Base64FormattingOptions Enumeration


Specifies whether relevant Convert.ToBase64CharArray and Convert.ToBase64String methods insert line breaks in their output.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

Public Enumeration Base64FormattingOptions

Member nameDescription

Inserts line breaks after every 76 characters in the string representation.


Does not insert line breaks after every 76 characters in the string representation.

The Convert.ToBase64CharArray and Convert.ToBase64String methods convert the value of an array of 8-bit unsigned integers to an equivalent string representation that consists of base 64 digits. The string representation can contain one or more line breaks, where a line break is defined as a carriage return character (U+000D) followed by a line feed character (U+000A). Because line breaks are considered whitespace characters in a base-64 encoding, they are ignored when converting a base-64 encoded string back to a byte array. The line breaks are simply convenient when displaying the encoded string to a control or a device such as a console window.

The Base64FormattingOptions.None and Base64FormattingOptions.InsertLineBreaks values are mutually exclusive. Therefore, although the Base64FormattingOptions enumeration is marked with the FlagsAttribute attribute, it makes no sense to perform a bitwise combination of these two values.

The following example calls the Convert.ToBase64String(Byte(), Base64FormattingOptions) with a Base64FormattingOptions.InsertLineBreaks argument to insert line breaks in the string that is produced by encoding a 100-element byte array.

Module Example
   Public Sub Main()
       ' Define a byte array.
       Dim bytes(99) As Byte
       Dim originalTotal As Integer = 0
       For ctr As Integer = 0 To bytes.GetUpperBound(0)
          bytes(ctr) = CByte(ctr + 1)
          originalTotal += bytes(ctr)
       ' Display summary information about the array.
       Console.WriteLine("The original byte array:")
       Console.WriteLine("   Total elements: {0}", bytes.Length)
       Console.WriteLine("   Length of String Representation: {0}",
       Console.WriteLine("   Sum of elements: {0:N0}", originalTotal)                  

       ' Convert the array to a base 64 sring.
       Dim s As String = Convert.ToBase64String(bytes, 
       Console.WriteLine("The base 64 string:{1}   {0}{1}", 
                         s, vbCrLf)

       ' Restore the byte array.
       Dim newBytes() As Byte = Convert.FromBase64String(s)
       Dim newTotal As Integer = 0
       For Each newByte In newBytes
          newTotal += newByte
       ' Display summary information about the restored array.
       Console.WriteLine("   Total elements: {0}", newBytes.Length)
       Console.WriteLine("   Length of String Representation: {0}",
       Console.WriteLine("   Sum of elements: {0:N0}", newTotal)                  
   End Sub
End Module
' The example displays the following output:
'   The original byte array:
'      Total elements: 100
'      Length of String Representation: 299
'      Sum of elements: 5,050
'   The base 64 string:
'      Total elements: 100
'      Length of String Representation: 299
'      Sum of elements: 5,050

As the output from the example shows, the Convert.FromBase64String succeeds in restoring the original byte array; the line break characters are ignored during the conversion.

.NET Framework
Available since 2.0
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