substring - System.ArgumentOutOfRangeException: 'Index and length must refer to a location within the string. in c#

Question

        string input = "";
        string result = "";
        if (Directory.Exists(Path.GetDirectoryName(filePath)))
        {
            if (File.Exists(filePath))
            {
                input = File.ReadAllText(filePath).ToString();
                List<byte> bList = new List<byte>();
                for (int i = 0; i < input.Length; i += 8)
                {
                    bList.Add(Convert.ToByte(input.Substring(i, 8), 2));
                }
                result = Encoding.UTF8.GetString(bList.ToArray());
                return result;

            }

Exception occurs in Substring inside the for loop Help me to get rid of this exception. Thanks in Advance

Answer 1

You are trying to access a substring without verifying that there are enough characters in the string to do so.

Let's say the file contains 6 characters. That means input.Length is 6. The first iteration of the for loop will make this method call: input.Substring(0, 8). However, the string only has 6 characters in it, so you get an ArgumentOutOfRangeException.