BinaryReader.ReadDouble Method ()

 

Reads an 8-byte floating point value from the current stream and advances the current position of the stream by eight bytes.

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

Public Overridable Function ReadDouble As Double

Return Value

Type: System.Double

An 8-byte floating point value read from the current stream.

Exception Condition
EndOfStreamException

The end of the stream is reached.

ObjectDisposedException

The stream is closed.

IOException

An I/O error occurs.

BinaryReader does not restore the file position after an unsuccessful read.

BinaryReader reads this data type in little-endian format.

For a list of common I/O tasks, see Common I-O Tasks.

The following code example shows how to read and write Double data to memory by using the BinaryReader and BinaryWriter classes on top of the MemoryStream class. MemoryStream only reads and writes Byte data.

Imports System
Imports System.IO

Public Class BinaryRW

    Shared Sub Main()

        Dim i As Integer
        Const upperBound As Integer = 1000

        ' Create random data to write to the stream.
        Dim dataArray(upperBound) As Double
        Dim randomGenerator As New Random()
        For i = 0 To upperBound
            dataArray(i) = 100.1 * randomGenerator.NextDouble()
        Next i

        Dim binWriter As New BinaryWriter(New MemoryStream())
        Try

            ' Write data to the stream.
            Console.WriteLine("Writing data to the stream.")

            For i = 0 To upperBound
                binWriter.Write(dataArray(i))
            Next i

            ' Create a reader using the stream from the writer.
            Dim binReader As New BinaryReader(binWriter.BaseStream)

            ' Return to the beginning of the stream.
            binReader.BaseStream.Position = 0

            ' Read and verify the data.
            Try
                Console.WriteLine("Verifying the written data.")
                For i = 0 To upperBound
                    If binReader.ReadDouble() <> dataArray(i) Then
                        Console.WriteLine("Error writing data.")
                        Exit For
                    End If
                Next i
                Console.WriteLine("The data was written and verified.")
            Catch ex As EndOfStreamException
                Console.WriteLine("Error writing data: {0}.", _
                    ex.GetType().Name)
            End Try
        Finally
            binWriter.Close()
        End Try

    End Sub
End Class

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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