Question

I have a login form and a button which check if the user name and the password are true.
but the problem is the code I tried .. I must click on the connect button twice.

but the code should work when I click on the button just once ! Right ?

I think the problem is: the showDialog won’t be disappeared if only I click in some button that it’s DialogResult set in some value, so in the first click the connexionButton.DialogResult gets the DialogResult.OK value and in the second click the button executes the code.

*you can notice that the event simpleButton1_Click is the event for the connexionButton Button*

this is the event I used :

  this.connexionButton.Click += new System.EventHandler(this.simpleButton1_Click);

this is the code I tried :

private void simpleButton1_Click(object sender, EventArgs e)
{
     Boolean allowCnx = false;

     foreach (var row in myClass.ds.Tables["Users"].AsEnumerable())
     {
         if (row[1].ToString().ToLower() == idBox.Text.ToLower() && row[2].ToString().ToLower() == mdpBox.Text.ToLower())
         {
            allowCnx = true;
         }
     }

     if (allowCnx)
     {
         connexionButton.DialogResult = DialogResult.OK;
     }
     else
       XtraMessageBox.Show("Invalide Information", "Erreur", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

and this is the code I used to call this login form :

using (login loginForm = new login())
{
     var result = loginForm.ShowDialog();
     if (result == DialogResult.OK)
        this.Show();
     else
        this.Close();
}

Answer 1

// Points to a different method than the one you posted
// (simpleButton1_Click_1 instead of simpleButton1_Click)
this.simpleButton1.Click += new System.EventHandler(this.simpleButton1_Click_1);

// This isn't simpleButton1_Click_1
private void simpleButton1_Click(object sender, EventArgs e)

Not sure if that is your issue, but it looks like your event handler is a different method than the one you posted. Do you have another method called simpleButton1_Click_1 somewhere in your code and you’ve just gotten slightly confused?

EDIT: In response to your changes/additions

You seem to have some confusion over ShowDialog and DialogResult.

// When you launch the login form, I do not know what you intended to do with your
// calls to Show() and Close() but so long as you don't instend for them to do
// anything to the loginForm, that's fine.
using (login loginForm = new login())
{
    if (loginForm.ShowDialog() == DialogResult.OK)
        // Do stuff if logged in
    else
        // Do stuff if failed
} 

private void simpleButton1_Click(object sender, EventArgs e)
{
    Boolean allowCnx = false;

    foreach (var row in myClass.ds.Tables["Users"].AsEnumerable())
        if (row[1].ToString().ToLower() == idBox.Text.ToLower() && row[2].ToString().ToLower() == mdpBox.Text.ToLower())
        {
            allowCnx = true;
        }

    if (allowCnx)
    {
        this.DialogResult = DialogResult.OK; // Don't set the DialogResult of a button.  Set it for the form.
    }
    else
    {
        this.DialogResult = DialogResult.Abort; // Because we didn't succeed
        XtraMessageBox.Show("Invalide Information",
            "Erreur",
            MessageBoxButtons.OK,
            MessageBoxIcon.Error);
    }
}