c# - 如何解决 "base64 invalid characters"错误？

Question

当我尝试使用以下代码将 value1 转换为 byte[] 时:

string value1 = "4rdHFh%2BHYoS8oLdVvbUzEVqB8Lvm7kSPnuwF0AAABYQ%3D";
byte[] value2 = Convert.FromBase64String(value1);

Ι 收到一个错误，该字符串包含无效的 base-64 字符...

怎么了？

谢谢!

Answer 1

来自 Convert.FromBase64String

s 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 '/'.

% 不允许出现在 base64 中编码。

查看来自 Wikipedia 的 Base64 索引表

Value   Char
0   A   16  Q   32  g   48  w
1   B   17  R   33  h   49  x
2   C   18  S   34  i   50  y
3   D   19  T   35  j   51  z
4   E   20  U   36  k   52  0
5   F   21  V   37  l   53  1
6   G   22  W   38  m   54  2
7   H   23  X   39  n   55  3
8   I   24  Y   40  o   56  4
9   J   25  Z   41  p   57  5
10  K   26  a   42  q   58  6
11  L   27  b   43  r   59  7
12  M   28  c   44  s   60  8
13  N   29  d   45  t   61  9
14  O   30  e   46  u   62  +
15  P   31  f   47  v   63  /