HttpResponse.WriteFile Method (String, Int64, Int64) (System.Web)

.NET Framework Class Library

HttpResponse..::.WriteFile Method (String, Int64, Int64)

Writes the specified file directly to an HTTP response output stream.

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

Public Sub WriteFile ( _
	filename As String, _
	offset As Long, _
	size As Long _
)

public void WriteFile(
	string filename,
	long offset,
	long size
)

public:
void WriteFile(
	String^ filename, 
	long long offset, 
	long long size
)

member WriteFile : 
        filename:string * 
        offset:int64 * 
        size:int64 -> unit

Parameters

filename: Type: System..::.String
The name of the file to write to the HTTP output stream.

offset: Type: System..::.Int64
The byte position in the file where writing will start.

size: Type: System..::.Int64
The number of bytes to write to the output stream.

Exceptions

Exception	Condition
HttpException	offset is less than 0. - or - size is greater than the file size minus offset.
ArgumentNullException	The filename parameter is nullNothingnullptra null reference (Nothing in Visual Basic).

Exception

Condition

HttpException

offset is less than 0.

- or -

size is greater than the file size minus offset.

ArgumentNullException

The filename parameter is nullNothingnullptra null reference (Nothing in Visual Basic).

Remarks

When this method is used with large files, calling the method might throw an exception. The size of the file that can be used with this method depends on the hardware configuration of the Web server. For more information, see article 812406, "PRB: Response.WriteFile Cannot Download a Large File" on the Microsoft Knowledge Base Web site.

Examples

The following example writes all the contents of a text file named Login.txt (which might contain literal text and HTML input controls) directly to the output stream.


Dim FileName As String
 Dim MyFileInfo As FileInfo
 Dim StartPos, FileSize As Long

 FileName = "c:\\temp\\login.txt"
 MyFileInfo = New FileInfo(FileName)
 FileSize = MyFileInfo.Length 

 Response.Write("Please Login: <br>")
 Response.WriteFile(FileName, StartPos, FileSize)


String FileName;
 FileInfo MyFileInfo;
 long StartPos = 0, FileSize;

 FileName = "c:\\temp\\login.txt";
 MyFileInfo = new FileInfo(FileName);
 FileSize = MyFileInfo.Length;

 Response.Write("Please Login: <br>");
 Response.WriteFile(FileName, StartPos, FileSize);

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

Reference