我想编辑一个可以解出复数根的一元二次方程计算器，结果老是卡在第二个else这里。
麻烦大家帮我看下究竟该怎么改，谢谢！
Private Sub CmdSolve_Click()
    Dim a As Single: a = Val(Text1.Text)
    Dim b As Single: b = Val(Text2.Text)
    Dim c As Single: c = Val(Text3.Text)
    Dim p As Single: p = b ^ 2 - 4 * a * c
    Dim x1 As Single, X2 As Single, e As Single, f As Single
    If a = 0 Then
        Text4.Text = "无解"
        Text5.Text = "无解"
    Else: If p >= 0 Then x1 = (-b + Sqr(p)) / (2 * a): X2 = (-b - Sqr(p)) / (2 * a): Text4.Text = x1: Text5.Text = X2
            Else: e = -b / (2 * a): f = (Sqr(-p)) / (2 * a): Text4.Text = Str(e) & "+" & Str(f) & "i": Text5.Text = Str(e) & "+" & Str(f) & "i"
        End If
    End If
End Sub