用VB6.0制作验证码，当提示验证错误后为何又提示验证正确？

这是验证码程序

Private Sub Picture1_Click()

Randomize Timer

y = ""

Picture1.Cls

For i = 1 To 4

Picture1.FontSize = Int(Rnd * 13 + 12)

j = Int(Rnd * 4) + 1

If i = j Then Picture1.FontItalic = True

k1 = Int(Rnd * 256)

k2 = Int(Rnd * 256)

k3 = Int(Rnd * 256)

Picture1.ForeColor = RGB(k1, k2, k3)

k = Int(Rnd * 3)

Select Case k

Case 0: a = 48: b = 57

Case 1: a = 65: b = 90

Case 2: a = 90: b = 122

End Select

x = Int(Rnd * (b - a + 1) + a)

y = y & Chr(x)

Picture1.Print Chr(x) & "";

Picture1.FontItalic = False

Next i

End Sub

这是验证按钮程序

Private Sub Command3_Click()

If UCase(Text3.Text) = UCase(y) Then

MsgBox "验证成功", vbInformation, "成功"

Else

MsgBox "验证码错误", vbCritical, "警告"

Text3.Text = ""

Text3.SetFocus

Call Command3_Click

End If

End Sub