SetLength Method

Stream::SetLength Method (Int64)


When overridden in a derived class, sets the length of the current stream.

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

virtual void SetLength(
	long long value
) abstract


Type: System::Int64

The desired length of the current stream in bytes.

Exception Condition

An I/O error occurs.


The stream does not support both writing and seeking, such as if the stream is constructed from a pipe or console output.


Methods were called after the stream was closed.

If the specified value is less than the current length of the stream, the stream is truncated. If the specified value is larger than the current length of the stream, the stream is expanded. If the stream is expanded, the contents of the stream between the old and the new length are not defined.

A stream must support both writing and seeking for SetLength to work.

Use the CanWrite property to determine whether the current instance supports writing, and the CanSeek property to determine whether seeking is supported.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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