converting from any base(16, 8, 2) to base 10 in C#

First of all, it is not possible to translate a number from another base without knowing what the base is. You could examine each digit in the string and eliminate the higher base if any digit exceeds the maximum allowed value. The remaining base is the one you would need to work with to translate into decimal. Here is some rough code, part of a much larger program I wrote years ago in QBASIC. You will have to puzzle out the rest for yourself and translate it to C#. An array is declared for each character in the string. The For loop translates each character in the string to base 10 and then concatenates it. DIM B AS INTEGER 'number base DIM R AS INTEGER 'number of digits DIM P AS INTEGER 'place value position starting with 0 DIM S AS DOUBLE 'value of single digit DIM N AS DOUBLE 'decimal value of number R = LEN(digit$) DIM D(R) AS INTEGER FOR P = 0 TO R - 1 S = D(P) * B ^ P N = N + S NEXT P