一个VB问题！消除命按纽不起作用？？？

提问者：钱哆哆f  |  浏览 次  |  提问时间：2017-02-05  |  回答数量：6

Private Sub Command1_Click() Dim a As Single, b As Single a = Val(Text1.Text) b = Val(Text2.Text) h = Val(Text3.Text) Text4.Text = (a + b) * h / 2End SubPrivate Sub Text2_GotFocus() Text2.SelStart = 0 Text2.SelLength = Len(Text2.Text)End SubPrivate Sub Text1_GotFocus() Text1.SelStart = 0 Text1.SelLength = Len(Text1.Text)End SubPrivate Sub Text3_GotFocus() Text3.SelStart = 0 Text3.SelLength = Len(Text3.Text)End SubPrivate Sub Text1_Change() Text4.Text = \"\"End SubPrivate Sub Text2_Change() Text