Convert::FromBase64String Method (String^)
Converts the specified string, which encodes binary data as base-64 digits, to an equivalent 8-bit unsigned integer array.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- s
-
Type:
System::String^
The string to convert.
| Exception | Condition |
|---|---|
| ArgumentNullException | s is null. |
| FormatException | The length of s, ignoring white-space characters, is not zero or a multiple of 4. -or- The format of s is invalid. s contains a non-base-64 character, more than two padding characters, or a non-white space-character among the padding characters. |
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 "/".
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 s because all white-space characters are ignored.
The valueless character, "=", is used for trailing padding. The end of s can consist of zero, one, or two padding characters.
Important |
|---|
The FromBase64Stringmethod is designed to process a single string that contains all the data to be decoded. To decode base-64 character data from a stream, use the System.Security.Cryptography::FromBase64Transform class. |
The following example uses the ToBase64String(array<Byte>^) method to convert a byte array to a UUencoded (base-64) string, and then calls the FromBase64String(String^) method to restore the original byte array.
The following is a more complex example that creates a 20-element array of 32-bit integers. It then uses the BitConverter::GetBytes(Int32) method to convert each element into a byte array, which it stores in the appropriate position in a buffer by calling the Array::Copy(Array^, Int32, Array^, Int32, Int32) method. This buffer is then passed to the ToBase64String(array<Byte>^) method to create a UUencoded (base-64) string. It then calls the FromBase64String(String^) method to decode the UUencoded string, and calls the BitConverter::ToInt32 method to convert each set of four bytes (the size of a 32-bit integer) to an integer. The output from the example shows that the original array has been successfully restored.
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
