form1.cs

Visual C#2005程序设计教程

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WinApp3_8大小写转换
{
    public partial class Form1 : Form
    {
        string init;
        public Form1()
        {
            InitializeComponent();
        }

        private void txtInfo_KeyPress(object sender, KeyPressEventArgs e)
        {
        }

        private void btnUpper_Click(object sender, EventArgs e)
        {
            txtInfo.Text = txtInfo.Text.ToUpper();
        }

        private void btnLower_Click(object sender, EventArgs e)
        {
            txtInfo.Text = txtInfo.Text.ToLower();
        }

        private void btnInit_Click(object sender, EventArgs e)
        {
            txtInfo.Text = init;
        }

        private void txtInfo_KeyUp(object sender, KeyEventArgs e)
        {
            init = txtInfo.Text;
        }
    }
}