Generic CheckBox Creator function adding anonymous event handlers with referenced property

Question

I want to create a bunch of simple checkboxes for a Windows from and have them change bools. Because it is a lot of them, I thought I could skip writing a bunch of CheckedChanged handlers and have a generic "Creator" function like this

    static CheckBox CreateCheckBox(ref bool binding, string name)
    {
        var box = new CheckBox();
        box.Checked = binding;
        box.CheckedChanged += (object sender, EventArgs e) => { binding = !binding; };
        box.Text = name;
        return box;
    }

And Then create my boxes like:

ParentForm.Controls.Add(CreateCheckBox(ref prop1, nameof(prop1));
ParentForm.Controls.Add(CreateCheckBox(ref prop2, nameof(prop2));
.....

I obviously got the "Can't use ref in a lambda expression or anonymous function". I read up on it and it makes sense. But is there a way to have this sort of simple creator function that that generically adds the handlers?

I know there would be an issue here with never removing the handler but this is for a debug mode feature that is only used by developers to debug and improve very specific.algorithm. Maybe I am just being lazy to write and add all the handlers but I also just felt cleaner.

Answer 1

You do not need to pass anything by reference, use one of the following options:

1. Pass a getter Func and a setter Action
2. Setup databinding

Example 1 - Pass a getter Func or a setter Action

Pass the getter and setter as func/action:

public CheckBox CreateCheckBox(string name, Func<bool> get, Action<bool> set)
{
    var c = new CheckBox();
    c.Name = name;
    c.Text = name;
    c.Checked = get();
    c.CheckedChanged += (obj, args) => set(!get());
    return c;
}

And use it like this, for example:

CreateCheckBox("checkBox1", () => textBox1.Enabled, (x) => textBox1.Enabled = x);
CreateCheckBox("checkBox2", () => textBox2.Enabled, (x) => textBox2.Enabled = x);

Example 2 - Setup databinding

What you are trying to implement is what you can achieve by setting up data binding:

public CheckBox CreateCheckBox(string name, object dataSource, string dataMember)
{
    var c = this.Controls[name] as CheckBox;
    c.Name = name;
    c.Text = name;
    c.DataBindings.Add("Checked", dataSource,
        dataMember, false, DataSourceUpdateMode.OnPropertyChanged);
    return c;
}

And use it like this:

CreateCheckBox("checkBox1", textBox1, "Enabled");
CreateCheckBox("checkBox2", textBox2, "Enabled");