Convert.FromBase64CharArray Method (Char, Int32, Int32)
Converts a subset of a Unicode character array, which encodes binary data as base-64 digits, to an equivalent 8-bit unsigned integer array. Parameters specify the subset in the input array and the number of elements to convert.
Assembly: mscorlib (in mscorlib.dll)
static member FromBase64CharArray : inArray:char * offset:int * length:int -> byte
A Unicode character array.
A position within inArray.
The number of elements in inArray to convert.
Return ValueType: System.Byte
An array of 8-bit unsigned integers equivalent to length elements at position offset in inArray.
inArray is null.
offset or length is less than 0.
offset plus length indicates a position not within inArray.
The length of inArray, ignoring white-space characters, is not zero or a multiple of 4.
The format of inArray is invalid. inArray contains a non-base-64 character, more than two padding characters, or a non-white-space character among the padding characters.
inArray is composed of base-64 digits, white-space characters, and trailing padding characters. The base-64 digits in ascending order from zero are the uppercase characters "A" to "Z", lowercase characters "a" to "z", numerals "0" to "9", and the symbols "+" and "/".
The white-space characters, and their Unicode names and hexadecimal code points, are tab (CHARACTER TABULATION, U+0009), newline (LINE FEED, U+000A), carriage return (CARRIAGE RETURN, U+000D), and blank (SPACE, U+0020). An arbitrary number of white-space characters can appear in inArray because all white-space characters are ignored.
The valueless character, "=", is used for trailing padding. The end of inArray can consist of zero, one, or two padding characters.
The following example demonstrates the use of themethod to decode UUencoded (base-64) data and save it as binary output.
The following example demonstrates the ToBase64CharArray(Byte, Int32, Int32, Char, Int32, Base64FormattingOptions) and methods. The input is divided into groups of three bytes (24 bits) each. Consequently, each group consists of four 6-bit numbers where each number ranges from decimal 0 to 63. In this example, there are 85 3-byte groups with one byte remaining. The first group consists of the hexadecimal values 00, 01, and 02, which yield four 6-bit values equal to decimal 0, 0, 4, and 2. Those four values correspond to the base-64 digits, "A", "A", "E", and "C", at the beginning of the output.
If an integral number of 3-byte groups does not exist, the remaining bytes are effectively padded with zeros to form a complete group. In this example, the value of the last byte is hexadecimal FF. The first 6 bits are equal to decimal 63, which corresponds to the base-64 digit "/" at the end of the output, and the next 2 bits are padded with zeros to yield decimal 48, which corresponds to the base-64 digit, "w". The last two 6-bit values are padding and correspond to the valueless padding character, "=".
Available since 8
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Available since 8.1