BinaryReader.Read Method (Char(), Int32, Int32)

 

Reads the specified number of characters from the stream, starting from a specified point in the character array.

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

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.Int32

The 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 null.

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

Universal Windows Platform
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
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