Validation Code

[Silent Sojourner]

If you feed the text from a file, then it's sth. like this:

            Regex regex = new Regex(@"^(\s)*(\d ){6}\d(\s)*$");//note there's a blank space after \d
            bool isValid = true;
            using (StreamReader reader = new StreamReader(File.Open("test.txt", FileMode.Open)))
            {
                while (reader.Peek() > -1)
                {
                    if (regex.IsMatch(reader.ReadLine()) == false)
                    {
                        isValid = false;
                        break;
                    }
                }
                if (isValid)
                {//do sth. ...
                 }
             }

If you already assign the text to a string variable, i.e., sth. like this:
string t = "1 2 3 4 5 6 7\r\n2 4 4 6 7 8 9";
then use string[] ts = t.Split(new string[]{"\r\n"});
to split the string into the array, then use a loop and the above regex to test if each array element matches

This works if you allow "jawed" text, like this:

  1 2 3 4 5 6 7
2 5 3 6 3 6 4
     3 5 6 7 8 9 9

If you don't allow this and want the collumns to strictly align, you need to record the number of white space preceding the first line, and check if the following lines have equal number of preceding white space.