C# Access active Form from another active Form-CodePudding

Hey I am kinda stuck here and could need a little help or reference.

I have one main form (Form1) and two sub forms (Form2 & Form3). On Form1 is a Panel (Panel1) with two Buttons (Button1 & Button2). If I click Button1 I want to display Form2 inside the Panel of Form1. If I click Button2 I want to display Form3 inside the Panel of Form1.

I got that working already with the following code (Button1 Click):

        Form2.TopLevel = false;
        Panel1.Controls.Add(Form2);
        Form2.FormBorderStyle = FormBorderStyle.None;
        Form2.Dock = DockStyle.Fill;
        Form2.Show();

now to my actual problem. In Form1 I have booleans, integers and strings that I want to reach (read and write) from Form2 and Form3.

Since Form1 and either Form 2 or Form 3 are active I can't just use "Form1 form1 = new Form1;" since initializing a new form doesn't use the already created instance. It's a new form so it has the default values from start and not the changed ones from the active Form1 which I want.

So now I want to have a field in Form2 and Form3 to hold the active instance of Form1 so that I can change and read the values of the actual active Form.

How would I do that?

CodePudding user response：

Pack all data you want to pass from form 1 in a class. ( define a class for this ).

You can define constructors for Form 2 and 3 and pass the instance of type you defined from form 1 to 2 and 3. That is one way of doing this.

Another way is to define properties for Form 2 and 3 and assign values before you call .Show() method. This is not a great idea if your form 2 and 3 can be used some where else and you may accidentally not assign the values to the properties.

CodePudding user response：

Did you create instances of Form2 and Form3 in Form1? If Yes, just add an argument to the constructor of both sub forms.

UPDATED

// In Form1
public partial class Form1 : Form
{
    private readonly Form2 _form2;

    public Form1()
    {
        _form2 = new Form2(this);
        InitializeComponent();
    }
}

// In Form2
public partial class Form2 : Form
{
    private readonly Form1 _form1;

    public Form2(Form1 form1)
    {
        _form1 = form1;
        InitializeComponent();
    }

}