private void btnLogin_Click(object sender, EventArgs e)
 {
     StockServiceClient service = new StockServiceClient();
     if (service.AuthenticateUser(txtUserName.Text.Trim(), txtPassword.Text))
     {
         ParentForm.CurrentUser = txtUserName.Text.Trim();
         this.DialogResult = DialogResult.OK;
         BackToParent();
     }
     else
     {
         lblError.Text = "Foutieve Gebruikersnaam/Paswoord";
         lblError.Visible = true;
     }
 }
        private void btnLogin_Click(object sender, EventArgs e)
        {
            StockServiceClient service = new StockServiceClient();

            if (service.AuthenticateUser(txtUserName.Text.Trim(), txtPassword.Text))
            {
                ParentForm.CurrentUser = txtUserName.Text.Trim();
                this.DialogResult      = DialogResult.OK;
                BackToParent();
            }
            else
            {
                lblError.Text    = "Foutieve Gebruikersnaam/Paswoord";
                lblError.Visible = true;
            }
        }