how to check if string input is a number c# code example

Example 1: c# how to check string is number

string s1 = "123";
string s2 = "abc";

bool isNumber = int.TryParse(s1, out int n); // returns true
isNumber = int.TryParse(s2, out int n); // returns false

Example 2: c# how do you check if a string contains only digits

if (str.All(char.IsDigit)) {
  Console.WriteLine("This string only contains numbers");
}