BinaryReader.Read Method (Char(), Int32, Int32)
Reads the specified number of characters from the stream, starting from a specified point in the character array.
Assembly: mscorlib (in mscorlib.dll)
'Declaration Public Overridable Function Read ( _ buffer As Char(), _ index As Integer, _ count As Integer _ ) As Integer
Parameters
- buffer
- Type: System.Char()
The buffer to read data into.
- index
- Type: System.Int32
The starting point in the buffer at which to begin reading into the buffer.
- count
- Type: System.Int32
The number of characters to read.
Return Value
Type: System.Int32The total number of characters read into the buffer. This might be less than the number of characters requested if that many characters are not currently available, or it might be zero if the end of the stream is reached.
| Exception | Condition |
|---|---|
| ArgumentException | The buffer length minus index is less than count. -or- The number of decoded characters to read is greater than count. This can happen if a Unicode decoder returns fallback characters or a surrogate pair. |
| ArgumentNullException | buffer is Nothing. |
| ArgumentOutOfRangeException | index or count is negative. |
| ObjectDisposedException | The stream is closed. |
| IOException | An I/O error occurs. |
BinaryReader does not restore the file position after an unsuccessful read operation.
For a list of common I/O tasks, see Common I/O Tasks.
The following example shows how to read and write data using memory as a backing store. This example displays a list of invalid file path characters to the console. Although the code tries to display a list of all invalid file path characters, not all of the characters are within the displayable set of characters. Because the list of invalid characters can vary based on the system, output for this code may also vary.
Imports System Imports System.IO Public Class BinaryRW Shared Sub Main() Dim invalidPathChars() As Char = Path.InvalidPathChars Dim memStream As new MemoryStream() Dim binWriter As New BinaryWriter(memStream) ' Write to memory. binWriter.Write("Invalid file path characters are: ") binWriter.Write(Path.InvalidPathChars, 0, _ Path.InvalidPathChars.Length) ' Create the reader using the same MemoryStream ' as used with the writer. Dim binReader As New BinaryReader(memStream) ' Set Position to the beginning of the stream. memStream.Position = 0 ' Read the data from memory and write it to the console. Console.Write(binReader.ReadString()) Dim upperBound As Integer = _ CInt(memStream.Length - memStream.Position) - 1 Dim memoryData(upperBound) As Char binReader.Read(memoryData, 0, upperBound) Console.WriteLine(memoryData) End Sub End Class
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
