IStorageFile2.OpenAsync(FileAccessMode, StorageOpenOptions) Method

Reference

Definition

Namespace:: Windows.Storage

Important

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Edit

Opens a random-access stream over the file.

public:
 IAsyncOperation<IRandomAccessStream ^> ^ OpenAsync(FileAccessMode accessMode, StorageOpenOptions options);

/// [Windows.Foundation.Metadata.Overload("OpenWithOptionsAsync")]
/// [Windows.Foundation.Metadata.RemoteAsync]
IAsyncOperation<IRandomAccessStream> OpenAsync(FileAccessMode const& accessMode, StorageOpenOptions const& options);

[Windows.Foundation.Metadata.Overload("OpenWithOptionsAsync")]
[Windows.Foundation.Metadata.RemoteAsync]
public IAsyncOperation<IRandomAccessStream> OpenAsync(FileAccessMode accessMode, StorageOpenOptions options);

function openAsync(accessMode, options)

Public Function OpenAsync (accessMode As FileAccessMode, options As StorageOpenOptions) As IAsyncOperation(Of IRandomAccessStream)

Parameters

accessMode: FileAccessMode

One of the enumeration values that specifies the type of access to allow.

options: StorageOpenOptions

A bitwise combination of the enumeration values that specify options for opening the stream.

Returns

IAsyncOperation<IRandomAccessStream>

When this method completes, it returns an IRandomAccessStream that contains the requested random-access stream.

Attributes: OverloadAttribute RemoteAsyncAttribute

Remarks

If you simply want to open a file in your app, see the OpenAsync method of the StorageFile class.

Using this method, a file can be accessed by both file readers and writers simultaneously. The following is a table describing the situations for various parameter settings of FileAccessMode and StorageOpenOptions:

	FileAccessMode
StorageOpenOptions	Read	ReadWrite
None	A reader which is lower priority than a writer. If a write occurs, this low priority reader will fail.	This is a single writer. The file cannot be opened if OpenAsync(Read, AllowOnlyReaders) has been used, and it will prevent a new OpenAsync(Read, AllowOnlyReaders) from being used.
AllowOnlyReaders	A reader which can only exist with other readers. If an open is attempted with a writer, it will fail.	This is a single writer. The file cannot be opened if OpenAsync(Read, AllowOnlyReaders) has been used, and it will prevent a new OpenAsync(Read, AllowOnlyReaders) from being used.
AllowReadersAndWriters	A reader which can exist with other readers and writers simultaneously.	This writer will invalidate low priority readers when a write occurs and can coexist with other readers and writers.

Applies to

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