Classes using other classes/methods

Question

I made a program that essentially contained 150 actions, all in the first form. It has become a nightmare to manage and a friend recommended splitting groups of actions into separate classes.
Ideally going from: Do {1,2,3,4,5} to Do {A,B} where A is {1,2,3} and B is {4,5} .

To practice, I decided to try to work 2 classes:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
    public void button_Click(object sender, RoutedEventArgs e)
    {
        if (checkBox1.IsChecked == true)
        {
            checkTrue();
        }
        else
        {
            checkFalse();
        }
    }

    public void checkTrue()
    {
        textBox.Text = "checkbox was checked";
    }

    public void checkFalse()
    {
        textBox.Text = "unchecked :(";
    }
}

How would I go about changing this to a set it as a new class to be called upon? When creating a new class "checkBool", I wrote the following in a new .cs:

class checkBool
{
    public void checkTrue()
    {
        textBox.Text = "checkbox was checked";
    }

    public void checkFalse()
    {
        textBox.Text = "unchecked :(";
    }
}

However, the textbox is no longer recognized. How can I make this new class understand the reference?

Answer 1

The textbox is not recognized by the checkbool instance because it doesn't know about it.

One quick way to "let it know about it" is passing the textbox as a parameter to the checkTrue() and checkFalse() operations, like this:

class checkBool
{
    public void checkTrue(TextBox textBox)
    {
        textBox.Text = "checkbox was checked";
    }
    public void checkFalse(TextBox textbox)
    {
        textBox.Text = "unchecked :(";
    }
}

So the button click handler would be:

public void button_Click(object sender, RoutedEventArgs e)
{
    checkBool cb = new checkBool();
    if (checkBox1.IsChecked == true)
    {
        cb.checkTrue(textbox);
    }
    else
    {
        cb.checkFalse(textbox);
    }
}

Keep in mind that by doing this you are introducing a dependency to your class checkBool (It depends to TextBox now).