C#基础知识及题目练习 Day13 windows窗体 MDI窗体 Directory ComboBox ComboBox OpenFileDialog 记事本应用

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("I love you");
        }

        private void button2_Click(object sender, EventArgs e)
        {
            MessageBox.Show("好吧，我投降了！");
        }

        private void button2_MouseEnter(object sender, EventArgs e)
        {
            //找到鼠标可以移动的最大范围
            int fx = this.ClientSize.Width;
            int fy = this.ClientSize.Height;
            int w = button2.Width;
            int h = button2.Height;
            int x = fx - w;
            int y = fy - h;

            Random r = new Random();
            Point p = new Point();//坐标
            p.X = r.Next(0, x);
            p.Y = r.Next(0, y);
            button2.Location = p;


        }
    }

所有知识基本上都是围绕着类，定时器也不例外，Timer类属性方法

Enable:控件是否可用
Interval：时间间隔希望定时器多久执行一次计时单位是ms 1s=1000ms

Tick事件：事件到了，让定时器做什么，在该事件中实现

获取当前时间：DateTime类

Start():启动定时器
Stop():停止定时器

让窗体居中：StarPosition 改成：CenterScreen

Timer:在指定的时间间隔内做一些事情

eg2:动态的显示当前时间：

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            textBox1.Text = DateTime.Now.ToString();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            timer1.Start();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            timer1.Stop();
        }
    }

eg3:跑马灯

关键：timer事件中，将字符串的第一个字符放到最后。

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            string str = textBox1.Text;
            string tou = str.Substring(0, 1);
            string sub = str.Substring(1, str.Length - 1)+tou;
            textBox1.Text = sub.ToString();
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            timer1.Start();
        }

        private void btnStop_Click(object sender, EventArgs e)
        {
            timer1.Stop();
        }
    }

eg4：简单记事本NoteBook

窗体1（登录）：

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textUser.Text == "admin" && textPwd.Text == "123")
            {
                this.Hide();
                MessageBox.Show("欢迎光临！");
                Form2 f2 = new Form2();
                f2.Show();

            }
            else
            {
                MessageBox.Show("输入错误！");
            }
        }
    }

窗体2（写字板）：

public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
            textBox1.WordWrap = false;
        }

        private void 自动换行ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            textBox1.WordWrap = true;
        }

        private void 保存ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            using(StreamWriter sw=new StreamWriter(@"E:\notebook.txt", false, Encoding.Default))
            {
                sw.Write(textBox1.Text);
                MessageBox.Show("保存成功！");
            }
        }

        private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }

注：1.让文本框变成密码框：设置textBox1的PasswordChar属性为 *。

2.将文本框的WordWrap属性设为True----自动换行

eg5:单选和多选

Checked:指示控件是否处于选中状态

默认情况下，单选控件只能被选中一个，用GroupBox进行分组

        private void button1_Click(object sender,