新手求助,关于修改密码页面,请大家帮忙,谢谢

[xuxinunuon]

我初学c#，想做一个修改用户密码的窗体，连接的sql2000，我的思路是先连接数据库读取到该用户相应的密码，然后和textBoxOld对比，如果二者相等的话，继续验证新密码textBoxNew.Text和确认密码textBoxNewQueren.Text是否相等，若相等的话，就把新密码更新到原来的密码处。

不知道这个思路怎么样，写了一部分，然后就不太会写了，请大家帮帮我，谢谢大家。


if (textBoxNewQueren.Text == textBoxNew.Text)
{

SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=db_showHouse;Integrated Security=True");
SqlCommand cmd = new SqlCommand("select (*) from tb_User", conn);//不知道这么写对不对....
conn.Open();
string aa = cmd.EndExecuteNonQuery();
conn.Close();
if (aa == textBoxOld.Text)
{
//更新数据库，不会写.......
}


}
else
{
MessageBox.Show("您的密码输入有误，请重新输入！");
textBoxNew.Text = "";
textBoxNewQueren.Text = "";
}

[生活真美好]

先找本书看吧，如Visual C# 2005 管理系统开发经典案例

[zzyhuian06142]

if (textBoxNewQueren.Text == textBoxNew.Text)
{

SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=db_showHouse;Integrated Security=True");
SqlCommand cmd = new SqlCommand("select 密码 from tb_User where 用户名='"+用户名+"'", conn conn.Open();
string aa = （string）cmd.Excultscale();
if (aa == textBoxOld.Text)
{
cme.CommaneText ="Update tb_User set 密码= '"+textBoxNew.Text+"' where 用户名='"+用户名+"'";
cmd.ExcultNoQuery();
conn.Close();
}
else
{
MessageBox.Show("密码不匹配!");
}


}
else
{
MessageBox.Show("新密码和确认密码不一致，请重新输入！");
textBoxNew.Text = "";
textBoxNewQueren.Text = "";
}

[生活真美好]

//记录用户登录次数
private int MyTryCount = 0;
private void 登录系统Button_Click(object sender, EventArgs e)
{
//从app.config文件中读取数据库连接字符串信息
String MySQLConnectionString = global::MyHotel.Properties.Settings.Default.MyHotelConnectionString;
string MySQL = "Select COUNT(*) From 操作用户 Where 用户名称=@用户名称 AND 用户密码=@用户密码";
SqlConnection MyConnection = new SqlConnection(MySQLConnectionString);
MyConnection.Open();
SqlCommand MyCommand = new SqlCommand(MySQL, MyConnection);
MyCommand.Parameters.Clear();
SqlParameter MySqlNameParameter = new SqlParameter();
MySqlNameParameter.ParameterName = "@用户名称";
MySqlNameParameter.Value = this.用户名称TextBox.Text;
MyCommand.Parameters.Add(MySqlNameParameter);
SqlParameter MySqlPWParameter = new SqlParameter();
MySqlPWParameter.ParameterName = "@用户密码";
MySqlPWParameter.Value = this.用户密码TextBox.Text;
MyCommand.Parameters.Add(MySqlPWParameter);
int MyCount = (int)MyCommand.ExecuteScalar();
if (MyCount == 1)
{
this.Close();
}
else
{
this.MyTryCount += 1;
if (this.MyTryCount != 3)
{
int MyDoCount = 3 - this.MyTryCount;
MessageBox.Show("用户密码或用户名称有错，还有" + MyDoCount + "次机会！", "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
this.用户密码TextBox.Text = "";
this.用户名称TextBox.Text = "";
}
else
{
退出系统Button_Click(null, null);
}
}
if (MyConnection.State == ConnectionState.Open)
{
MyConnection.Close();
}
}

[icebear2]

if (comboBox2.Text == "")
{
MessageBox.Show("用户名不能为空！");
return;
}
if (textBox3.Text == textBox4.Text)
{
if (获取密码(comboBox2.Text) == textBox2.Text)
{
OleDbConnection con = new OleDbConnection(通用数据.连接字符串);
string ss = @"UPDATE user1 SET password1 = '" + textBox4.Text + "' WHERE (num = " + 用户编号 + ")";
OleDbCommand com = new OleDbCommand(ss, con);
con.Open();
com.ExecuteNonQuery();
con.Close();
MessageBox.Show("修改成功！");
}
else
{
MessageBox.Show("你输入的密码有误！请重试");
}
}
else
{
MessageBox.Show("你两次输入的新密码不一致！请重试");
}

[icebear2]

if (comboBox2.Text == "")
{
MessageBox.Show("用户名不能为空！");
return;
}
if (textBox3.Text == textBox4.Text)
{
if (获取密码(comboBox2.Text) == textBox2.Text)
{
OleDbConnection con = new OleDbConnection(通用数据.连接字符串);
string ss = @"UPDATE user1 SET password1 = '" + textBox4.Text + "' WHERE (num = " + 用户编号 + ")";
OleDbCommand com = new OleDbCommand(ss, con);
con.Open();
com.ExecuteNonQuery();
con.Close();
MessageBox.Show("修改成功！");
}
else
{
MessageBox.Show("你输入的密码有误！请重试");
}
}
else
{
MessageBox.Show("你两次输入的新密码不一致！请重试");
}

[icebear2]

private string 获取密码(string usename)
{
string 密码 = "";
try
{
OleDbConnection con = new OleDbConnection(通用数据.连接字符串);
string ss = @"SELECT TOP 1 password1, num FROM user1 WHERE (name1 = '" + usename + "')";
OleDbCommand com = new OleDbCommand(ss, con);
OleDbDataAdapter da = new OleDbDataAdapter(com);
DataSet ds = new DataSet();
con.Open();
ds.Clear();
da.Fill(ds);
con.Close();
密码 = ds.Tables[0].Rows[0][0].ToString();
用户编号 = ds.Tables[0].Rows[0][1].ToString();
}
catch { }
return 密码;
}

[hao1hao2hao3]

还是先看一些教程吧！这些都是与数据库交互最基础的东西。