完成Userform以启用命令按钮

Question

我有以下代码来完成用户表单，然后在ListBox中选择的相应工作表上提交信息。我有命令按钮，只有在从ListBox中选择了工作表时才提交信息。我需要为每个TextBox做同样的帮助，以便用户在提交之前必须完整填写表单。谢谢你的帮助。

Private Sub UserForm_Initialize()
    Dim ws As Worksheet
        CommandButton1.Enabled = False
        For Each ws In ThisWorkbook.Worksheets
            ListBox1.AddItem (ws.Name)
        Next ws
End Sub

Private Sub ListBox1_Change()
    CommandButton1.Enabled = ListBox1.ListIndex <> -1
End Sub

Private Sub CommandButton1_Click()
    whichSheet = ListBox1.Value
    Dim n As Integer

    Do
        n = n + 1
        ListBox1.AddItem Sheets(n).Name
    Loop Until n = Worksheets.Count

    Worksheets(whichSheet).Activate
    Dim lastrow
    lastrow = ActiveSheet.Cells(Rows.Count, 1).End(xlUp).Row

    lastrow = lastrow + 1
    Cells(lastrow, 1) = TextBox1
    answer = MsgBox("Are you sure you want to add the record?", vbYesNo + vbQuestion, "Add Record")
    If answer = vbYes Then
        Cells(lastrow, 1) = TextBox1.Text
        Cells(lastrow, 2) = TextBox2.Text
        Cells(lastrow, 3) = TextBox4.Text
        Cells(lastrow, 4) = TextBox5.Text
        Cells(lastrow, 5) = TextBox6.Text
    Else
        Cells(lastrow, 1) = ""
        Exit Sub
    End If

End Sub