C#.net登录界面及密码

启动、登陆界面

public partial class Form1 : Form

{

int lianNum = 1;//错误次数的计算

public Form1()

{

InitializeComponent();

}

//利用用户名、密码、权限ID作为条件，查询是否有符合条件的用户，执行后得到myreader的记录存在的话，则登陆成功，否则登陆失败

private void button1_Click(object sender, EventArgs e)

{ //连接数据库

string str_sqlconnection = "Data Source=.;Initial Catalog=caiwuData;Integrated Security=True";

SqlConnection conn = new SqlConnection(str_sqlconnection);

if (textBox1.Text.Trim() != "" && textBox2.Text.Trim() != "")

{

SqlCommand cmd = new SqlCommand();

cmd = new SqlCommand("select * from yonghuTab join quanxiangTab on yonghuTab.权限ID=quanxiangTab.权限ID where 用户名="+"'"+textBox1.Text+"'"+" and 密码

="+"'"+textBox2.Text+"'and 权限名='"+comboBox1.Text+"'",conn);

try

{

conn.Open();

SqlDataReader myreader = cmd.ExecuteReader();

if (myreader.Read())

{

MessageBox.Show("登陆成功，恭喜！", "提示！");

Form2 f2 = new Form2();

this.Hide();

f2.Show();

}

else

{

conn.Close();

if (lianNum++ > 4)//判断输入次数超过3次就弹出提示框

{

MessageBox.Show("连接错误次数超过3次", "提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);

this.Close();

}

Else

{

MessageBox.Show("用户名，密码，或权限错误", "提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);

}

}

}

catch (Exception ee)

{

MessageBox.Show(ee.Message.ToString(),"提示！");

}

}

else

{

MessageBox.Show("还有未填项目！！", "提示！", MessageBoxButtons.OK, MessageBoxIcon.Warning);

if (textBox2.Text.Trim() == "")

{

textBox2.Focus();

}

else

{

textBox1.Focus();

}

}

}

private void textBox2_TextChanged(object sender, EventArgs e)

{

}

//（2）并在输入密码时系统提示“请输入6-14位的密码”；当鼠标离开密码框时，提示消失。

private void textBox2_MouseMove(object sender, MouseEventArgs e)

{

label5.Visible = true;

}

private void textBox2_MouseLeave(object sender, EventArgs e)

{

label5.Visible = false;

}

//单击button2 关闭应用程序

private void button2_Click(object sender, EventArgs e)

{

Application.Exit();

}

private void textBox1_KeyDown(object sender, KeyEventArgs e)

{

if (e.KeyCode == Keys.Enter || e.KeyCode == Keys.Left || e.KeyCode == Keys.Right || e.KeyCode == Keys.Down)

{

textBox2.Focus();

}

}

//按回车，向下、向上、向左或向右的箭头键发生事件

private void textBox2_KeyDown(object sender, KeyEventArgs e)

{

if (e.KeyCode == Keys.Enter || e.KeyCode == Keys.Down || e.KeyCode == Keys.Right) {

comboBox1.Focus();

}

else if (e.KeyCode == Keys.Up || e.KeyCode == Keys.Left)

{

textBox1.Focus();

}

}

private void comboBox1_KeyDown(object sender, KeyEventArgs e)

{

if (e.KeyCode == Keys.Up || e.KeyCode == Keys.Left)

{

textBox2.Focus();

}

else

if (e.KeyCode == Keys.Right || e.KeyCode == Keys.Enter)

{

button1.Focus();

}

}

private void button1_KeyDown(object sender, KeyEventArgs e)

{

if (e.KeyCode == Keys.Enter)

{

button2.Focus();

}

}

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)

{

}

private void Form1_Load(object sender, EventArgs e)

{

// TODO: 这行代码将数据加载到表“caiwuDataDataSet.quanxiangTab”中。您可以根据需要移动或移除它。

this.quanxiangTabTableAdapter.Fill(this.caiwuDataDataSet.quanxiangTab);

}

}

}