vb.net小demo（计算器、文件处理等/C#也可看）

Demo1：使用窗体控件实现一个简易版计算器

Public Class Form1
    Private Sub Button_1_Click(sender As Object, e As EventArgs) Handles Button_1.Click
        CalSubBox.Text += Button_1.Text
    End Sub

    Private Sub Button_2_Click(sender As Object, e As EventArgs) Handles Button_2.Click
        CalSubBox.Text += Button_2.Text
    End Sub

    Private Sub Button_3_Click(sender As Object, e As EventArgs) Handles Button_3.Click
        CalSubBox.Text += Button_3.Text
    End Sub

    Private Sub Button_4_Click(sender As Object, e As EventArgs) Handles Button_4.Click
        CalSubBox.Text += Button_4.Text
    End Sub
    Private Sub Button_5_Click(sender As Object, e As EventArgs) Handles Button_5.Click
        CalSubBox.Text += Button_5.Text
    End Sub
    Private Sub Button_6_Click(sender As Object, e As EventArgs) Handles Button_6.Click
        CalSubBox.Text += Button_6.Text
    End Sub
    Private Sub Button_7_Click(sender As Object, e As EventArgs) Handles Button_7.Click
        CalSubBox.Text += Button_7.Text
    End Sub
    Private Sub Button_8_Click(sender As Object, e As EventArgs) Handles Button_8.Click
        CalSubBox.Text += Button_8.Text
    End Sub
    Private Sub Button_9_Click(sender As Object, e As EventArgs) Handles Button_9.Click
        CalSubBox.Text += Button_9.Text
    End Sub
    Private Sub Button_0_Click(sender As Object, e As EventArgs) Handles Button_0.Click
        CalSubBox.Text += Button_0.Text
    End Sub


    Private Sub Button_Add_Click(sender As Object, e As EventArgs) Handles Button_Add.Click
        CalSubBox.Text += Button_Add.Text

    End Sub

    Private Sub Button_Sub_Click(sender As Object, e As EventArgs) Handles Button_Sub.Click
        CalSubBox.Text += Button_Sub.Text
    End Sub

    Private Sub Button_Mul_Click(sender As Object, e As EventArgs) Handles Button_Mul.Click
        CalSubBox.Text += Button_Mul.Text
    End Sub

    Private Sub Button_Exc_Click(sender As Object, e As EventArgs) Handles Button_Exc.Click
        CalSubBox.Text += Button_Exc.Text
    End Sub
    Private Sub Button14_Click(sender As Object, e As EventArgs