can someone help me with saving my data in a file program?
 

I am writing a project that stores vehicle information such as the model,manuf., year, etc.
I have to create a second project that loads the data from the file into memory and loads a drop down combo box with the VIN numbers. When the number is selected from the box, it is supposed to display the appropriate information in labels. Im having problems storing my information and creating this project because the book doesn't explain it very well. Can anyone point me in the right direction?

Re: can someone help me with saving my data in a file program?
 

You didn't mention, how the information is stored. But if you have numbers in your combo box and you can fetch the information with that number, you need to trap SelectedIndexChanged for the combo box:

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged

  ' Get selected VIN number

  Dim ThisVINNumber As Integer



  Try

    ThisVINNumber = CInt(ComboBox1.Items(ComboBox1.SelectedIndex))

    ' Fetch information for this VIN and place it in the labels

  Catch ex As Exception

    ' Handle exception

  End Try



End Sub

Hope this gets you started. If you still have a problem, you need to tell more details about how you store your information (database, a file...)

Re: can someone help me with saving my data in a file program?
 

Since i'm storing my information in a file, do i need to make a .txt file first and then write the program? Also, Since i'm creating two projects under the same thing, how would i go about making my forms? My first idea was to have a form for the user to enter in the data and then have another form that loads that information from the .txt file. I have in mind what I want to do but I just dont know the right way to execute it.

Re: can someone help me with saving my data in a file program?
 

Here is the code that i have so far, but my .txt file won't execute:

Imports System.IO

Public Class createForm



    'Declare module level variables.

    Dim autoStreamWriter As New StreamWriter("Vehicles.txt")





    Private Sub saveButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles saveButton.Click





        If modelTextBox.Text <> "" And manufacturerTextBox.Text <> "" And yearTextBox.Text <> "" And vinNumTextBox.Text <> "" Then

            autoStreamWriter = New StreamWriter("Vehicles.txt", True)

            autoStreamWriter.WriteLine(modelTextBox.Text)

            autoStreamWriter.WriteLine(manufacturerTextBox.Text)

            autoStreamWriter.WriteLine(yearTextBox.Text)

            autoStreamWriter.WriteLine(vinNumTextBox.Text)

            autoStreamWriter.Close()



        Else

            MessageBox.Show("All fields must be entered before the information can be saved.")



            



        End If

        With Me

            autoStreamWriter.WriteLine(modelTextBox.Text)

            autoStreamWriter.WriteLine(manufacturerTextBox.Text)

            autoStreamWriter.WriteLine(yearTextBox.Text)

            autoStreamWriter.WriteLine(vinNumTextBox.Text)

            With .modelTextBox

                .Clear()

                .Focus()



            End With

            .manufacturerTextBox.Clear()

            .yearTextBox.Clear()

            .vinNumTextBox.Clear()



        End With



    End Sub



    Private Sub exitButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exitButton.Click

        'Close the file and the form.



        autoStreamWriter.Close()

        Me.Close()

    End Sub

End Class

Re: can someone help me with saving my data in a file program?
 

I think its a good idea to keep data entry and data viewing as separate forms.

Here's a bit fixing to data entry form (saveButton_Click). Replace control names (TextBox1 <- modelTextBox etc.) and add missing boxes.

' Declare writer

Private autoStreamWriter As StreamWriter

' Set file name as a constant value

Const FileName As String = "C:\Vehicles.txt"



' I use ValidateForm as a separate "form validator"

Private Function ValidateForm() As Boolean

  '

  If TextBox1.Text.Length = 0 Then

    MessageBox.Show("Model is empty. All fields must be entered before the information can be saved.")

    TextBox1.Focus() ' Move focus to missing field

    Return False

  End If

  ' Next Textboxes here

  ' Validation is Ok

  Return True



End Function



' Save button

Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

  '

  ' Check fields

  If Not ValidateForm() Then

    Exit Sub

  End If



  Try

    ' Create writer

    autoStreamWriter = New StreamWriter(FileName, True)

    autoStreamWriter.WriteLine(TextBox1.Text)

    autoStreamWriter.WriteLine(TextBox2.Text)

    ' Add missing WriteLine... here

    autoStreamWriter.Close()

    TextBox1.Clear()

    TextBox2.Clear()

    ' Add missing Clear... here

    ' Set focus to Model box

    TextBox1.Focus()

  Catch ex As Exception

    ' Handle exception

    ' Can't open file etc. can occur, so trap exceptions

  End Try



End Sub

And here's the code to read data. You may create an Auto class object but I used structure and array to hold data. This code goes in your "View data"-form.

' Data reader

Private autoStreamReader As StreamReader

Const FileName As String = "C:\Vehicles.txt"



' Structure to hold information for a one Auto object

Private Structure Auto

  Dim Model As String

  Dim Manufacturer As String

  Dim Year As String

  Dim VIN As Integer ' I did assume VIN is an integer number

End Structure



' Array of Auto objects

Private Autos() As Auto

' Number of items

Private AutoCount As Integer



' This "Read Data"-button

Private Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click

  ' Add similar Try...Catch...End Try here too (file can be missing etc.)

  Dim i As Integer



  ' Set count to -1 (no data)

  AutoCount = -1

  autoStreamReader = New StreamReader(FileName)

  ' Read the whole file

  Do Until autoStreamReader.EndOfStream

    ' Increase counter

    AutoCount += 1

    ' Redim array

    ReDim Preserve Autos(AutoCount)

    ' Read one Auto object

    Autos(AutoCount).Model = autoStreamReader.ReadLine

    Autos(AutoCount).Manufacturer = autoStreamReader.ReadLine

    Autos(AutoCount).Year = autoStreamReader.ReadLine

    Autos(AutoCount).VIN = CInt(autoStreamReader.ReadLine)

  Loop

  ' Fill a combo box with VINs

  For i = 0 To AutoCount

    ComboBox1.Items.Add(Autos(i).VIN)

  Next i

  '

End Sub



' A modified SelectedIndexChanged to select an Auto object and show its data

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged

  ' Get selected Auto object

  Dim ThisAuto As Auto



  Try

    ThisAuto = Autos(ComboBox1.SelectedIndex)

    ' Place information in the labels

    Label1.Text = ThisAuto.Model

    ' and so on...

  Catch ex As Exception

    ' Handle exception

  End Try



End Sub

Hope this gets you started :)

Re: can someone help me with saving my data in a file program?
 

Since i'm using two forms, how would i get the streamwriter to appear first? My plan was to have the createForm (streamwriter) to have a menu strip so that when the user selects like Open Summary or something, the other form will display for the user to go through the records using the vin number combo box

Re: can someone help me with saving my data in a file program?
 

You mean the data entry form is the "main" form? You can set menu item to disabled (Enabled = False).

Or you don't even have to do that. If the user selects "Open Summary" (and the file is empty) the user gets an empty summary form.

Here's a fixed "Read Data"-button, which checks first that the file exists. It also closes the StreamReader, a minor bug in my previous posting:

Private Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click

  '

  Dim i As Integer



  AutoCount = -1

  If Not My.Computer.FileSystem.FileExists(FileName) Then

    Exit Sub

  End If

  Try

    autoStreamReader = New StreamReader(FileName)

    Do Until autoStreamReader.EndOfStream

      AutoCount += 1

      ReDim Preserve Autos(AutoCount)

      Autos(AutoCount).Model = autoStreamReader.ReadLine

      Autos(AutoCount).Manufacturer = autoStreamReader.ReadLine

      Autos(AutoCount).Year = autoStreamReader.ReadLine

      Autos(AutoCount).VIN = CInt(autoStreamReader.ReadLine)

    Loop

  Catch ex As Exception

    ' Handle exception

  Finally

    autoStreamReader.Close()

  End Try

  ' 

  For i = 0 To AutoCount

    ComboBox1.Items.Add(Autos(i).VIN)

  Next i

  '

End Sub