private void Loginbtn_Click(object sender, EventArgs e)
 {
     if (usernameTxt.Text == null || usernameTxt.Text == "Enter Username")
     {
         usErrorLable.Visible = true;
     }
     else
     {
         usErrorLable.Visible = false;
     }
     if (passwordTxt.Text == null || passwordTxt.Text == "Password")
     {
         PAssErrorLable.Visible = true;
     }
     else
     {
         PAssErrorLable.Visible = false;
     }
     if (usErrorLable.Visible || PAssErrorLable.Visible)
     {
         MainClass.ShowMSG("Fields with * are required ", "Required", "Error");
     }
     else
     {
         if (Main.staffLogin(usernameTxt.Text, passwordTxt.Text))
         {
             HomeScreen HS = new HomeScreen();
             MainClass.showwindows(HS, this, MDI.ActiveForm);
         }
         else
         {
             MainClass.ShowMSG("Invalid Login Details", "Error", "Error");
         }
     }
 }