MemoryMappedFile.CreateFromFile Method (FileStream, String, Int64, MemoryMappedFileAccess, MemoryMappedFileSecurity, HandleInheritability, Boolean)
Creates a memory-mapped file that has the specified name, capacity, access type, security permissions, inheritability, and disposal requirement from a file on disk.
Assembly: System.Core (in System.Core.dll)
<SecurityCriticalAttribute> <SecurityPermissionAttribute(SecurityAction.Demand, Flags := SecurityPermissionFlag.UnmanagedCode)> Public Shared Function CreateFromFile ( fileStream As FileStream, mapName As String, capacity As Long, access As MemoryMappedFileAccess, memoryMappedFileSecurity As MemoryMappedFileSecurity, inheritability As HandleInheritability, leaveOpen As Boolean ) As MemoryMappedFile
The fileStream to the file to map.
A name to assign to the memory-mapped file.
The maximum size, in bytes, to allocate to the memory-mapped file. Specify 0 to set the capacity to the size of the file on disk.
One of the enumeration values that specifies the type of access allowed to the memory-mapped file.
This parameter can’t be set to Write.
The permissions that can be granted for file access and operations on memory-mapped files.
This parameter can be null.
One of the enumeration values that specifies whether a handle to the memory-mapped file can be inherited by a child process. The default is None.
Return ValueType: System.IO.MemoryMappedFiles.MemoryMappedFile
A memory-mapped file that has the specified characteristics.
fileStream or mapname is null.
fileStream was closed.
mapName already exists.
If capacity is larger than the size of the file on disk, the file on disk is increased to match the specified capacity even if no data is written to the memory-mapped file. To prevent this from occurring, specify 0 (zero) for the default capacity, which will internally set capacity to the size of the file on disk.
Available since 4.0