C# testing to see if a string is an integer?

Question

I\'m just curious as to whether there is something built into either the C# language or the .NET Framework that tests to see if something is an integer

if (x         


        

Answer 1

I think that I remember looking at a performance comparison between int.TryParse and int.Parse Regex and char.IsNumber and char.IsNumber was fastest. At any rate, whatever the performance, here's one more way to do it.

        bool isNumeric = true;
        foreach (char c in "12345")
        {
            if (!Char.IsNumber(c))
            {
                isNumeric = false;
                break;
            }
        }

Answer 2

its simple... use this piece of code

bool anyname = your_string_Name.All(char.IsDigit);

it will return true if your string have integer other wise false...

Answer 3

This function will tell you if your string contains ONLY the characters 0123456789.

private bool IsInt(string sVal)
{
    foreach (char c in sVal)
    {
         int iN = (int)c;
         if ((iN > 57) || (iN < 48))
            return false;
    }
    return true;
}

This is different from int.TryParse() which will tell you if your string COULD BE an integer.
eg. " 123\r\n" will return TRUE from int.TryParse() but FALSE from the above function.

...Just depends on the question you need to answer.

Answer 4

If you only want to check whether it's a string or not, you can place the "out int" keywords directly inside a method call. According to dotnetperls.com website, older versions of C# do not allow this syntax. By doing this, you can reduce the line count of the program.

string x = "text or int";
if (int.TryParse(x, out int output))
{
  // Console.WriteLine(x);
  // x is an int
  // Do something
}
else
{
  // x is not an int
}

If you also want to get the int values, you can write like this.

Method 1

string x = "text or int";
int value = 0;
if(int.TryParse(x, out value))
{
  // x is an int
  // Do something
}
  else
{
  // x is not an int
}

Method 2

string x = "text or int";
int num = Convert.ToInt32(x);
Console.WriteLine(num);

Referece: https://www.dotnetperls.com/parse