C#string is digit 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# see if string is int
bool result = int.TryParse("123", out var n);