In C#, how to check whether a string contains an integer?

You could use char.IsDigit:

     bool isIntString = "your string".All(char.IsDigit)

Will return true if the string is a number

    bool containsInt = "your string".Any(char.IsDigit)

Will return true if the string contains a digit

Assuming you want to check that all characters in the string are digits, you could use the Enumerable.All Extension Method with the Char.IsDigit Method as follows:

bool allCharactersInStringAreDigits = myStringVariable.All(char.IsDigit);