C# と VB.NET の質問掲示板

■No65263 (YU さん) に返信

ドロップダウンしてよければ以下のようでどうでしょう？

    Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        ComboBox1.DataSource = Enumerable.Range(1, 1000).Select(Function(i) String.Format("Item{0}", i)).ToList
    End Sub

    Private Sub ComboBox1_MouseWheel(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles ComboBox1.MouseWheel
        If Not ComboBox1.DroppedDown Then
            ComboBox1.DroppedDown = True
        End If
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        TextBox1.Focus()
    End Sub