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vb.net登陆 vb登录窗口

vb.net 登录问题

你每次取出的是表中的首条记录,当然只能用首条记录登陆了!

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Dim name, password As String

name = TextBox1.Text

Dim com As New OleDb.OleDbCommand("select * from denglu where name='" name "'", conn)

Dim dr As OleDb.OleDbDataReader

conn.Open()

dr = com.ExecuteReader

dr.Read()

password = dr.GetString(1)

If TextBox3.Text = password Then

mesbox("成功!")

Else

msgbox("失败")

End If

dr.Close()

conn.Close()

这种情况下,效率极不好!你能理解什么意思就行了!否则将你的程序改完了!

VB.net 如何实现记住密码 自动登录

代码如下:

/// summary

/// 连接到窗体:通过密码保护信息找回密码!

/// /summary

/// param name="sender"/param

/// param name="e"/param

private void lbl_mibao_Click(object sender, EventArgs e)

{

Getbackpwd getbackpwd = new Getbackpwd();

getbackpwd.Show();

}

/// summary

/// 当该窗体加载时从xml文件中读取用户信息并加载到combox的Items中

/// /summary

/// param name="sender"/param

/// param name="e"/param

private void Addresslist_Load(object sender, EventArgs e)

{

XmlTextReader reader = new XmlTextReader(@"E:\面向对象--C#练习\通讯录\address list\address list\user.xml");

while (reader.Read())

{

//if (reader.LocalName.Equals("Name") || reader.LocalName.Equals("Number"))

if (reader.LocalName.Equals("username"))

{

this.cmbUserName.Items.Add(reader.ReadString());

}

//if (reader.LocalName.Equals("Number"))

//{

// this.label2.Text += reader.ReadString() + "\n";\

//}

}

reader.Close();

}

/// summary

/// 保存用户名到user.xml

/// /summary

//在listcontol上更改SelectedValue时执行从数据库读取密码的事件

private void cmbUserName_SelectedValueChanged(object sender, EventArgs e)

{

string username = cmbUserName.Text.Trim();

string sql = string.Format("select pwd from Admin where Username='{0}'", username);

try

{

SqlCommand command = new SqlCommand(sql, DBHelper.connection);

DBHelper.connection.Open();

SqlDataReader dataReader = command.ExecuteReader();

while (dataReader.Read())

{

txtpwd.Text = (string)dataReader["pwd"];

checkBoxpwd.Checked = true;

}

}

catch

{

MessageBox.Show("数据库操作出错!");

}

finally

{

DBHelper.connection.Close();

}

}

/// summary

/// 记住密码操作

/// /summary

/// param name="sender"/param

/// param name="e"/param

private void checkBoxpwd_Enter(object sender, EventArgs e)

{

bool check = true;

check = checkinput(cmbUserName.Text.Trim());

if ((string)cmbUserName.Text.Trim() == "")

{

MessageBox.Show("请输入用户名", "输入提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

cmbUserName.Focus();

}

else

{

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

{

MessageBox.Show("请输入密码", "输入提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

txtpwd.Focus();

}

else

{

bool isValidUser = false; // 标识是否为合法用户

string message = ""; // 如果登录失败,显示的消息提示

// 如果验证通过,就显示相应的用户窗体,并将当前窗体设为不可见

if (ValidateInput())

{

// 调用用户验证方法

isValidUser = ValidateUser(cmbUserName.Text, txtpwd.Text, ref message);

// 如果是合法用户,显示相应的窗体

if (isValidUser)

{

if (check == true)

{

XmlDocument doc = new XmlDocument();

doc.Load(@"E:\面向对象--C#练习\通讯录\address list\address list\user.xml");//(@"E:\面向对象--C#练习\通讯录\address list\address list\user.xml");

XmlElement node = doc.CreateElement("user");

XmlNode xnode = (XmlNode)doc.CreateElement("username");

xnode.InnerText = cmbUserName.Text.Trim();

node.AppendChild(xnode);

doc.DocumentElement.InsertAfter(node, doc.DocumentElement.LastChild);

doc.Save(@"E:\面向对象--C#练习\通讯录\address list\address list\user.xml");

//doc.Load (@"E:\面向对象--C#练习\通讯录\address list\address list\user.xml");

}

}

// 如果登录失败,显示相应的消息

else

{

MessageBox.Show(message, "记住密码失败!", MessageBoxButtons.OK, MessageBoxIcon.Information);

}

}

}

}

}

/// summary

/// 验证当前combox中内容是否已经存在于xml文件中

/// /summary

/// param name="text"/param

/// returns/returns

private bool checkinput(string text)

{

int count;

bool c = true;

for (count = 0; count cmbUserName.Items.Count;count ++ )

{

if (text ==(string )cmbUserName .Items [count])

{

c=false;

}

}

return c;

}

xml文件内容如下:?xml version="1.0" encoding="utf-8"?

person

user

一个vb.net的用户登陆页面代码

Private Sub Button _Click(ByVal sender As System Object ByVal e As System EventArgs) Handles Button Click

If TextBox Text = Or TextBox Text = Then

Label Text = 请确认您的输入!

Return

End If

Dim sql As String = select * from pwd where stu_id=@stu_id and pwd=@pwd

Dim m As SqlCommand = New SqlCommand(sql conn)

m Parameters Add(New SqlParameter( @stu_id SqlDbType Int ))

m Parameters( @stu_id ) Value = TextBox Text

m Parameters Add(New SqlParameter( @pwd SqlDbType Char ))

m Parameters( @pwd ) Value = TextBox Text

Dim dr As SqlDataReader

conn Open()

dr = m ExecuteReader

If dr Read Then

Session( stu_id ) = TextBox Text

dr Close()

m Cancel()

Dim sql_ As String = update stu_base set point=point+ where stu_id=@stu_id

m = New SqlCommand(sql_ conn)

m Parameters Add(New SqlParameter( @stu_id SqlDbType Int ))

m Parameters( @stu_id ) Value = Session( stu_id )

m ExecuteNonQuery()

m Cancel()

Response Redirect( detail aspx?stu_id= Session( stu_id ) )

Else

Label Text = 您还没有注册或账号密码错误

End If

End Sub

Private Sub Button _Click(ByVal sender As System Object ByVal e As System EventArgs) Handles Button Click

TextBox Text =

TextBox Text =

lishixinzhi/Article/program/net/201311/13960

vb.net 用户登录

哈哈简单哪

第一步:登陆网页代码

第二步:登陆以后判断是否登陆成功

有两种方法:1.获取网页代码,判断网页字符有无”登陆成功”字样

源代码:

2.就是判断网页是否跳转到了某一页

源代码:

两种方法结合起来用,可以判断网页是否无法连接

vb.net用户登陆! 及判断用户存在! 我是新手啊!真的不知道错在哪里了!

Dim conn As SqlConnection

Dim cn As New SqlConnection("Data Source=(local);Initial Catalog=用户登录;" "Integrated Security=true") '链接数据库

你这里初始化了的CONNECTION其实是CN,不是CONN,

所以

Dim login As New SqlCommand(sqlstr, conn)

这里应该是

Dim login As New SqlCommand(sqlstr, cn)


标题名称:vb.net登陆 vb登录窗口
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