Question

I am having a bit of trouble passing variable between forms. I have created a button array and want to pass the button text to the next form. But this is just returning a Null value

In the first form

private string staffmem;
    public string Staffmem
    {
        get
        {
            return staffmem;
        }
    }

    public void ClickButton(Object sender, EventArgs e)
    {          
        Button btn = (Button)sender;
        staffmem = btn.Text;
        MessageBox.Show("Welcome " + staffmem);

        MainScreen ms = new MainScreen();
        ms.Show();
    }

and then in the second form

        private void MainScreen_Load(object sender, EventArgs e)
    {  
        Form1 f1 = new Form1();
        staffmem = f1.Staffmem;

Any help would be much appreciated. Thanks in advance

Answer 1

You are creating new forms in both ends of the communication: when the button is clicked and when you want to retrieve the text — this results in accessing the Staffmem field on a newly created object, which field has not been set to anything, hence the returned null value.

In order to be able to retrieve the text, you need to have the same Form1 object to MainScreen when it is created:

MainScreen ms = new MainScreen(form1);

where form1 is the actual Form1 object, and store it in MainScreen as a member variable

// in MainScreen class
private Form1 f1;

Then access Staffmem on that object on the stored member variable:

// in MainScreen_Load()
staffmem = f1.Staffmem;

Note: depending on your need, you might not want to create a new MainScreen from every time the button is clicked either. In that case (if you already have a created MainScreen that you want to communicate with), you need to pass the MainScreen object to the Form1 object as well, when the Form1 object is created (following the above outlined techniqe)