Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick Dim textBoxes As New List(Of TextBox) textBoxes.Add(TextBox2) textBoxes.Add(TextBox3) textBoxes.Add(TextBox4) For Each t In textBoxes If t.Text <> "" Then TextBox1.Text = "全て記入済み" ElseIf t.Text = "" Then TextBox1.Text = "未記入有り" End If Next End Sub