我的Visual Basic GUI无法反映代码计算

Question

当我将笔的数量输入相应的文本框并按计算按钮时，程序不会显示在适当的输出文本框中计算总价。 Visual Studio不显示语法或构建错误。

https://github.com/Alamofire/Alamofire/issues/646

Public Class Form1
    Private Sub btnCalculate_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnCalculate.Click
        Dim dbltxtPensTotalPrice As Double = CDbl(txtPensQuantity.Text) * 25.55
    End Sub

    Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
        Me.Close()
    End Sub
End Class