CSHARP

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

c# check if string is all numbers

if (str.All(char.IsDigit)) {
  // String only contains numbers
}

c# see if string is int

bool result = int.TryParse("123", out var n);

C# checking if a value is a int

using System;

namespace Help
{
    class Program
    {
        static void Main(string[] args)
        {
            string text1 = "Hello";
            string text2 = "29";

            if (CheckInt(text1) == true) // if text 1 is a int, it's going to print : Text 1 is a int
            {
                Console.WriteLine("Text 1 is a int");
            }
            else if (CheckInt(text2) == true) // if text 2 is a int, which is the case, it's going to print : Text 2 is a int
            {
                Console.WriteLine("Text 2 is a int");
            }
        }
        public static bool CheckInt(string input)
        {
            int number = 0;
            return int.TryParse(input, out number);
        }
    }
}