vb.net save textbox values for later use - vb.net

I use a textbox in my form to search for words in pdf files. I want to save these search words somewhere for later use. So when the user types a letter in the textbox there will be a pulldown with previous searched words. Something like windows does in Explorer.
Does anyone have an example or is someone familiar with this?

You can store and retrieve a list of search words in an application settings entry of type StringCollection as the data source of the TextBox.AutoCompleteCustomSource property.
Add new entry
Select YourAppName Properties from the Project menu.
Select the Settings tab.
Add new entry in the Name column, say: SearchWords.
From the Type column, select System.Collections.Specialized.StringCollection.
Close the dialog and save.
Retrieve the search words
In the Form's constructor or Load event, say you have a search TextBox named txtSearch:
' +
Imports System.Linq
Imports System.Collections.Specialized
Private Sub YourForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
If My.Settings.SearchWords Is Nothing Then
My.Settings.SearchWords = New StringCollection
End If
Dim acc As New AutoCompleteStringCollection
acc.AddRange(My.Settings.SearchWords.Cast(Of String).ToArray())
txtSearch.AutoCompleteMode = AutoCompleteMode.Suggest
txtSearch.AutoCompleteSource = AutoCompleteSource.CustomSource
txtSearch.AutoCompleteCustomSource = acc
End Sub
Update the collection
You need to add the new words whenever you perform a search:
' When you click a search button...
Private Sub btnSearch_Click(sender As Object, e As EventArgs) Handles btnSearch.Click
AddSearchWord()
End Sub
' If you call the search routine when you press the Enter key...
Private Sub txtSearch_KeyDown(sender As Object, e As KeyEventArgs) Handles txtSearch.KeyDown
If e.KeyCode = Keys.Enter Then
AddSearchWord()
End If
End Sub
' Update the collection...
Private Sub AddSearchWord()
If txtSearch.Text.Trim.Length = 0 Then Return
If Not txtSearch.AutoCompleteCustomSource.Contains(txtSearch.Text) Then
If txtSearch.AutoCompleteCustomSource.Count > 10 Then
txtSearch.AutoCompleteCustomSource.RemoveAt(
txtSearch.AutoCompleteCustomSource.Count - 1)
End If
txtSearch.AutoCompleteCustomSource.Insert(0, txtSearch.Text)
End If
End Sub
Save the collection
Update the SearchWord string collection when you close the Form:
Private Sub YourForm_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
My.Settings.SearchWords = New StringCollection
My.Settings.SearchWords.AddRange(txtSearch.AutoCompleteCustomSource.Cast(Of String).ToArray)
My.Settings.Save()
End Sub
Demo

I found some code Saving text box values to a file to load again that I changed to my needs. It saves the content of my ComboBox1 to a textfile when I click my Submit button. When I load the form the textfile is read and loaded into the ComboBox1 as previous used searches.
'now save the search word to our textfile
PresetName = TextBoxFreeText.Text
If PresetName <> "" Then
TextBoxFreeText.Items.Add(PresetName)
Call SaveData(PresetName)
End If
The code to load the saved values:
Private Sub ReadData()
If My.Computer.FileSystem.FileExists(FilePath) = True Then
myReader = New StreamReader(FilePath)
Dim myText = myReader.ReadLine
While myText IsNot Nothing
listPreset.Add(myText)
myText = myReader.ReadLine
End While
myReader.Close()
'Add Preset Names to ComboBox
If listPreset.Count > 0 Then
Dim PresetName As String
Dim index As Integer
For i = 0 To listPreset.Count - 1
index = listPreset.Item(i).IndexOf(",")
PresetName = Mid(listPreset.Item(i), 1, index)
TextBoxFreeText.Items.Add(PresetName)
Next
End If
End If
End Sub
The code to save the content of ComboBox1
Private Sub SaveData(ByVal PresetName As String)
Dim FileString As String = PresetName & ","
'Build File String
FileString &= TextBoxFreeText.Text & ","
listPreset.Add(FileString)
myWriter = New StreamWriter(FilePath)
For i = 0 To listPreset.Count - 1
myWriter.WriteLine(listPreset.Item(i))
Next
myWriter.Close()
End Sub
There are still two things I want to change. I will ask in a new question.
prevent duplicate search string to be entered in the textfile.
set a maximum to the search string loaded in ComboBox1 (maybe 10 words)

Related

Importing data from text file in VB.NET

So, I am trying to develop a book database. I have created a table with 11 columns which populates a DGV, where only 6 columns are showed. The full data of each book is shown in a lower part of the form, where I have textboxes, which are bounded (BindingSource) to the table, that change as I move in the DGV.
Now, what I want to do is to have the posibility to export/import data from a file.
I have accomplished the exporting part with the following code:
Private Sub BtnExport_Click(sender As Object, e As EventArgs) Handles BtnExport.Click
Dim txt As String = String.Empty
For Each row As DataGridViewRow In DbdocsDataGridView.Rows
For Each cell As DataGridViewCell In row.Cells
'Add the Data rows.
txt += CStr(cell.Value & ","c)
Next
'Add new line.
txt += vbCr & vbLf
Next
Dim folderPath As String = "C:\CSV\"
File.WriteAllText(folderPath & "DataGridViewExport.txt", txt)
End Sub
However, I can't manage to import from the txt. What I've tried is this: https://1bestcsharp.blogspot.com/2018/04/vb.net-import-txt-file-text-to-datagridview.html
It works perfectly if you code the table and it populates de DGV without problem. I can't see how should I adapt that code to my need.
Private Sub BtnImport_Click(sender As Object, e As EventArgs) Handles BtnImport.Click
DbdocsDataGridView.DataSource = table
Dim filas() As String
Dim valores() As String
filas = File.ReadAllLines("C:\CSV\DataGridViewExport.txt")
For i As Integer = 0 To filas.Length - 1 Step +1
valores = filas(i).ToString().Split(",")
Dim row(valores.Length - 1) As String
For j As Integer = 0 To valores.Length - 1 Step +1
row(j) = valores(j).Trim()
Next j
table.Rows.Add(row)
Next i
End Sub
That is what I've tried so far, but I always have an exception arising.
Thanks in advance to anyone who can give me an insight about this.
The DataTable class has built-in methods to load/save data from/to XML called ReadXml and WriteXml. Take a look at example which uses the overload to preserve the schema:
Private ReadOnly dataGridViewExportPath As String = IO.Path.Combine("C:\", "CSV", "DataGridViewExport.txt")
Private Sub BtnExport_Click(sender As Object, e As EventArgs) Handles BtnExport.Click
table.WriteXml(path, XmlWriteMode.WriteSchema)
End Sub
Private Sub BtnImport_Click(sender As Object, e As EventArgs) Handles BtnImport.Click
table.ReadXml(path)
End Sub
While users can manually edit the XML file that is generated from WriteXML, I would certainly not suggest it.
This is code which writes to a text file:
speichern means to save.
Note that I use a # in my example for formatting reasons. When reading in again, you can find the # and then you know that and that line is coming...
And I used Private ReadOnly Deu As New System.Globalization.CultureInfo("de-DE") to format the Date into German format, but you can decide yourself if you want that. 🙂
Note that I'm using a FileDialog that I downloaded from Visual Studio's own NuGet package manager.
Private Sub Button_speichern_Click(sender As Object, e As EventArgs) Handles Button_speichern.Click
speichern()
End Sub
Private Sub speichern()
'-------------------------------------------------------------------------------------------------------------
' User can choose where to save the text file and the program will save it .
'-------------------------------------------------------------------------------------------------------------
Dim Path As String
Using SFD1 As New CommonSaveFileDialog
SFD1.Title = "store data in a text file"
SFD1.Filters.Add(New CommonFileDialogFilter("Textdatei", ".txt"))
SFD1.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
If SFD1.ShowDialog() = CommonFileDialogResult.Ok Then
Path = SFD1.FileName & ".txt"
Else
Return
End If
End Using
Using textfile As System.IO.StreamWriter = My.Computer.FileSystem.OpenTextFileWriter(Path, True, System.Text.Encoding.UTF8)
textfile.WriteLine("Timestamp of this file [dd.mm.yyyy hh:mm:ss]: " & Date.Now.ToString("G", Deu) & NewLine & NewLine) 'supposed to be line break + 2 blank lines :-)
textfile.WriteLine("your text")
textfile.WriteLine("#") 'Marker
textfile.Close()
End Using
End Sub
Private Sub FormMain_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
speichern()
End Sub
And this is to read from a text file:
'read all Text
Dim RAT() As String = System.IO.File.ReadAllLines(Pfad, System.Text.Encoding.UTF8)
If RAT.Length = 0 Then Return Nothing
For i As Integer = 0 To RAT.Length - 1 Step 1
If RAT(i) = "#" OrElse RAT(i) = "" Then Continue For
'do your work here with (RAT(i))
Next

Read and write below a precise cell in a CSV

I'm stuck on a basic problem. What I want is to parse through a CSV in order to compare some string and write below if I find it.
Precisely, I have a programe where I can drag and drop some button, when I drop this button I want to save it's new location on the first empty cells below the corresponding column.
Here's a sample of my CSV :
So I substring the .x/.y from my CSV and compare the name from the drop button with each cell with the help of textFieldParser. It seems to work my loop stopped when it find an equal expression.
But here's the problem I don't know how to say to my program to write below it. The first reason I can figured it out is because my parser go until the endOfData and I want it to go until the endOfDat + one row.
The second one is because I don't know if I can use a fieldwriter into textFieldParser, I mean I tried to create a variable with row+1 and write below but nothing happen when I use fileWriter.
now a sample of my code :
Private Sub manageCsv(ByVal sender As Button)
Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser("..\..\Pic\csvPic.csv")
MyReader.TextFieldType = FileIO.FieldType.Delimited
MyReader.SetDelimiters(",")
Dim currentRow As String()
Dim rowPlusOne As String()
While Not MyReader.EndOfData
Try
currentRow = MyReader.ReadFields()
rowPlusUn = MyReader.ReadFields()
Dim currentField As String
Dim str As String = btnSender.Name.Substring(3)
Dim nameDelimited As String
Dim x As Integer
For Each currentField In currentRow
''Search the corresponding field''
x = InStr(currentField, ".")
If Not (currentField.Equals("imagefile")) Then ''imagefile is the first index of my csv''
nameDelimited = currentField.Substring(0, x) ''substr the extension''
If nameDelimited.Equals(str) Then
writeCsv("..\..\Image\csvPic.csv", nameDelimited, ",")
''Ofc the "+1" does not work but that was the idea''
currentRow(+1) = lblImgName.Text
currentRow(+1) = btnSender.Location.ToString
Exit For
End If
End If
Next
Catch ex As _
Microsoft.VisualBasic.FileIO.MalformedLineException
MsgBox("Line " & ex.Message & "is not valid and will be skipped.")
End Try
End While
End Using
End Sub
I hope it's clear enough, if not i'll try to elaborate more. Thanks for your help
Show your teacher that there are better ways to do this with a simple text file. The file will only exist if buttons have been moved before in the application. See in line comments.
Private ButtonLocation As New Dictionary(Of Button, Point)
Private MouseIsDown As Boolean
Private ptX, ptY As Integer 'Starting point of mouse relative to the button
Private btn As Button 'The button being moved
Private ButtonPath As String = "C:\Users\maryo\Desktop\Code\DroppedButtons.txt"
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'Reposition the buttons to where they were dropped in the previous session.
If File.Exists(ButtonPath) Then
Dim lines = File.ReadAllLines(ButtonPath) 'returns an array of strings (each line)
For Each line In lines 'loop though each line in the file
Dim fields = line.Split(","c) 'The three values on the line are separated by a comma
Dim b = DirectCast(Controls(fields(0)), Button) 'Change the string Button.Name
'to an actual Button object by finding it in the controls collection
'Set the location with the next 2 values on the line
b.Location = New Point(CInt(fields(1)), CInt(fields(2)))
'Add the Button and Location to the list
ButtonLocation.Add(b, b.Location)
Next
End If
End Sub
'These three Event procedures are the normal code to Drag and Drop a control
Private Sub Button_MouseDown(sender As Object, e As MouseEventArgs) Handles Button1.MouseDown, Button2.MouseDown
btn = DirectCast(sender, Button)
ptX = e.Location.X
ptY = e.Location.Y
MouseIsDown = True
End Sub
Private Sub Button_MouseMove(sender As Object, e As MouseEventArgs) Handles Button1.MouseMove, Button2.MouseMove
If MouseIsDown Then
'e.X and e.Y are the coordinates of the Mouse relative to the control (the Button)
'not the Form or the Screen.
btn.Location = New Point(btn.Location.X + e.X - ptX, btn.Location.Y + e.Y - ptY)
End If
End Sub
Private Sub Button_MouseUp(sender As Object, e As MouseEventArgs) Handles Button1.MouseUp, Button2.MouseUp
MouseIsDown = False
'When we drop the button with the MouseUp event we record the new location in the list
RecordButtonLocation(btn, btn.Location)
btn = Nothing
End Sub
Private Sub RecordButtonLocation(Sender As Button, Location As Point)
'Check if the Button is already in the list
If ButtonLocation.ContainsKey(Sender) Then
'Record its new location
ButtonLocation.Item(Sender) = Location
Else
'If it is not in the list add it.
ButtonLocation.Add(Sender, Location)
End If
End Sub
Private Sub Form1_Closing(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles Me.Closing
SaveDictionary()
End Sub
Private Sub SaveDictionary()
If ButtonLocation.Count > 0 Then
'If there is anything in the list we will create or overwrite the file
Dim sb As New StringBuilder
For Each kv As KeyValuePair(Of Button, Point) In ButtonLocation
sb.AppendLine($"{kv.Key.Name},{kv.Value.X},{kv.Value.Y}")
Next
File.WriteAllText(ButtonPath, sb.ToString)
End If
End Sub

vb.NET You are not allowed to perform an operation across different threads

I am running code to read text from pdf files and than create a WordCloud. To inform the user the process is on going I add a BackgroundWorker to my form that shows an image saying Loading. I get an error for operating across different threads.
Private Sub ButtonCreate_Click(sender As Object, e As EventArgs) Handles ButtonCreate.Click
bTextEmpty = False
ListView1.Items.Clear()
ResultPictureBox.Image = Nothing
If ListBox1.SelectedIndex > -1 Then
For Each Item As Object In ListBox1.SelectedItems
Dim ItemSelected = CType(Item("Path"), String)
Dim myTempFile As Boolean = File.Exists(ItemSelected + "\Words.txt")
If myTempFile = False Then
'when we load the form we first call the code to count words in all files in a directory
'lets check if the folder exists
If (Not System.IO.Directory.Exists(ItemSelected)) Then
Dim unused = MsgBox("The archive " + ItemSelected.Substring(ItemSelected.Length - 5, Length) + " was not found",, Title)
Exit Sub
Else
Call CreateWordList(ItemSelected)
End If
End If
'if the words file is empty we cant create a cloud so exit the sub
If bTextEmpty = True Then Exit Sub
'then we fill the wordcloud and Listview from the created textfile
Call CreateMyCloud(ItemSelected + "\Words.txt")
Next
Else
Dim unused = MsgBox("You have to choose an Archive to create the Word Cloud",, Title)
End If
Size = New Drawing.Size(1400, 800)
End Sub
I put above code in a Private Sub and called it from my BackgroundWorker. The error occured at this line: If ListBox1.SelectedIndex > -1 Then
After trying the suggested code I get the same error again:
Public Sub CreateMyCloud(ByVal sourcePDF As String)
Dim WordsFreqList As New List(Of WordsFrequencies)
For Each line As String In File.ReadLines(sourcePDF)
Dim splitText As String() = line.Split(","c)
If splitText IsNot Nothing AndAlso splitText.Length = 2 Then
Dim wordFrq As New WordsFrequencies
Dim freq As Integer
wordFrq.Word = splitText(0)
wordFrq.Frequency = If(Integer.TryParse(splitText(1), freq), freq, 0)
WordsFreqList.Add(wordFrq)
End If
Next
If WordsFreqList.Count > 0 Then
' Order the list based on the Frequency
WordsFreqList = WordsFreqList.OrderByDescending(Function(w) w.Frequency).ToList
' Add the sorted items to the listview
WordsFreqList.ForEach(Sub(wf)
error -> ListView1.Items.Add(New ListViewItem(New String() {wf.Word, wf.Frequency.ToString}, 0))
End Sub)
End If
Dim wc As WordCloudGen = New WordCloudGen(600, 400)
Dim i As Image = wc.Draw(WordsFreqList.Select(Function(wf) wf.Word).ToList, WordsFreqList.Select(Function(wf) wf.Frequency).ToList)
ResultPictureBox.Image = i
End Sub
Should look something more like:
Private Sub ButtonCreate_Click(sender As Object, e As EventArgs) Handles ButtonCreate.Click
If ListBox1.SelectedItems.Count > 0 Then
Dim data As New List(Of Object)
For Each Item As Object In ListBox1.SelectedItems
data.Add(Item)
Next
bTextEmpty = False
ListView1.Items.Clear()
ResultPictureBox.Image = Nothing
BackgroundWorker1.RunWorkerAsync(data)
Else
MessageBox.Show("You have to choose an Archive to create the Word Cloud",, Title)
End If
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim data As List(Of Object) = DirectCast(e.Argument, List(Of Object))
For Each Item As Object In data
Dim ItemSelected = CType(Item("Path"), String)
Dim myTempFile As Boolean = File.Exists(ItemSelected + "\Words.txt")
If myTempFile = False Then
'when we load the form we first call the code to count words in all files in a directory
'lets check if the folder exists
If (Not System.IO.Directory.Exists(ItemSelected)) Then
MessageBox.Show("The archive " + ItemSelected.Substring(ItemSelected.Length - 5, Length) + " was not found",, Title)
Exit Sub
Else
Call CreateWordList(ItemSelected)
End If
End If
'if the words file is empty we cant create a cloud so exit the sub
If bTextEmpty = True Then Exit Sub
'then we fill the wordcloud and Listview from the created textfile
Call CreateMyCloud(ItemSelected + "\Words.txt")
Next
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
Size = New Drawing.Size(1400, 800)
End Sub
To fix the error in your second, edited post:
WordsFreqList.ForEach(Sub(wf)
ListView1.Invoke(Sub()
ListView1.Items.Add(New ListViewItem(New String() {wf.Word, wf.Frequency.ToString}, 0))
End Sub)
End Sub)
You cannot simply access controls outside of the current thread. You first need to call the Invoke method on the target control and then pass a delegate containing the instructions intended to modify the control outside of the current thread. See this article on MSDN on how to do this: https://learn.microsoft.com/en-us/dotnet/desktop/winforms/controls/how-to-make-thread-safe-calls-to-windows-forms-controls?view=netframeworkdesktop-4.8

VB.Net populating text boxes from text file

I'm creating an inventory management system where the data is stored in a text file. I'm able to save data to the text file, however on the tracker screen it should show current inventory such as: Manufacturer, Processor, Video, Form, RAM, etc. However, all my text boxes remain blank and I'm not sure why. It's not reading properly or updating the text.
frmTracker.vb
Private Sub txtManufacturer_TextChanged(sender As Object, e As EventArgs) Handles txtManufacturer.TextChanged
Dim objMyStreamReader = System.IO.File.OpenText("inventory.txt")
Dim strInventory = objMyStreamReader.ReadLine()
objMyStreamReader.Close()
txtManufacturer.AppendText(strInventory)
End Sub
This is how I'm currently saving the data to the text file.
frmItemEntry.vb
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
Dim objMyStreamReader As System.IO.StreamReader
Dim objMyStreamWriter As System.IO.StreamWriter = System.IO.File.CreateText("inventory.txt")
Dim strInventory As String
objMyStreamWriter.WriteLine(txtManufacturerEntry.Text)
objMyStreamWriter.WriteLine(txtProcessorEntry.Text)
objMyStreamWriter.WriteLine(txtVideoEntry.Text)
objMyStreamWriter.WriteLine(txtFormEntry.Text)
objMyStreamWriter.WriteLine(txtRamEntry.Text)
objMyStreamWriter.WriteLine(txtVramEntry.Text)
objMyStreamWriter.WriteLine(txtHdEntry.Text)
objMyStreamWriter.WriteLine(chkWirelessEntry.CheckState)
objMyStreamWriter.Close()
Me.Close()
End Sub
Example from inventory.txt
Dell
i5
Nvidia
Desktop
8
4
600
0
To be honest, controls should never be used as the primary store for your data in a program. You should really be creating a class and a list of that class to store your data.
You can then read your data into the list from your file, and then, display it from there in your form.
There are several ways of navigating through the data and saving updates. The suggestion below uses buttons for next item and previous item, and a button to save update the file.
It's all pretty self explanatory, but if there's something your not sure about, please have a google and learn something new :-D
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ReadDataFile()
DisplayItem(0)
End Sub
Private Class InventoryItem
Public Property Manufacturer As String
Public Property Processor As String
Public Property Video As String
Public Property FormFactor As String
Public Property Ram As String
Public Property VRam As String
Public Property Hd As String
Public Property Wireless As CheckState
Public Sub New()
Manufacturer = ""
Processor = ""
Video = ""
FormFactor = ""
Ram = ""
VRam = ""
Hd = ""
Wireless = CheckState.Unchecked
End Sub
End Class
Dim Inventory As New List(Of InventoryItem)
Dim currentItemIndex As Integer
Private Sub ReadDataFile()
Using objMyStreamReader As New StreamReader("k:\inventory.txt")
Do Until objMyStreamReader.EndOfStream
Dim newItem As New InventoryItem
newItem.Manufacturer = objMyStreamReader.ReadLine()
newItem.Processor = objMyStreamReader.ReadLine()
newItem.Video = objMyStreamReader.ReadLine()
newItem.FormFactor = objMyStreamReader.ReadLine()
newItem.Ram = objMyStreamReader.ReadLine()
newItem.VRam = objMyStreamReader.ReadLine()
newItem.Hd = objMyStreamReader.ReadLine()
Dim wirelessValue As String = objMyStreamReader.ReadLine()
If wirelessValue = "0" Then
newItem.Wireless = CheckState.Unchecked
ElseIf wirelessValue = "1" Then
newItem.Wireless = CheckState.Checked
End If
Inventory.Add(newItem)
Loop
End Using
End Sub
Private Sub SaveDataFile()
Using objMyStreamWriter As New System.IO.StreamWriter("k:\inventory.txt", False)
For Each item As InventoryItem In Inventory
objMyStreamWriter.WriteLine(item.Manufacturer)
objMyStreamWriter.WriteLine(item.Processor)
objMyStreamWriter.WriteLine(item.Video)
objMyStreamWriter.WriteLine(item.FormFactor)
objMyStreamWriter.WriteLine(item.Ram)
objMyStreamWriter.WriteLine(item.VRam)
objMyStreamWriter.WriteLine(item.Hd)
If item.Wireless = CheckState.Checked Then
objMyStreamWriter.WriteLine("1")
Else
objMyStreamWriter.WriteLine(0)
End If
Next
End Using
End Sub
Private Sub DisplayItem(index As Integer)
With Inventory(index)
txtManufacturerEntry.Text = .Manufacturer
txtProcessorEntry.Text = .Processor
txtVideoEntry.Text = .Video
txtFormEntry.Text = .FormFactor
txtRamEntry.Text = .Ram
txtVramEntry.Text = .VRam
txtHdEntry.Text = .Hd
chkWirelessEntry.CheckState = .Wireless
End With
End Sub
Private Sub BtnUpdateItem_Click(sender As Object, e As EventArgs) Handles BtnUpdateItem.Click
With Inventory(currentItemIndex)
.Manufacturer = txtManufacturerEntry.Text
.Processor = txtProcessorEntry.Text
.Video = txtVideoEntry.Text
.FormFactor = txtFormEntry.Text
.Ram = txtRamEntry.Text
.VRam = txtVramEntry.Text
.Hd = txtHdEntry.Text
.Wireless = chkWirelessEntry.CheckState
End With
SaveDataFile()
End Sub
Private Sub BtnPreviousItem_Click(sender As Object, e As EventArgs) Handles BtnPreviousItem.Click
If currentItemIndex > 0 Then
currentItemIndex -= 1
DisplayItem(currentItemIndex)
End If
End Sub
Private Sub BtnNextItem_Click(sender As Object, e As EventArgs) Handles BtnNextItem.Click
If currentItemIndex < Inventory.Count - 1 Then
currentItemIndex -= 1
DisplayItem(currentItemIndex)
End If
End Sub
First change the format of your text file.
Dell,i5,Nvidia,Desktop,8,2,600,True
Acer,i7,Intel,Desktop,16,4,1GB,True
HP,Pentium,Diamond Viper,Desktop,4,2,200,False
Surface Pro,i7,Intel,Laptop,8,2,500,True
Each line is a record and each field in the record is separated by a comma (no spaces so we don't have to .Trim in code) (a space within a field is fine, notice Surface Pro).
Now it is easier to read the file in code.
This solution uses a BindingSource and DataBindings. This simplifies Navigation and editing and saving the data.
Public Class Form5
Private bs As BindingSource
Private dt As New DataTable
#Region "Set Up the Form"
Private Sub Form5_Load(sender As Object, e As EventArgs) Handles MyBase.Load
AddColumnsToDataTable()
FillDataTable()
AddDataBindings()
End Sub
Private Sub AddColumnsToDataTable()
'Prepare the DataTable to hold data
dt.Columns.Add("Manufacturer", GetType(String))
dt.Columns.Add("Processor", GetType(String))
dt.Columns.Add("Video", GetType(String))
dt.Columns.Add("Form", GetType(String))
dt.Columns.Add("RAM", GetType(String))
dt.Columns.Add("VRAM", GetType(String))
dt.Columns.Add("HD", GetType(String))
dt.Columns.Add("Wireless", GetType(Boolean))
End Sub
Private Sub FillDataTable()
'ReadAllLines returns an array of the lines in a text file
'inventory.txt is stored in the bin\Debug folder of your project
'This is the current directory so it does not require a full path.
Dim lines = File.ReadAllLines("inventory.txt")
'Now it is easy to split each line into fields by using the comma
For Each line As String In lines
'Split returns an array of strings with the value of each field
Dim items = line.Split(","c)
'Each item in the array can be added as a field to the DataTable row
dt.Rows.Add(items(0), items(1), items(2), items(3), items(4), items(5), items(6), CBool(items(7)))
'Notice that the last element is changed from a string to a boolean. This is
'the Wireless field which is bound to the check box. The string "True" or "False" is
'changed to a Boolean so it can be used as the .Checked property (see bindings)
Next
End Sub
Private Sub AddDataBindings()
'Create a new instance of the BindingSource class
bs = New BindingSource()
'Set the DataSource to the DataTable we just filled
bs.DataSource = dt
'Now you can set the bindings of each control
'The .Add method takes (Name of Property to Bind, the BindingSource to use, The Field name
'from the DataTable.
txtForm.DataBindings.Add("Text", bs, "Form")
txtHd.DataBindings.Add("Text", bs, "HD")
txtManufacturer.DataBindings.Add("Text", bs, "Manufacturer")
txtProcessor.DataBindings.Add("Text", bs, "Processor")
txtRam.DataBindings.Add("Text", bs, "RAM")
txtVideo.DataBindings.Add("Text", bs, "Video")
txtVram.DataBindings.Add("Text", bs, "VRAM")
'Notice on the CheckBox we are using the Checked property.
chkWireless.DataBindings.Add("Checked", bs, "Wireless")
End Sub
#End Region
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
'Add a blank row to the DataTable
'A Boolean is like a number, a String can be Nothing but a Boolean must
'have a value so we pass in False.
dt.Rows.Add(Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, False)
'Find the position of the last row
Dim i As Integer = bs.Count - 1
'Move to the new empty row
bs.Position = i
End Sub
#Region "Navigation Code"
Private Sub btnPrevious_Click(sender As Object, e As EventArgs) Handles btnPrevious.Click
'The binding source Position determins where in the data you are
'It starts at zero
If bs.Position = 0 Then
MessageBox.Show("This is the first item.")
Return 'This exits the sub, you can use Exit Sub in vb
'but Return is common in other languages so it is good to learn
Else
'As the position of the BindingSource changes the boud TextBoxes
'change their data.
bs.Position = bs.Position - 1
End If
End Sub
Private Sub btnNext_Click(sender As Object, e As EventArgs) Handles btnNext.Click
' If you are not at the end of the list, move to the next item
' in the BindingSource.
If bs.Position + 1 < bs.Count Then
bs.MoveNext()
' Otherwise, move back to the first item.
Else
bs.MoveFirst()
End If
End Sub
#End Region
#Region "Save the Data"
Private Sub SaveDataTable()
'Resave the whole file if this was a real app you would use a database
Dim sb As New StringBuilder
'A string builder keeps the code from creating lots of new strings
'Strings are immutable (can't be changed) so every time you think you are
'changing a string, you are actually creating a new one.
'The string builder is mutable (changable)
For Each row As DataRow In dt.Rows
'The ItemsArray returns an array of objects containing all the
'values in each column of the data table.
Dim rowValues = row.ItemArray
'This is a bit of Linq magic that turns the values (objects) into strings
'Underneath it is performing a For loop on each object in the array
Dim strRowValues = From o In rowValues
Select Convert.ToString(o)
'Now that we have strings we can use the String.Join with the comma
'to get the format of the text file
sb.AppendLine(String.Join(",", strRowValues))
Next
'Finally we change the StringBuilder to a real String
'The inventory.txt is stored in the bin\Debug directory so it is current directory
'no additional path required
File.WriteAllText("inventory.txt", sb.ToString)
End Sub
Private Sub Form5_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
'Because our binding is two-way any additions or changes to the text
'in the text boxes or check box are reflected in the DataTable.
SaveDataTable()
End Sub
#End Region
End Class
Once you remove the comments, there is really very little code here. The #Region...#End Region tags make it easy to collapse code sections you are not working on and find areas quickly.

Importing a CSV into a combobox, then changing other things in VB

What I want to do is import a CSV file (called fwlist.txt), that looks like this:
modelname,power type,pic,part number,firmware, option1, option 1, etc
End result, i would like a combobox that shows the modelname, and when the model name is selected from the pulldown, it updates various labels and text boxes on the form with other information.
Here's what I have so far:
Dim filename As String = "fwlist.txt"
Dim pwrtype As String
Dim pic As String
Dim partnum As String
Dim lineread As String
Dim FirmwareName As String
Private Sub ReadFirmwaresLoad(sender As Object, e As EventArgs) Handles Me.Load
' Load the items into the NameComboBox list.
Dim ResponseDialogResult As DialogResult
Try
Dim FirmwareStreamReader As StreamReader = New StreamReader(filename)
' Read all the elements into the list.
Do Until FirmwareStreamReader.Peek = -1
lineread = FirmwareStreamReader.ReadLine()
Dim fields As String() = lineread.Split(",")
FirmwareName = fields(0) 'Take First Field
cbFW.Items.Add(FirmwareName)
'Set Text labels based on position in line.
pwrtype = fields(1)
pic = fields(2)
partnum = fields(3)
(...etc through options)
Loop
' Close the file.
FirmwareStreamReader.Close()
Catch ex As Exception
' File missing.
ResponseDialogResult = MessageBox.Show("File not Found!", "File Not Found",
MessageBoxButtons.OK, MessageBoxIcon.Question)
If ResponseDialogResult = DialogResult.OK Then
' Exit the program.
Me.Close()
End If
End Try
End Sub
Private Sub cbFW_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbFW.SelectedIndexChanged
lblPwrType.Text = pwrtype
lblPic.Text = pic
lblPartNum.Text = parnum
....etc thruogh options
End Sub
This code works, but only sort of. If i select anything from the combo box, it only gives me the information from the very last line of the CSV file - even if its the first entry in the box. I'm pretty sure it's something simple that I'm messing up.. anyone help?
First we read the lines into Firmware objects then we set this List(Of Firmware) as the DataSource of the ComboBox.
Then we handle the SelectedIndexChanged event of the ComboBox which will get the currently selected firmware and loads its data to the TextBox controls.
This is a tested, working example below:
Public Class Firmware
Public Property ModelName As String
Public Property PowerType As String
Public Property Pic As String
Public Property PartNumber As String
Public Property Firmware As String
Public Property Option1 As String
End Class
Public Class MainForm
Private Sub btnLoad_Click(sender As Object, e As EventArgs) Handles btnLoad.Click
Dim lines As String() = Nothing
Try
' Read the file in one step
lines = File.ReadAllLines("fwlist.txt")
Catch ex As Exception
Dim dialogResult As DialogResult = MessageBox.Show(Me, "File not found! Would you like to exit program?", "Error reading file", MessageBoxButtons.YesNo, MessageBoxIcon.Error, MessageBoxDefaultButton.Button2)
If dialogResult = DialogResult.Yes Then
Me.Close()
End If
Exit Sub
End Try
Dim firmwares As List(Of Firmware) = New List(Of Firmware)
For Each line As String In lines
Dim rawData As String() = line.Split({","}, StringSplitOptions.None)
' Create Firmware object from each line
Dim firmware As Firmware = New Firmware() With
{
.ModelName = rawData(0),
.PowerType = rawData(1),
.Pic = rawData(2),
.PartNumber = rawData(3),
.Firmware = rawData(4),
.Option1 = rawData(5)
}
' We store the read firmwares into a list
firmwares.Add(firmware)
Next
' Set the list as the data source of the combobox
' DisplayMember indicates which property will be shown in the combobox
With cboModelNames
.DataSource = firmwares
.DisplayMember = "ModelName"
End With
End Sub
Private Sub cboModelNames_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cboModelNames.SelectedIndexChanged
RefreshForm()
End Sub
Private Sub RefreshForm()
' Get the selected item as Firmware object
Dim currentFirmware As Firmware = DirectCast(cboModelNames.SelectedItem, Firmware)
' Refresh all the textboxes with the information
With currentFirmware
txtPowerType.Text = .PowerType
txtPic.Text = .Pic
txtPartNumber.Text = .PartNumber
txtFirmware.Text = .Firmware
txtOption1.Text = .Option1
End With
End Sub
End Class
Every time you set the value of a variable like pwrtype, its old value is thrown away and there is no way to get it back. And even if you did save multiple values for each variable, you would need a way to figure out which value goes with the currently selected item in the combo box. To resolve these two issues you need:
a way to group values from the same line together
a way to save all values read from the file, not just the most recent ones
Let's start with the first issue, grouping values together. In the example code below, I created a Structure type called FirmwareInfo to serve that purpose. Each FirmwareInfo has its own pwrtype, pic, etc.
The other piece of the puzzle that you are missing is a way to save more than one Firmware. The easiest way to do this is to add each FirmwareInfo to the combo box's item list, instead of adding just the display string. The combo box will convert each item to a string in the UI; the ToString() method tells it how you want this conversion to be done.
I haven't run this example code so I can't guarantee there aren't mistakes in there, but hopefully it's enough to show the general idea.
Dim filename As String = "fwlist.txt"
Structure FirmwareInfo
Public pwrtype As String
Public pic As String
Public partnum As String
Public FirmwareName As String
Public Overrides Function ToString() As String
Return FirmwareName
End Function
End Structure
Private Sub ReadFirmwaresLoad(sender As Object, e As EventArgs) Handles Me.Load
' Load the items into the NameComboBox list.
Dim ResponseDialogResult As DialogResult
Try
Dim FirmwareStreamReader As StreamReader = New StreamReader(filename)
' Read all the elements into the list.
Do Until FirmwareStreamReader.Peek = -1
Dim lineread = FirmwareStreamReader.ReadLine()
Dim fields As String() = lineread.Split(",")
Dim info As New FirmwareInfo With {
.FirmwareName = fields(0),
.pwrtype = fields(1),
.pic = fields(2),
.partnum = fields(3)
}
cbFW.Items.Add(info)
Loop
' Close the file.
FirmwareStreamReader.Close()
Catch ex As Exception
' File missing.
ResponseDialogResult = MessageBox.Show("File not Found!", "File Not Found",
MessageBoxButtons.OK, MessageBoxIcon.Question)
If ResponseDialogResult = DialogResult.OK Then
' Exit the program.
Me.Close()
End If
End Try
End Sub
Private Sub cbFW_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbFW.SelectedIndexChanged
Dim currentInfo = DirectCast(cbFW.SelectedItem, FirmwareInfo)
lblPwrType.Text = currentInfo.pwrtype
lblPic.Text = currentInfo.pic
lblPartNum.Text = currentInfo.parnum
' ....etc through options
End Sub