This documentation is archived and is not being maintained.

HttpResponse.TransmitFile Method (String, Int64, Int64)

Updated: April 2009

Writes the specified part of a file directly to an HTTP response output stream without buffering it in memory.

Namespace:  System.Web
Assembly:  System.Web (in System.Web.dll)

public void TransmitFile(
	string filename,
	long offset,
	long length


Type: System.String

The name of the file to write to the HTTP output.

Type: System.Int64

The position in the file to begin to write to the HTTP output.

Type: System.Int64

The number of bytes to be transmitted.


The offset parameter is less than zero.

- or -

The length parameter is less than -1.

- or -

The length parameter specifies a number of bytes that is greater than the number of bytes the file contains minus the offset.


The out-of-process worker request is not supported.

- or -

The response is not using an HttpWriter object.

If you specify 0 as the offset parameter and -1 as the length parameter, the whole file is sent.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5 SP1, 3.0 SP1, 2.0 SP1




April 2009

Removed comment that incorrectly stated that this is new for the .NET Framework 3.5.

Customer feedback.