch[i]<48 || ch[i]>57)
return false;
}
return true;
}

b)
public bool IsInteger(string strIn) {
bool bolResult=true;
if(strIn=="") {
bolResult=false;
}
else {
foreach(char Char in strIn) {
if(char.IsNumber(Char))
continue;
else {
bolResult=false;
break;
}
}
}
return bolResult;
}

c)

public static bool isNumeric(string inString)
{
inString=inString.Trim();
bool haveNumber=false;
bool haveDot=false;
for(int i=0;i        {
if (Char.IsNumber(inString[i]))
{
haveNumber=true;
}
else if(inString[i]=='.')
{
if (haveDot)
{
return false;
}
else
{
haveDot=true;
}
}
else if(i==0)
{
if(inString[i]!='+'&&inString[i]!='-')
{
return false;
}
}
else
{
return false;
}
if(i>20)
{
return false;
}
}
return haveNumber;
}