Accessing Form's Control from another class C#

Question

I\'m a newbie in c# and visual studio, but not programming in general. I searched for answer to my question for 3 days and I found plenty of them, but for some weird reason

Answer 1

The problem is you are setting the value to a new instance of the form. Try something like this:

public partial class Form3 : Form {
    public string setCodes
    {
        get { return test1.Text; }
        set { test1.Text = value; }
    }

    private A a;

    public Form3()
    {
        InitializeComponent();
        a = new A(this);
    } 

    private void button1_Click(object sender, EventArgs e)
    {            
        a.b();            
    }


    private void Form3_Load(object sender, EventArgs e)
    {

    }
}

public class A
{       
    private Form3 v;

    public a(Form3 v)
    {
        this.v = v;
    }

    public void b()
    {
        v.setCodes = "abc123";
    }
}    

Answer 2

You're creating a brand new Form3() instance.
This does not affect the existing form.

You need to pass the form as a parameter to the method.

Answer 3

Sending form instance to other other class

Form1 objForm1=new Form1();
obj.Validate(objForm1);

Easy way to access controls in another class by modifying Controls Private to Public in the Form(Designer.cs)

Answer 4

Try this:

public partial class Form3 : Form
{
    /* Code from question unchanged until `button1_Click` */

    private void button1_Click(object sender, EventArgs e)
    {
        a.b(this);
    }
}

public class a
{       
    public static void b(Form3 form3)
    {
        form3.setCodes = "abc123";
    }
}

This passes the current instance of the form to the other class so that it can update the setCodes property. Previously you were creating a new form instance rather than updating the current form.