请帮助我完成我的项目我是编码的新手。我正在使用库存系统制作销售点，我使用TabControl和TabPages作为我的UI。我的问题是我希望我的程序知道当前登录的是我的SQL数据库上的管理员还是普通用户。我没有使用IsUserAdmin或WindowsIdentity来理解他们阅读WindowsSystem管理员权限。我想要的是我的程序只读取我的sql数据库上提供的userlevel。我仍在使用“用户”选项卡，我已完成登录表单。我希望如果我按下删除更新或添加按钮，我的程序将从我的sql数据库中读取我是否是管理员，如果我只是用户级别并且无法更新添加或删除，则会弹出一条消息任何条目。
这是我的登录代码：对我来说已经很好了。不是我的原始代码归功于我复制的代码的所有者。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace SecretCafe
{
public partial class frmLogin : Form
{
static int attempt = 3;
static string role;
public frmLogin()
{
InitializeComponent();
}
private void btnLogin_Click(object sender, EventArgs e)
{
if (attempt == 0)
{
lblMsg.Text = ("ALL 3 ATTEMPTS HAVE FAILED - CONTACT ADMIN");
return;
}
SqlConnection scn = new SqlConnection();
scn.ConnectionString = @"Data Source=DESKTOP-39SPLT0;Initial Catalog=SalesandInventory;Integrated Security=True";
SqlCommand scmd = new SqlCommand("select count (*) as count from tblUsers where [User Name]=@usr and Password=@pwd", scn);
scmd.Parameters.Clear();
scmd.Parameters.AddWithValue("@usr", txtUser.Text);
scmd.Parameters.AddWithValue("@pwd", txtPass.Text);
scn.Open();
if (scmd.ExecuteScalar().ToString() == "1")
{
MessageBox.Show("You are granted with access.");
this.Hide();
frmMain frmmain = new frmMain();
frmmain.Closed += (s, args) => this.Close();
frmmain.Show();
}
else
{
MessageBox.Show("Invalid Username or Password.");
lblMsg.Text = ("You have only " + Convert.ToString(attempt) + " attempt left to try.");
--attempt;
txtUser.Clear();
txtPass.Clear();
}
}
private void button2_Click(object sender, EventArgs e)
{
this.Close();
}
}
}
这是我的主窗口代码，它有tabControls和tabPages。工作正常，但我希望如果我按删除更新或添加按钮我的程序将读取，如果我是一个管理员或不从我的SQL数据库，并给出一个弹出消息，如果我只是一个用户级别，无法更新添加或删除任何条目。不是我的原始代码归功于我复制的代码的所有者。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace SecretCafe
{
public partial class frmMain : Form
{
SqlConnection scn = new SqlConnection(@"Data Source=DESKTOP-39SPLT0;Initial Catalog=SalesandInventory;Integrated Security=True");
SqlDataAdapter sda;
DataTable dt;
SqlCommand scmd;
public frmMain()
{
InitializeComponent();
this.MaximizeBox = false;
show();
}
private void btnSave_Click(object sender, EventArgs e)
{
try
{
scn.Open();
String qry = "insert into tblUsers values ('" + txtLastName.Text + "', '" + txtName.Text + "', '" + txtAddress.Text + "', '" +dateTimePicker1.Value + "', '" + txtUserLevel.Text + "', '" + txtUserName.Text + "', '" + txtPassword.Text + "')";
scmd = new SqlCommand(qry, scn);
int i = scmd.ExecuteNonQuery();
if (i >= 1)
MessageBox.Show(i + " User has been added successfully: " + txtName.Text);
else
MessageBox.Show("User not added!");
show();
scn.Close();
btnClear_Click(sender, e);
}
catch (System.Exception exp)
{
MessageBox.Show("Error is " + exp.ToString());
}
}
private void btnUpdate_Click(object sender, EventArgs e)
{
try
{
scn.Open();
String qry = "update tblUsers set [First Name]='" + txtName.Text + "', Address='" + txtAddress.Text + "', Birthday= '" + dateTimePicker1.Value + "', [User Level]= '" + txtUserLevel.Text + "', [User Name]= '" + txtUserName.Text + "', Password= '" + txtPassword.Text + "' where [Last Name]='" + txtLastName.Text + "'";
scmd = new SqlCommand(qry, scn);
int i = scmd.ExecuteNonQuery();
if (i >= 1)
MessageBox.Show(i + " User has been updated successfully: " + txtName.Text);
else
MessageBox.Show("Update Failed! - Last Name can't be updated.");
show();
scn.Close();
btnClear_Click(sender, e);
}
catch (System.Exception exp)
{
MessageBox.Show("Error is " + exp.ToString());
}
}
void show() {
sda = new SqlDataAdapter("select [Last Name], [First Name], Address, Birthday, [User Name], [User Level], Password from tblUsers", scn);
dt = new DataTable();
sda.Fill(dt);
dataGridView1.Rows.Clear();
foreach (DataRow dr in dt.Rows)
{
int n = dataGridView1.Rows.Add();
dataGridView1.Rows[n].Cells[0].Value = dr[0].ToString();
dataGridView1.Rows[n].Cells[1].Value = dr[1].ToString();
dataGridView1.Rows[n].Cells[2].Value = dr[2].ToString();
dataGridView1.Rows[n].Cells[3].Value = dr[3].ToString();
dataGridView1.Rows[n].Cells[4].Value = dr[4].ToString();
dataGridView1.Rows[n].Cells[5].Value = dr[5].ToString();
dataGridView1.Rows[n].Cells[6].Value = dr[6].ToString();
}
}
private void dataGridView1_MouseClick_1(object sender, MouseEventArgs e)
{
try
{
txtLastName.Text = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();
txtName.Text = dataGridView1.SelectedRows[0].Cells[1].Value.ToString();
txtAddress.Text = dataGridView1.SelectedRows[0].Cells[2].Value.ToString();
dateTimePicker1.Value = Convert.ToDateTime(dataGridView1.SelectedRows[0].Cells[3].Value);
//dateTimePicker1.Value = DateTime.ParseExact(dataGridView1.Rows[e.GetType].Cells[3].Value.ToString(), "yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture);
txtUserName.Text = dataGridView1.SelectedRows[0].Cells[4].Value.ToString();
txtUserLevel.Text = dataGridView1.SelectedRows[0].Cells[5].Value.ToString();
txtPassword.Text = dataGridView1.SelectedRows[0].Cells[6].Value.ToString();
}
catch (Exception exp)
{
MessageBox.Show("Error is " + exp.ToString());
}
}
private void btnDelete_Click(object sender, EventArgs e)
{
try
{
DialogResult dlteUser = MessageBox.Show("Do you intend to remove this User?", "Warning",
MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
if (dlteUser == DialogResult.Yes)
{
scn.Open();
String qry = "delete from tblUsers where [Last Name]='" + txtLastName.Text + "'";
scmd = new SqlCommand(qry, scn);
int i = scmd.ExecuteNonQuery();
if (i >= 1)
MessageBox.Show(i + " User has been removed successfully: " + txtName.Text);
else
MessageBox.Show("User deletion failed!");
show();
scn.Close();
btnClear_Click(sender, e);
}
else if (dlteUser == DialogResult.No)
{
}
}
catch (System.Exception exp)
{
MessageBox.Show("Error is " + exp.ToString());
}
}
private void btnClear_Click(object sender, EventArgs e)
{
txtName.Clear();
txtLastName.Clear();
txtAddress.Clear();
dateTimePicker1.Value = DateTime.Now;
txtUserLevel.Clear();
txtUserName.Clear();
txtPassword.Clear();
}
}
}
您可以按照本文中的建议查询当前用户的SQL Server角色。
How to query current user's roles
SELECT u.name, r.name
FROM sys.database_role_members AS m
INNER JOIN sys.database_principals AS r
ON m.role_principal_id = r.principal_id
INNER JOIN sys.database_principals AS u
ON u.principal_id = m.member_principal_id
WHERE u.name = @user;
这将提供您在SQL Server中为用户指定的角色的名称