Okay,
I do not have VS2010 installed so rather than upload a project to SkyDrive for demoing here is the code which is VS2010 compatible.
So the demo below shows the basics for read/write class data to and from disk.
Form, three buttons, one DataGridView
''' <summary>
''' For this demo I delete the binary file on startup so we have clean data each time
''' which of course you would not do for a read app.
''' </summary>
''' <remarks></remarks>
Public Class Form1
Private FileName As String = IO.Path.Combine(Application.StartupPath, "KSG.Bin")
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
If IO.File.Exists(FileName) Then
IO.File.Delete(FileName)
End If
DataGridView1.ReadOnly = True
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles cmdSave.Click
Dim List As New AllFiles(FileName)
List.Add(
New AllFile With
{
.Identifier = List.NextIdentifier,
.FileName = "Test1.txt",
.FileDescription = "Test1 demo"
}
)
' Test length constraint on file name
List.Add(
New AllFile With
{
.Identifier = List.NextIdentifier,
.FileName = "1234567890123456",
.FileDescription = "Test2 demo"
}
)
List.Add(
New AllFile With
{
.Identifier = List.NextIdentifier,
.FileName = "Test3.txt",
.FileDescription = "Test3 demo"
}
)
If List.SaveToDataFile Then
MessageBox.Show("Saved")
Else
MessageBox.Show("Not saved")
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles cmdLoad.Click
Dim List As New AllFiles(FileName)
If List.LoadFromDataFile() Then
DataGridView1.DataSource = List.DataTable
For Each col As DataGridViewColumn In DataGridView1.Columns
col.HeaderText = List.DataTable.Columns(col.Name).Caption
Next
End If
End Sub
Private Sub cmdExport_Click(sender As Object, e As EventArgs) Handles cmdFind.Click
If Not IO.File.Exists(FileName) Then
MessageBox.Show("Please create file via the Save button")
End If
Dim List As New AllFiles(FileName)
If List.LoadFromDataFile() Then
Dim Item = List.GetItemByFileName("Test1.txt")
If Item IsNot Nothing Then
MessageBox.Show(Item.ToString)
End If
End If
End Sub
End Class
Class responsible for basics of read/write a binary file. It is not full feature but if you take the time to understand what I did you can complete it. For instance I show read/write, hard coded find, get next primary key value (thinking one user adds items
at any one time). Did not do edits and deletes but you should have no problem if you study the code provided. Also an improvement would be to have changes trigger an event i.e.
property change notification.
Of course feel free to ask for assistance :-)
Imports System.Runtime.Serialization.Formatters.Binary
<Serializable()>
Public Class AllFile
''' <summary>
''' Primary method to identify an item
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks>
''' SEE ALSO NextIdentifier in AllFiles class
''' </remarks>
Public Property Identifier As Int32
Private mFileDescription As String
Public Property FileDescription As String
Set(value As String)
If Not String.IsNullOrWhiteSpace(value) Then
If value.Trim.Length > 42 Then
mFileDescription = value.Trim.Substring(0, 42)
Else
mFileDescription = value
End If
End If
End Set
Get
Return mFileDescription
End Get
End Property
Private mFileName As String
Public Property FileName As String
Set(value As String)
If Not String.IsNullOrWhiteSpace(value) Then
If value.Trim.Length > 15 Then
mFileName = value.Trim.Substring(0, 15)
Else
mFileName = value
End If
End If
End Set
Get
Return mFileName
End Get
End Property
Public Sub New()
End Sub
Public Overrides Function ToString() As String
Return Me.Identifier.ToString & " " & Me.FileName & " " & Me.FileDescription
End Function
End Class
Public Class AllFiles
Inherits CollectionBase
Private mErrors As System.Text.StringBuilder
Public ReadOnly Property Errors As String
Get
Return mErrors.ToString
End Get
End Property
Private mDataFile As String
Public ReadOnly Property DataFile() As String
Get
Return mDataFile
End Get
End Property
Private mDataTable As DataTable
Public ReadOnly Property DataTable As DataTable
Get
mDataTable.Rows.Clear()
If Me.Count > 0 Then
For Each oItem As AllFile In Me.InnerList
mDataTable.Rows.Add(New Object() {oItem.Identifier, oItem.FileName, oItem.FileDescription})
Next
End If
Return mDataTable
End Get
End Property
''' <summary>
'''
''' </summary>
''' <param name="FileName">Name of file to read and write too</param>
''' <remarks></remarks>
Public Sub New(ByVal FileName As String)
MyBase.New()
mDataFile = FileName
mDataTable = New DataTable
mDataTable.Columns.Add(New DataColumn With {.ColumnName = "Identifier", .DataType = GetType(Int32), .Caption = "ID"})
mDataTable.Columns.Add(New DataColumn With {.ColumnName = "FileName", .DataType = GetType(String), .Caption = "Name"})
mDataTable.Columns.Add(New DataColumn With {.ColumnName = "FileDescription", .DataType = GetType(String), .Caption = "Description"})
End Sub
Public Sub Load(ByVal oReader As IDataReader)
While oReader.Read = True
Dim oItem As New AllFile
Me.Add(oItem)
End While
End Sub
Public Function GetItemByFileName(ByVal FileName As String) As AllFile
Return (From T In Me.List.Cast(Of AllFile)() Where T.FileName = FileName).FirstOrDefault
End Function
Public Function GetItemByIdentifier(ByVal Identifier As Int32) As AllFile
Return (From T In Me.List.Cast(Of AllFile)() Where T.Identifier = Identifier).FirstOrDefault
End Function
Public Sub Insert(ByVal iIndex As Integer, ByVal oItem As AllFile)
InnerList.Insert(iIndex, oItem)
End Sub
Public Sub Remove(ByVal oItem As AllFile)
InnerList.Remove(oItem)
End Sub
Public Function Contains(ByVal oItem As AllFile) As Boolean
Return InnerList.Contains(oItem)
End Function
Public Function IndexOf(ByVal oItem As AllFile) As Integer
Return InnerList.IndexOf(oItem)
End Function
Public Function Row(ByVal oItem As AllFile) As Integer
Return Me.IndexOf(oItem)
End Function
Public Function Add(ByVal oItem As AllFile) As Integer
Return InnerList.Add(oItem)
End Function
Public ReadOnly Property NextIdentifier As Int32
Get
If Me.Count = 0 Then
Return 1
Else
Return (From T In Me.InnerList.Cast(Of AllFile)() Select T.Identifier).Max + 1
End If
End Get
End Property
Public Function LoadFromDataFile() As Boolean
Const TheCaller As String = "AllFiles.LoadFromDataFile"
Dim BinF As New BinaryFormatter
Dim obj As Object
Dim oItem As AllFile
If System.IO.File.Exists(DataFile) Then
Try
Dim FS As New System.IO.FileStream(DataFile, IO.FileMode.OpenOrCreate)
Do
obj = BinF.Deserialize(FS)
If obj.GetType Is GetType(AllFile) Then
oItem = CType(obj, AllFile)
Console.WriteLine(oItem.ToString)
Me.Add(oItem)
End If
Loop While FS.Position < FS.Length - 1
FS.Close()
Return True
Catch ioe As System.IO.IOException
Me.mErrors.AppendLine(TheCaller & Environment.NewLine & ioe.Message)
Return False
Catch ex As Exception
Me.mErrors.AppendLine(TheCaller & Environment.NewLine & ex.Message)
Return False
End Try
Else
Return False
End If
End Function
Public Function SaveToDataFile() As Boolean
If Me.Count = 0 Then
Me.mErrors.AppendLine("No items to save")
Return False
End If
Dim BinF As New BinaryFormatter
Try
Dim FS As New System.IO.FileStream(DataFile, IO.FileMode.Create)
For Each oItem As AllFile In Me.InnerList
BinF.Serialize(FS, oItem)
Next
FS.Close()
Return True
Catch ioe As System.IO.IOException
Return False
Catch ex As Exception
Return False
End Try
End Function
End Class
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