a part of CdoMail.cls

cdoMail2.bas

Public Sub SetAddress( _
    ByVal addrTo As Variant, _
    '省略
    )
    
    xMsg.To = GetAddrList(addrTo)
    '省略
End Sub

Private Function GetAddrList(ByVal addlst As Variant) As String
    If IsArray(addlst) Then GetAddrList = Join(addlst, "; ") Else GetAddrList = CStr(addlst)
End Function