编写一程序，用于计算长方体表面积的程序。通过文本框输入长宽高，通过标签框显示表面积。

Question

使用VB语言，编写一程序，用于计算长方体表面积的程序。通过文本框输入长宽高，通过标签框显示表面积。界面如下图所示。

Answer 1

参考以下代码:

    Private Sub CalculateBtn_Click(sender As Object, e As EventArgs) Handles CalculateBtn.Click
        Dim length As Double
        Dim width As Double
        Dim height As Double
        Try
            length = Convert.ToDouble(txtLength.Text.Trim)
            width = Convert.ToDouble(txtWidth.Text.Trim)
            height = Convert.ToDouble(txtHeight.Text.Trim)
        Catch ex As Exception
            MessageBox.Show("请输入正确的长宽高")
        End Try

        lblSurfaceArea.Text = "长方体的表面积是:" & (length * width + length * height + width * height) * 2
    End Sub

    Private Sub ClearBtn_Click(sender As Object, e As EventArgs) Handles ClearBtn.Click
        txtLength.Text = ""
        txtWidth.Text = ""
        txtHeight.Text = ""
        lblSurfaceArea.Text = "长方体的表面积是:"
    End Sub

    Private Sub QuitBtn_Click(sender As Object, e As EventArgs) Handles QuitBtn.Click
        Application.Exit()
    End Sub

效果: