using System;

 using System.Drawing;

 using System.Windows.Forms;

 namespace 案例演示

 {

 public partial class frmlogo : Form

 {

 public frmlogo()

 {

 InitializeComponent();

 }

 int usi,pwi;

 private void frmlogo_Load(object sender, EventArgs e)

 {

 }

 private void textBox1_MouseDown(object sender, MouseEventArgs e)

 {

 usi++;

 if (usi==)

 {

 textBox1.Text = "";

 }

 if (textBox2.Text=="")

 {

 pwi = ;

 textBox2.Text = "密码";

 }

 }

 private void textBox2_MouseDown(object sender, MouseEventArgs e)

 {

 pwi++;

 if (textBox1.Text=="")

 {

 textBox1.Text = "用户名";

 usi = ;

 }

 if (pwi==)

 {

 textBox2.Text = "";

 }

 }

 private void textBox1_KeyDown(object sender, KeyEventArgs e)

 {

 textBox1.ForeColor = Color.Black;

 }

 private void textBox2_KeyDown(object sender, KeyEventArgs e)

 {

 textBox2.ForeColor = Color.Black;

 }

 private void button1_Click(object sender, EventArgs e)

 {

 }

 }

 }

 --