APIでコンボボックスにアイテムを追加する
'フォームにコンボボックスをを１つ貼り付ける
Option Explicit
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA"
(ByVal hwnd As Long, ByVal wMsg As Long, _
ByVal wParam As Long, _
ByVal lParam As Any) As Long
Private Const CB_ADDSTRING = &H143
Private Sub Form_Load()
Dim lngCmbhwnd As Long 'コンボボックスのハンドル
Dim intLoop As Long
Dim lngRet As Long
Dim strAdd As String
'コンボボックスのハンドルを取得する
lngCmbhwnd = Me.Combo1.hwnd
For intLoop = 1 To 30000
strAdd = "あああ" & intLoop & vbNullString
lngRet = SendMessage(lngCmbhwnd, CB_ADDSTRING, 0, strAdd)
Next intLoop
End Sub