What is the best way to save an array of structures in VB.NET?

I have 2 Structures

Public Structure One                    
        Public ItemOne As String
        Public ItemTwo As Integer
    End Structure

    Public Structure Two                   
        Public ItemOne As String
        Public ItemTwo As Integer
        Public ItemThree As Integer
        Public ItemFour As Integer
        Public ItemFive As Integer
    End Structure

Public TestOne(0) as One开发者_Go百科
Public TestTwo(19) as Two

Using the FileOpen, FilePut and FileClose method, I get an error: (Stripped down to only related code as an example)

    Public Sub WriteOne()
                FileOpen(1, "One.dat", OpenMode.Random, OpenAccess.Write)
                FilePut(1, TestOne)
                FileClose(1)
    End Sub

    Public Sub ReadOne()
                FileOpen(1, "One.dat", OpenMode.Random, OpenAccess.Read)
                FileGet(1, TestOne)
                FileClose(1)
    End Sub

    Public Sub WriteTwo()
                FileOpen(1, "Two.dat", OpenMode.Random, OpenAccess.Write)
                FilePut(1, TestTwo)
                FileClose(1)
    End Sub

    Public Sub ReadTwo()
                FileOpen(1, "Two.dat", OpenMode.Random, OpenAccess.Read)
                FileGet(1, TestTwo)
                FileClose(1)
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ReadOne()
        ReadTwo()
        Label1.Text = Cstr(TestOne(0).ItemTwo)
        Label2.Text = Cstr(TestTwo(4).ItemFour)
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TestOne(0).ItemTwo = 9
        TestTwo(4).ItemFour = 78
        WriteOne()
        WriteTwo()
    End Sub

Results In an Unhandled exception. Bad Record Length. and then If I close it and reopen it I get an 'Unable to read beyond end of stream' error.

So what is the best way to save an array of structures? Binary Reader/Writer? and why does this way not work (Even if its derived from VB6)

You can use the serialization BinaryFormatter and save it to a file stream with Serialize, then read it using Deserialize. You'll need to add <Serializable()> to your structure declarations.

<Serializable()> Public Structure Two

...

Dim bf As New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
Dim fStream As New FileStream(filename, FileMode.OpenOrCreate)

bf.Serialize(fStream, TestTwo) ' write to file
fStream.Position = 0 ' reset stream pointer
TestTwo = bf.Deserialize(fStream) ' read from file

I think a better way to save an array of structures is to use serialization. You can use System.Runtime.Serialization.Formatters.Binary.BinaryFormatter, System.Xml.Serialization.XmlSerializer or System.Runtime.Serialization.Formatters.Soap.SoapFormatter to serialize the array.