If you need to check if a number is an integer, there is no built in function for that in ASP .NET. But you can create a simple method for that like this (code shown in C#).

public static bool IsInteger(string inputValue)
{
if (!IsNumeric(inputValue))
return false;
try
{
int a = Convert.ToInt16(inputValue);    //Convert.ToInt16 will throw exception if string not integer
return true;
}
catch
{
return false;
}
}

public static bool IsNumeric(string inputValue)
{
if (string.Equals(“”, inputValue) || string.Equals(” “, inputValue))
{
return false;
}
else
{
/*
The surrounding ^ and $ characters mean that the expression must appear at the beginning and the end of the string. In real terms, this means that the expression must match the whole string – the string cannot contain any other characters.
*/
string strRegex = @”(^((\+|-)\d)?\d*$)|(^((\+|-)\d)?\d*(\.\d+)?$)”;

Regex re = new Regex(strRegex);
if (re.IsMatch(inputValue))
return (true);
else
return (false);
}
}