Encoding.GetBytes Method (String, Int32, Int32, Byte(), Int32)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
When overridden in a derived class, encodes a set of characters from the specified string into the specified byte array.
Assembly: mscorlib (in mscorlib.dll)
'Declaration Public Overridable Function GetBytes ( _ s As String, _ charIndex As Integer, _ charCount As Integer, _ bytes As Byte(), _ byteIndex As Integer _ ) As Integer
Parameters
- s
- Type: System.String
The string containing the set of characters to encode.
- charIndex
- Type: System.Int32
The zero-based index of the first character to encode.
- charCount
- Type: System.Int32
The number of characters to encode.
- bytes
- Type:
System.Byte
()
The byte array to contain the resulting sequence of bytes.
- byteIndex
- Type: System.Int32
The zero-based index at which to start writing the resulting sequence of bytes.
| Exception | Condition |
|---|---|
| ArgumentNullException | s is Nothing. -or- bytes is Nothing. |
| ArgumentOutOfRangeException | charIndex or charCount or byteIndex is less than zero. -or- charIndex and charCount do not denote a valid range in chars. -or- byteIndex is not a valid index in bytes. |
| ArgumentException | bytes does not have enough capacity from byteIndex to the end of the array to accommodate the resulting bytes. |
| EncoderFallbackException | A fallback occurred. |
To calculate the exact array size required by GetBytes to store the resulting bytes, the application should use GetByteCount. To calculate the maximum array size, the application should use GetMaxByteCount. The GetByteCount method generally allocates less memory, while the GetMaxByteCount method generally executes faster.
If the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, the application should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.
For a discussion of programming considerations for use of this method, see the Encoding class description.
The following code example determines the number of bytes required to encode a string or a range in the string, encodes the characters, and displays the resulting bytes.
Imports System.Text Public Class Example Private Shared outputBlock As System.Windows.Controls.TextBlock Public Shared Sub Demo(ByVal outBlock As System.Windows.Controls.TextBlock) outputBlock = outBlock ' The characters to encode: ' Latin Small Letter Z (U+007A) ' Latin Small Letter A (U+0061) ' Combining Breve (U+0306) ' Latin Small Letter AE With Acute (U+01FD) ' Greek Small Letter Beta (U+03B2) ' a high-surrogate value (U+D8FF) ' a low-surrogate value (U+DCFF) Dim myStr As String = "za" & ChrW(&H306) & ChrW(&H1FD) & ChrW(&H3B2) & ChrW(&HD8FF) & ChrW(&HDCFF) ' Get different encodings. Dim u8 As Encoding = Encoding.UTF8 Dim u16LE As Encoding = Encoding.Unicode Dim u16BE As Encoding = Encoding.BigEndianUnicode ' Encode the entire string, and print out the counts and the resulting bytes. outputBlock.Text &= "Encoding the entire string:" & vbCrLf PrintCountsAndBytes(myStr, u8) PrintCountsAndBytes(myStr, u16LE) PrintCountsAndBytes(myStr, u16BE) outputBlock.Text &= vbCrLf ' Encode three characters starting at index 4, and print out the counts and the resulting bytes. outputBlock.Text &= "Encoding the characters from index 4 through 6:" & vbCrLf PrintCountsAndBytes(myStr, 4, 3, u8) PrintCountsAndBytes(myStr, 4, 3, u16LE) PrintCountsAndBytes(myStr, 4, 3, u16BE) End Sub Public Overloads Shared Sub PrintCountsAndBytes(ByVal s As String, ByVal enc As Encoding) ' Display the name of the encoding used. outputBlock.Text += String.Format("{0,-30} :", enc.ToString()) ' Display the exact byte count. Dim iBC As Integer = enc.GetByteCount(s) outputBlock.Text += String.Format(" {0,-3}", iBC) ' Display the maximum byte count. Dim iMBC As Integer = enc.GetMaxByteCount(s.Length) outputBlock.Text += String.Format(" {0,-3} :", iMBC) ' Encode the entire string. Dim bytes As Byte() = enc.GetBytes(s) ' Display all the encoded bytes. PrintHexBytes(bytes) End Sub 'PrintCountsAndBytes Public Overloads Shared Sub PrintCountsAndBytes(ByVal s As String, ByVal index As Integer, ByVal count As Integer, ByVal enc As Encoding) ' Display the name of the encoding used. outputBlock.Text += String.Format("{0,-30} :", enc.ToString()) ' Display the exact byte count. Dim iBC As Integer = enc.GetByteCount(s.ToCharArray(), index, count) outputBlock.Text += String.Format(" {0,-3}", iBC) ' Display the maximum byte count. Dim iMBC As Integer = enc.GetMaxByteCount(count) outputBlock.Text += String.Format(" {0,-3} :", iMBC) ' Encode a range of characters in the string. ' NOTE: In VB.NET, arrays contain one extra element by default. ' The following line creates the array with the exact number of elements required. Dim bytes(iBC - 1) As Byte enc.GetBytes(s, index, count, bytes, bytes.GetLowerBound(0)) ' Display all the encoded bytes. PrintHexBytes(bytes) End Sub Public Shared Sub PrintHexBytes(ByVal bytes() As Byte) If bytes Is Nothing OrElse bytes.Length = 0 Then outputBlock.Text &= "<none>" & vbCrLf Else Dim i As Integer For i = 0 To bytes.Length - 1 outputBlock.Text += String.Format("{0:X2} ", bytes(i)) Next i outputBlock.Text &= vbCrLf End If End Sub End Class ' This example produces the following output. ' Encoding the entire string: ' System.Text.UTF8Encoding : 12 24 :7A 61 CC 86 C7 BD CE B2 F1 8F B3 BF ' System.Text.UnicodeEncoding : 14 16 :7A 00 61 00 06 03 FD 01 B2 03 FF D8 FF DC ' System.Text.UnicodeEncoding : 14 16 :00 7A 00 61 03 06 01 FD 03 B2 D8 FF DC FF ' ' Encoding the characters from index 4 through 6: ' System.Text.UTF8Encoding : 6 12 :CE B2 F1 8F B3 BF ' System.Text.UnicodeEncoding : 6 8 :B2 03 FF D8 FF DC ' System.Text.UnicodeEncoding : 6 8 :03 B2 D8 FF DC FF