Lesson 6: Mastering ListBox and ComboBox in VB2022

Private Sub BtnAdd_Click(sender As Object, e As EventArgs) Handles BtnAdd.Click
    ' Add a single item
    MyListBox.Items.Add("Vivo")
    
    ' Add multiple items using an array
    Dim colors() As String = {"Red", "Green", "Blue"}
    MyListBox.Items.AddRange(colors)
    
    ' Add items using InputBox
    Dim newItem As String = InputBox("Enter item to add:")
    If Not String.IsNullOrEmpty(newItem) Then
        MyListBox.Items.Add(newItem)
    End If
End Sub

Private Sub BtnRemove_Click(sender As Object, e As EventArgs) Handles BtnRemove.Click
    ' Remove by item text
    If MyListBox.Items.Contains("Vivo") Then
        MyListBox.Items.Remove("Vivo")
    End If
    
    ' Remove by index
    If MyListBox.Items.Count > 0 Then
        MyListBox.Items.RemoveAt(0)  ' Remove first item
    End If
    
    ' Clear all items
    If MessageBox.Show("Clear all items?", "Confirmation", 
                      MessageBoxButtons.YesNo) = DialogResult.Yes Then
        MyListBox.Items.Clear()
    End If
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    ' Set SelectionMode to MultiExtended
    MyListBox.SelectionMode = SelectionMode.MultiExtended
End Sub

Private Sub BtnShowSelected_Click(sender As Object, e As EventArgs) Handles BtnShowSelected.Click
    Dim selectedItems As New System.Text.StringBuilder()
    
    ' Loop through all selected items
    For Each item As Object In MyListBox.SelectedItems
        selectedItems.AppendLine(item.ToString())
    Next
    
    If selectedItems.Length > 0 Then
        MessageBox.Show("Selected items:" & Environment.NewLine & selectedItems.ToString(), 
                        "Selected Items")
    Else
        MessageBox.Show("No items selected", "Information")
    End If
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    ' Add items at form load
    myCombo.Items.Add("VB2022")
    myCombo.Items.Add("VB2019")
    myCombo.Items.Add("VB6")
    
    ' Set default selection
    myCombo.SelectedIndex = 0
End Sub

Private Sub BtnAdd_Click(sender As Object, e As EventArgs) Handles BtnAdd.Click
    Dim newItem = InputBox("Enter new item:")
    If Not String.IsNullOrEmpty(newItem) Then
        ' Add if not already present
        If Not myCombo.Items.Contains(newItem) Then
            myCombo.Items.Add(newItem)
        End If
    End If
End Sub

Private Sub BtnRemove_Click(sender As Object, e As EventArgs) Handles BtnRemove.Click
    Dim itemToRemove = InputBox("Enter item to delete")
    
    If itemToRemove IsNot Nothing AndAlso myCombo.Items.Contains(itemToRemove) Then
        myCombo.Items.Remove(itemToRemove)
    Else
        MessageBox.Show("Item not found", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
    End If
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    ' Configure autocomplete
    myCombo.AutoCompleteMode = AutoCompleteMode.SuggestAppend
    myCombo.AutoCompleteSource = AutoCompleteSource.ListItems
    
    ' Add country names
    Dim countries() As String = {"United States", "Canada", "Mexico", 
                          "Brazil", "Argentina", "Chile", "United Kingdom", 
                          "France", "Germany", "Italy", "Spain"}
    myCombo.Items.AddRange(countries)
    
    ' Set default selection
    myCombo.SelectedIndex = 0
End Sub