c# Activate panel on form1 from form2

Question

So I'm working on a ordering system, when order gets placed from form2, to show a panel with message on form1.. but It doesnt seem to work, please help

                int chkComm1 = comm1.ExecuteNonQuery();

            if(chkComm1 == 1)
            {
                //so basically if query call is successful (which it is) it should open a panel with message on my main program or form1, but It doesnt work? anyone help?
                Main_Program mp = new Main_Program();
                mp.orderALERT.Enabled = true;
                mp.orderALERT.Visible = true;
                mp.Refresh();

            }

After this code it should show panel but nothing happens, if someone can help me please do! Thanks !

Answer 1

Problem: Your code is not working, because you create new instance of form1 which is not related to main form which you already have in your application:

Main_Program mp = new Main_Program(); // here

Solution: You should use form1 which is already opened. That is easy to do with events. Create an event on form2:

public event EventHandler OrderPlaced;

And raise it when order is placed:

int chkComm1 = comm1.ExecuteNonQuery();

if(chkComm1 == 1)
{
    OrderPlaced?.Invoke(this, EventArgs.Empty);
}

On form1 subscribe to event of form2:

form2.OrderPlaced += Form2_OrderPlaced;

And in event handler activate panel:

private void Form2_OrderPlaced(object sender, EventArgs e)
{
    orderALERT.Enabled = true;
    orderALERT.Visible = true;
}

Answer 2

Pass in your instance of Main_Program to the Show() method of Form2 like this:

public partial class Main_Program : Form
{
    public Main_Program()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form2 f2 = new Form2();
        f2.Show(this); // pass in THIS instance of Main_Program as the "Owner"
    }

}

Now, over in Form2, you can cast the Owner back to Main_Program and manipulate. To access your "orderALERT" Panel, however, you must change its Modifiers property to public:

public partial class Form2 : Form
{

    public Form2()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (this.Owner != null && this.Owner is Main_Program)
        {
            Main_Program mp = (Main_Program)this.Owner;
            mp.orderALERT.Enabled = true;
            mp.orderALERT.Visible = true;
            mp.orderALERT.Refresh();
        }
    }

}