FileMode Enumeration

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Specifies how the operating system should open a file.

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)

Syntax

Public Enumeration FileMode
public enum FileMode

Members

Member name Description
Append Opens the file if it exists and seeks to the end of the file, or creates a new file. Append can only be used in conjunction with Write. Attempting to seek to a position before the end of the file will throw an IOException and any attempt to read fails and throws an NotSupportedException.
Create Specifies that the operating system should create a new file. If the file already exists, it will be overwritten. Create is equivalent to requesting that if the file does not exist, use CreateNew; otherwise, use Truncate.
CreateNew Specifies that the operating system should create a new file.
Open Specifies that the operating system should open an existing file. The ability to open the file is dependent on the value specified by FileAccess. A System.IO..::.FileNotFoundException is thrown if the file does not exist.
OpenOrCreate Specifies that the operating system should open a file if it exists; otherwise, a new file should be created.
Truncate Specifies that the operating system should open an existing file. Once opened, the file should be truncated so that its size is zero bytes.

Remarks

Specify a FileMode parameter IsolatedStorageFileStream constructors.

FileMode parameters control whether a file is overwritten, created, opened, or some combination thereof. Use Open to open an existing file. To append to a file, use Append. To truncate a file or create a file if it doesn't exist, use Create.

Examples

The following example opens an existing file. This example is part of a larger example provided for the IsolatedStorageFile class.

' Write to an existing file: MyApp1\SubDir1\MyApp1A.txt

' Determine if the file exists before writing to it.
Dim filePath As String = Path.Combine(subdirectory1, "MyApp1A.txt")

If store.FileExists(filePath) Then
    Try
        Using sw As StreamWriter = _
            New StreamWriter(store.OpenFile(filePath, FileMode.Open, FileAccess.Write))

            sw.WriteLine("To do list:")
            sw.WriteLine("1. Buy supplies.")
        End Using

    Catch ex As IsolatedStorageException
        sb.AppendLine(ex.Message)
    End Try
Else
    sb.AppendLine((filePath + "does not exist"))
End If
// Write to an existing file: MyApp1\SubDir1\MyApp1A.txt

// Determine if the file exists before writing to it.
string filePath = Path.Combine(subdirectory1, "MyApp1A.txt");

if (store.FileExists(filePath))
{
    try
    {
        using (StreamWriter sw =
            new StreamWriter(store.OpenFile(filePath,
                FileMode.Open, FileAccess.Write)))
        {
            sw.WriteLine("To do list:");
            sw.WriteLine("1. Buy supplies.");
        }
    }
    catch (IsolatedStorageException ex)
    {

        sb.AppendLine(ex.Message);
    }
}

Version Information

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Platforms

Windows Phone

See Also

Reference

System.IO Namespace

Other Resources

Data for Windows Phone 8