mscorlib.dll VB.net中发生类型'System.FormatException'的未处理的异常

Question

我正在为我的学校项目编写一些计算应用程序，我正在使用的代码是

Private Sub C1A_Leave(sender As Object, e As EventArgs) Handles C1A.Leave
        If C1A.Text = "" Then
        Else
            C2A.Text = Double.Parse(C1A.Text) * Double.Parse(C1ER.Text)
            If SellMove.Checked = True Then
                C1NC.Text = Double.Parse(C1OC.Text) - Double.Parse(C1A.Text)
                C2NC.Text = Double.Parse(C2OC.Text) + Double.Parse(C2A.Text)
            ElseIf BuyMove.Checked = True Then
                C1NC.Text = Double.Parse(C1OC.Text) + Double.Parse(C1A.Text)
                C2NC.Text = Double.Parse(C2OC.Text) - Double.Parse(C2A.Text)
            End If
            C2A.Text = CDec(C2A.Text).ToString("N")
            C1A.Text = CDec(C1A.Text).ToString("N")
            C1NC.Text = CDec(C1NC.Text).ToString("N")
            C2NC.Text = CDec(C2NC.Text).ToString("N")
        End If
    End Sub

但是我收到了mscorlib.dll VB.net中发生的'System.FormatException'类型的未处理异常的错误

问题是，当C1OC和C2OC文本= 0时，它可以工作，但是如果它不为0，则向我显示错误。

请帮助