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

Question

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?

Answer 1

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

Answer 2

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)