StreamReader.ReadBlock Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Reads a specified maximum number of characters from the current stream and writes the data to a buffer, beginning at the specified index.

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


Public Overrides Function ReadBlock ( _
    buffer As Char(), _
    index As Integer, _
    count As Integer _
) As Integer
public override int ReadBlock(
    char[] buffer,
    int index,
    int count


  • buffer
    Type: array<System..::.Char>[]()[]
    When this method returns, contains the specified character array with the values between index and (index + count - 1) replaced by the characters read from the current source.

Return Value

Type: System..::.Int32
The number of characters that have been read. The number will be less than or equal to count, depending on whether all input characters have been read.


Exception Condition

buffer is nullNothingnullptra null reference (Nothing in Visual Basic).


The buffer length minus index is less than count.


index or count is negative.


The StreamReader is closed.


An I/O error occurred.


The position of the underlying stream is advanced by the number of characters that were read into buffer.

The method blocks until either count characters are read, or the end of the stream has been reached. This is a blocking version of Read.

Version Information

Windows Phone OS

Supported in: 8.1, 8.0

See Also


StreamReader Class

System.IO Namespace