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.NET Framework Class Library
OpenFileDialog..::.OpenFile Method

Opens the file selected by the user, with read-only permission. The file is specified by the FileName property.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Syntax
Public Function OpenFile As Stream
public Stream OpenFile()
public:
Stream^ OpenFile()
member OpenFile : unit -> Stream 

Return Value

Type: System.IO..::.Stream
A Stream that specifies the read-only file selected by the user.
Exceptions
ExceptionCondition
ArgumentNullException

The file name is nullNothingnullptra null reference (Nothing in Visual Basic).

Remarks

The OpenFile method is used to provide a facility to quickly open a file from the dialog box. The file is opened in read-only mode for security purposes. To open a file in read/write mode, you must use another method, such as FileStream.

Examples

The following code example demonstrates how to use the OpenFile method.


    Private Sub button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim myStream As Stream = Nothing
        Dim openFileDialog1 As New OpenFileDialog()

        openFileDialog1.InitialDirectory = "c:\"
        openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
        openFileDialog1.FilterIndex = 2
        openFileDialog1.RestoreDirectory = True

        If openFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
            Try
                myStream = openFileDialog1.OpenFile()
                If (myStream IsNot Nothing) Then
                    ' Insert code to read the stream here.
                End If
            Catch Ex As Exception
                MessageBox.Show("Cannot read file from disk. Original error: " & Ex.Message)
            Finally
                ' Check this again, since we need to make sure we didn't throw an exception on open.
                If (myStream IsNot Nothing) Then
                    myStream.Close()
                End If
            End Try
        End If
    End Sub



private void button1_Click(object sender, System.EventArgs e)
{
    Stream myStream = null;
    OpenFileDialog openFileDialog1 = new OpenFileDialog();

    openFileDialog1.InitialDirectory = "c:\\" ;
    openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*" ;
    openFileDialog1.FilterIndex = 2 ;
    openFileDialog1.RestoreDirectory = true ;

    if(openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        try
        {
            if ((myStream = openFileDialog1.OpenFile()) != null)
            {
                using (myStream)
                {
                    // Insert code to read the stream here.
                }
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
        }
    }
}
    


private:
   void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      Stream^ myStream;
      OpenFileDialog^ openFileDialog1 = gcnew OpenFileDialog;

      openFileDialog1->InitialDirectory = "c:\\";
      openFileDialog1->Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
      openFileDialog1->FilterIndex = 2;
      openFileDialog1->RestoreDirectory = true;

      if ( openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK )
      {
         if ( (myStream = openFileDialog1->OpenFile()) != nullptr )
         {
            // Insert code to read the stream here.
            myStream->Close();
         }
      }
   }

Version Information

.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
.NET Framework Security
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.