表单打开后启用按钮C＃

Question

currently my window is like this with the edit and delete button disabled . In order to enable the buttons, user have to login with the administrator type . Right now, I already login with the administrator type from the member type. The disabled buttons supposed to be enabled after I logged in with the administrator type, but it is not.

Is there any way to enable the button, after the form opened with the buttons disabled ?

Here is the images:

As you can see on the below image, there is a admin login button with edit and delete buttons disabled. (Main System Form):

Administrator Login (Privelege Form)

Here is the code that I am using:

public class SystemManager
{
    public static void AdminLogin(string _value1, string _value2, Form _windowsForm, TextBox _windowsTextBox)
            {
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    string query = "SELECT * FROM [Member] WHERE [Username] = @Username";

                    connection.Open();

                    using (OleDbCommand command = new OleDbCommand(query, connection))
                    {
                        command.Parameters.Add("@Username", OleDbType.VarChar);
                        command.Parameters["@Username"].Value = _value1;

                        using (OleDbDataReader reader = command.ExecuteReader())
                        {
                            if (reader.Read())
                            {
                                string password = (string)reader["Password"];
                                string userType = (string)reader["UserType"];

                                _isValidPassword = BCrypt.ValidateHash(_value2, password);

                                if (userType == "Administrator")
                                {
                                    _isAdministrator = true;
                                }

                                else if (userType != "Administrator")
                                {
                                    _isAdministrator = false;
                                }

                                if (_isValidPassword && _isAdministrator)
                                {
                                    Authenticate _authenticate = new Authenticate();

                                    _authenticate.ShowDialog();

                                    ShowMessageBox("Authenticated.", "Success", 2);

                                    UserInformation.isAdministrator = true;

                                    _windowsForm.Hide();

                                    _windowsForm.Close();
                                }

                            }

                            if (!_isValidPassword || !_isAdministrator)
                            {
                                Authenticate _authenticate = new Authenticate();

                                _authenticate.ShowDialog();

                                ShowMessageBox("Either username or password incorrect or you are not administrator. Please try again.", "Error", 1);

                                ClearTextBoxes(_windowsForm.Controls);

                                _windowsTextBox.Focus();
                            }

                            reader.Close();
                        }
                    }

                    connection.Close();
                }
            }
}

public partial class MainSystem: Form
{
void MainSystem_Load(object sender, EventArgs e)
        {
            UserPrivelege();
        }

    void UserPrivelege()
             {
                 if (UserInformation.CurrentLoggedInUserType == "Member")
                 {
                     this.button3.Enabled = false; // Edit Button
                     this.button4.Enabled = false; // Delete Button
                     this.button7.Enabled = false;
                     this.button9.Enabled = true; // Admin Login Button
                 }

                 else if (UserInformation.CurrentLoggedInUserType == "Administrator" || UserInformation.isAdministrator)
                 {
                     this.button3.Enabled = true; // Edit Button
                     this.button4.Enabled = true; // Delete Button
                     this.button7.Enabled = true;
                     this.button9.Enabled = false; // Admin Login Button
                 }

             }
}

public partial class Privelege : Form
    {
        void button1_Click(object sender, EventArgs e) // OK Button
        {
            Check();
        }

        void Check()
        {
            if (this.textBox1.Text == string.Empty || string.IsNullOrWhiteSpace(this.textBox1.Text))
            {
                SystemManager.ShowMessageBox("Username field required.", "Information", 2);
            }

            else if (this.textBox2.Text == string.Empty || string.IsNullOrWhiteSpace(this.textBox2.Text))
            {
                SystemManager.ShowMessageBox("Password field required.", "Information", 2);
            }

            else
            {
                SystemManager.AdminLogin(this.textBox1.Text, this.textBox2.Text, this, this.textBox1);
            }
        }

Thank you.

I really appreciate your answer.

Answer 1

There are several architectural issues here which when resolved will also make this function the way you want. First of all it is not ideal to call a function from a form which will act upon that form. It is a much better practice to return what is needed from that function and have the code to digest that result in the form which it affects. Let's try a simple example of what the login button could do:

    private void btnLogin_Click(object sender, EventArgs e)
    {
        var login = new LoginForm();

        login.ShowDialog();

        var result = login.DialogResult == System.Windows.Forms.DialogResult.Yes;

        if (result)
        {
            button2.Enabled = true;
            button3.Enabled = true;
        }
    }

Obviously the only way this would work is if your login for was setting its DialogResult property, which is a simple way to pass a result from a modal dialog. We still have the issue of converting a login result to that value. This can be addressed in the login button of the dialog, and the login method it calls.

    private void btnDialogLogin_Click(object sender, EventArgs e)
    {
        // Form validation here...

        var result = SystemManager.AdminLogin(NameButton.Text, PassButton.Text);

        DialogResult = DialogResult.No;

        if (result)
        {
            DialogResult = DialogResult.Yes;
        }

        this.Close();
    }

Now we have to change the AdminLogin method to a boolean:

public class SystemManager
{
    public static bool AdminLogin(string _value1, string _value2)
    {
        // Database and evluation...

        if(isAdmin)
        {
            return true;
        }

        return false;
    }
}

This will make it easy to pass values as they are needed, without each object knowing more details about the other than is necessary. If the admin login needs to pass more information than just if the user is an admin, than create a class which contains all the different things one might want to know about the user's login and pass that as a return instead.

Answer 2

您可以在此处执行的操作是，一旦用户在您的第一个表单上单击登录，就可以向第二个表单的构造函数发送布尔值，对admin表示true，对其他表单说false，并根据此值可以启用或禁用您的按钮。

Answer 3

The form load event, MainSystem_Load() , is only fired once (at first initialization). The UserPrivelege() function isn't called after the admin login. You will need to invoke that functionality after the admin logs in.

Answer 4

assign value to UserInformation.CurrentLoggedInUserType and on click of Admin login button open your login form as dialog and after close of this form call UserPrivelege(); fuction

Admin login onclick :-

  PrivelegeForm frm= new LoginForm();

   DialogResult result=  frm.ShowDialog();



    if (result==DialogResult.Ok)
    {
        UserPrivelege();
    }

don't forget to assign your static variable UserInformation.CurrentLoggedInUserType