Passing with Accessors in C#

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 not passing anything, you are creating a new Form

Form1 f1 = new Form1(); 
staffmem = f1.Staffmem; 

If the data is to be shared - a really poor way is to make the string static

private static string staffmem;

Answer 2

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)

Answer 3

You're creating a whole new Form1 - wherein, you wish to use the existing instance.

What you need to do, is define Staffmem on your MainScreen object, and set it after you create it.

MainScreen ms = new MainScreen();
ms.Staffmem = btn.Text;

Then, in your MainScreen_Load: Set the value.

Answer 4

You are working with 2 different objects, first you create a Form1 object and click the button will set the property value on that single object, however in your mainscreen you create a new instance of Form1.

You could pass the form object as a reference to MainScreen itself.

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

And then in the MainScreen class update the constructor to.

public MainScreen(Form1 form)
{
    this.form1 = form;
}

And keep the reference in a field, like so.

private Form1 form1;

After this you can do this again,

private void MainScreen_Load(object sender, EventArgs e)
{  
    staffmem = form1.Staffmem;
}