How to write isNumber

&
bool IsNumber (string input)
{

try
{
Int.Parse (input);
return true;
}
catch
{
return false;
}

}

&
bool IsNumber(string input)
{
int dotCount=0;
int count=0;
foreach (char c in input)
{
if (dotCount>1)
   return false;
//Check Sign
if (count==0)
   {
   if (c=='+' || c== '-')
      continue;
   } 
if (c=='.')
   {
   dotCount++;
   continue;
   }

if (c>= '0' && c<='9')
   continue;

return false;

}

return true;
}