i want to customize the candidate window of japanese input, but it seems not
working well and ImmNotifyIME always return false, my source list as below:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Me.TextBox1.Focus()
Me.txthandle = Me.TextBox1.Handle
Dim str = "�れ�����ゃ"
Dim enc As Encoding = Encoding.GetEncoding(932)
Dim bt() As Byte = Encoding.GetEncoding(932).GetBytes("ã�„ã‚Œã�Ÿã�¦ã� ®ã�Šã�¡ã‚ƒ")

Me.himc = ImmGetContext(Me.txthandle)
ImmSetOpenStatus(hIMC, 1)
Dim j = ImmSetCompositionString(himc, SCS_SETSTR, str,
enc.GetByteCount(str), "", 0)
'Dim j = ImmSetCompositionString(himc, SCS_SETSTR, bt(0), bt.Length,
Nothing, 0)

j = ImmNotifyIME(himc, NI_OPENCANDIDATE, 0, 0)
MsgBox(j)

End Sub