如何使计算控件所控制的TEXT控件允许为空呢？

Private Sub Command1_Click()
当这个TEXT控件不需要计算时？请看代码：

Dim x, y, c, ha, hb As Single
Dim x2, y2, c2, ha2, hb2 As Single
Dim x3, y3, c3, ha3, hb3 As Single
Dim x4, y4, c4, ha4, hb4 As Single

ha = Val(Text1.Text)
hb = Val(Text2.Text)
c = Val(Text3.Text)
y = 1000 * (ha - hb)
x = 500 * Sqr(c * c - (ha - hb) * (ha - hb))
Text10.Text = Val(x)
Text11.Text = Val(y)

ha2 = Val(Text2.Text)
hb2 = Val(Text4.Text)
c2 = Val(Text5.Text)
y2 = 1000 * (ha2 - hb2)
x2 = 500 * Sqr(c2 * c2 - (ha2 - hb2) * (ha2 - hb2))
Text12.Text = Val(x2)
Text13.Text = Val(y2)

。。。
。。。

End Sub

当我只计算到：x2, y2, c2, ha2, hb2 所在的TEXT时，而下面的为空，

执行时，出现提示框：


无效的过程调用或参数


如何修改呢？

If Text6.Text <> "" Then

...
...
Text14.Text = Val(x3)
Text15.Text = Val(y3)
Else
Text14.Text = ""
Text15.Text = ""

我就这么解决的！

可能代码臃肿了些！
End If