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I have 3 classes: Form1, LoginForm and program.

Program holds my main method that then runs loginform, if a condition inside login form is met then form1 is run.

What I want it to do is hide loginform just before I show form1.

How do I do this since I can't use loginform.hide();

Here's code:

namespace RepSalesNetAnalysis { public partial class LoginForm : Form { public bool letsGO = false; public LoginForm() { InitializeComponent(); } private static DataTable LookupUser(string Username) { const string connStr = "Server=10asaf;" + "Database=dfafa;" + "uid=bufaf;" + "pwd=dridfsdf;" + "Connect Timdf0;"; //"Data Source=apex2006sql;Initial Catalog=Leather;Integrated Security=True;"; const string query = "Select password From dbo.UserTable (NOLOCK) Where UserName = @UserName"; DataTable result = new DataTable(); using (SqlConnection conn = new SqlConnection(connStr)) { conn.Open(); using (SqlCommand cmd = new SqlCommand(query, conn)) { cmd.Parameters.Add("@UserName", SqlDbType.VarChar).Value = Username; using (SqlDataReader dr = cmd.ExecuteReader()) { result.Load(dr); } } } return result; } private void buttonLogin_Click(object sender, EventArgs e) { if (string.IsNullOrEmpty(textUser.Text)) { //Focus box before showing a message textUser.Focus(); MessageBox.Show("Enter your username", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Information); //Focus again afterwards, sometimes people double click message boxes and select another control accidentally textUser.Focus(); return; } else if (string.IsNullOrEmpty(textPass.Text)) { textPass.Focus(); MessageBox.Show("Enter your password", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Information); textPass.Focus(); return; } //OK they enter a user and pass, lets see if they can authenticate using (DataTable dt = LookupUser(textUser.Text)) { if (dt.Rows.Count == 0) { textUser.Focus(); MessageBox.Show("Invalid username.", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error); textUser.Focus(); return; } else { string dbPassword = Convert.ToString(dt.Rows[0]["Password"]); string appPassword = Convert.ToString(textPass.Text); //we store the password as encrypted in the DB //MessageBox.Show Console.WriteLine(string.Compare(dbPassword, appPassword)); if (string.Compare(dbPassword, appPassword) == 0) { DialogResult = DialogResult.OK; this.Close(); } else { //You may want to use the same error message so they can't tell which field they got wrong textPass.Focus(); MessageBox.Show("Invalid Password", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Information); textPass.Focus(); return; } } } } }

}

Am i missing something? heres my main class;

namespace RepSalesNetAnalysis { static class Program { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); LoginForm fLogin = new LoginForm(); if (fLogin.ShowDialog() == DialogResult.OK) { Application.Run(new Form1()); } else { Application.Exit(); } } } }
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  • did you try This.close() function.. Commented Dec 13, 2011 at 13:56
  • this.Hide();​​​​​​​​​​​​​​​​​​​​​​​​​ Commented Dec 13, 2011 at 13:58
  • 2
    I suggest moving all of the authentication code into a separate class. Get it out of a form. Commented Dec 13, 2011 at 13:59

3 Answers 3

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4

Steven this is all wrong ground up.

there are other ways to do what you need properly having the Main method of your Program class creating a login form and only if login is successful you instantiate and show the main application form.

check this question/answer for details and examples: How can I close a login form and show the main form without my application closing?

you in fact need this approach:

static void Main() { LoginForm fLogin = new LoginForm(); if (fLogin.ShowDialog() == DialogResult.OK) { Application.Run(new MainForm()); } else { Application.Exit(); } }
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4 Comments

ok so i changed the main class program to your example, when i hit the button on login form nothing happens, because in the if statement im not actually doing anything. what needs to go in there?
if login is successful close form by setting DialogResult to DialogResult.Ok, in the login form.
not sure i understand that. in my loginform class, in the if statment where login is successfull, i need to say dialogresult.ok?
ok ive updated my post to show the changes. works fine. is this a hotfix? or is this the way you would do it? i.e better OOP implementation. reason i ask is because im very weak skilled when it comes to OOP
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You can set DialogResult to OK or Cancel in your LoginForm. This will close your LoginForm and returns the DialogResult back to your Main method. Then check the result in your Main method like this.

[STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); LoginForm form = new LoginForm(); if (form.ShowDialog() == DialogResult.OK) Application.Run(new Form1()); }

hope this helps

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static class Program { private static bool canLogin; /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); using (LoginForm loginForm = new LoginForm()){ // show as dialog // perform logic to check if successful canLogin = SomeStaticClass.VerifyCredentials(loginForm.Credentials); // grab any properties you may want here } //then run the application if(canLogin){ Application.Run(new Form1()); } } } }
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2 Comments

are you sure you can call a constructor with no '()' and there is no logic to check if login was really done and successful
the OP can provide the rest of the logic. Thanks for pointing out the missing () ...

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