Calling function from different form-CodePudding

I am currently working on a Rythm Game for for my course project, and I am having trouble implementing BGM on/off button.

Here is my simplified code:

Form1

public partial class Form1 : Form
    {
    public SplashScreen()
        {
            InitializeComponent();
            
            string path= System.Reflection.Assembly.GetEntryAssembly().Location;
            axWindowsMediaPlayer1.settings.volume = 0;
            axWindowsMediaPlayer1.Ctlcontrols.stop();
            axWindowsMediaPlayer1.URL = path.Remove(path.Length - 44)   "\\assets\\main.wav";
        }
        
        
        void BGMoff()
        {
            axWindowsMediaPlayer1.settings.mute = true;
        }
        void BGMon()
        {
            axWindowsMediaPlayer1.settings.mute = false;
        }
        
        
        private void Form1_Load(object sender, EventArgs e)
        {
            Form2 main = new Form2();
            main.BGM_off  = BGMoff;
            main.BGM_on  = BGMon;
        }
    }

Form2

public partial class Form2 : Form
        
    {
        public delegate void ClickButton();
        public event ClickButton BGM_off;
        public event ClickButton BGM_on;
        
        bool BGM = true
        
        public void button4_Click_1(object sender, EventArgs e)
        {
            if (BGM)
            {
                button4.BackgroundImage = Properties.Resources.BGMoff;
                BGM = false;
                BGM_off?.Invoke();
            }
            else
            {
                button4.BackgroundImage = Properties.Resources.BGMon;
                BGM = true;
                BGM_on?.Invoke();


            }
        }
    }

This was made based on comment from this thread by Darin. I believe I followed the steps correctly to get access to axWindowsMediaPlayer, but I was wrong.

CodePudding user response：

You can easily call the function of another form by creating and saving the second form in a variable and call the function from it.

CodePudding user response：

Looks like your issue is that in this line in Form1_Load:

Form2 main = new Form2();

main is created as a local variable.
After you allocate it and register to the events, it goes out of scope.

You can make it a member variable of Form1 instead:

public partial class Form1 : Form
{
    // ...
    Form2 main;
    // ...
}

This way the lifetime of main will be related to the lifetime of your Form1.
You code in Form1_Load should be:

main = new Form2();       // NOTE: this is the member this.main
main.BGM_off  = BGMoff;
main.BGM_on  = BGMon;

CodePudding user response：

After frustraiting hours of experementation with code i realized my mistake.

It was in a part of code i didnt even include as it was somewhat unrelated to event handling itself.

main.Show(this); is the culprid. It's code used to open new form, aka switch between menues. I was creating new object form2 of Form2 and going there instead of the one where we signed up for events, therefore events were returning null. and failing to execute functions.