ReadBlock Method

StreamReader.ReadBlock Method (Char[], Int32, Int32)

.NET Framework 4.6 and 4.5

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 override int ReadBlock(
	char[] buffer,
	int index,
	int count


Type: 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.

Type: System.Int32

The position in buffer at which to begin writing.

Type: System.Int32

The maximum number of characters to read.

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 null.


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.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 4.5
Portable Class Library
Supported in: portable .NET platforms
Available since 5.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
Return to top
© 2015 Microsoft