EnumerateNamedStreams Event

Fires when the OS needs to enumerate a file's named streams.

Syntax

• C#
• VB.NET

public event OnEnumerateNamedStreamsHandler OnEnumerateNamedStreams;

public delegate void OnEnumerateNamedStreamsHandler(object sender, CbfsEnumerateNamedStreamsEventArgs e);

public class CbfsEnumerateNamedStreamsEventArgs : EventArgs {
  public string FileName { get; }
  public bool NamedStreamFound { get; set; }
  public string StreamName { get; set; }
  public long StreamSize { get; set; }
  public long StreamAllocationSize { get; set; }
  public long HandleInfo { get; }
  public IntPtr FileContext { get; set; }
  public IntPtr HandleContext { get; set; }
  public IntPtr EnumerationContext { get; set; }
  public int ResultCode { get; set; }
}

Public Event OnEnumerateNamedStreams As OnEnumerateNamedStreamsHandler

Public Delegate Sub OnEnumerateNamedStreamsHandler(sender As Object, e As CbfsEnumerateNamedStreamsEventArgs)

Public Class CbfsEnumerateNamedStreamsEventArgs Inherits EventArgs
  Public ReadOnly Property FileName As String
  Public Property NamedStreamFound As Boolean
  Public Property StreamName As String
  Public Property StreamSize As Long
  Public Property StreamAllocationSize As Long
  Public ReadOnly Property HandleInfo As Long
  Public Property FileContext As IntPtr
  Public Property HandleContext As IntPtr
  Public Property EnumerationContext As IntPtr
  Public Property ResultCode As Integer
End Class

Remarks

This event fires when the OS needs to enumerate the named streams of the file specified by FileName (which will have been opened via OpenFile).

This event only needs to be handled if the UseAlternateDataStreams property is enabled. To handle this event properly, applications must return information about each of the file's named streams. For each named stream, set StreamNameFound to true and supply the named stream's information using the following parameters:

• StreamName: Set to the name of the named stream, prefixed with : (e.g. :MyStreamName). For more information about stream naming conventions, refer to Microsoft's Naming Conventions for Streams information.
  • The length of the returned name must not exceed the value of the MaxFileNameLength property.
• StreamSize: Set the size, in bytes, of the named stream's data.
• StreamAllocationSize: Set to the number of bytes allocated locally for the named stream. This is typically a multiple of the ClusterSize.

If there are no more named streams present, set StreamNameFound to false and leave the above parameters unchanged. When the OS is finished with the named streams enumeration, the CloseNamedStreamsEnumeration event will fire.

The HandleInfo parameter carries a handle to an object with information about the file handle. While within the event handler, it can be used to call any of the following methods: GetHandleCreatorProcessId, GetHandleCreatorProcessName, GetHandleCreatorThreadId, or GetHandleCreatorToken.

The FileContext, HandleContext, and EnumerationContext parameters are placeholders for application-defined data associated with the file, specific handle, and enumeration; respectively. Please refer to the Contexts topic for more information.

The ResultCode parameter will always be 0 when the event is fired. If the event cannot be handled in a "successful" manner for some reason (e.g., a resource isn't available, security checks failed, etc.), set it to a non-zero value to report an appropriate error. Please refer to the Error Reporting and Handling topic for more information.