C# How can I check to see if a checkbox is checked on another form?

Question

I'm using C# and I'd like to check to see if a checkbox on the main form is checked and if so run some code, the problem is I'm in a class file (file with no form, is class file correct?). What is the easiest way to do this?

Thanks Jamie

Answer 1

The best option is to create a boolean property on the Form that exposes the Checked value of the CheckBox.

public bool OptionSelected
{
    get { return checkBox.Checked; }
    set { checkBox.Checked = value; } // the set is optional
}

Answer 2

You need a reference to the form, and the form has to expose the checkbox (or a property which consults the checkbox).

There's no difference between UI programming and non-UI programming in this respect. How would ask for the Name property of a Person instance from a different class? You'd get a reference to the instance, and ask for the relevant property.

So you definitely need a reference to the form, and then it's one of:

bool checked = form.IsAdultCheckbox.Checked;
bool checked = form.IsAdult; 

(Where the IsAdult property would return someCheckbox.Checked.)

The actual property names may be wrong here (e.g. Checked may not return a bool) but I hope you get the idea.

Answer 3

Can you define an interface with a property, have the form implement the interface and return true if the checkbox is checked, and pass an instance of this interface to your class?

For example:

interface IMyFormFlag
{
    bool IsChecked { get; }
}

public class MyForm : Form, IMyFormFlag
{
    CheckBox chkMyFlag;

    bool IsChecked { get { return chkMyFlag.Checked; } }
}

public class MyObject
{
    public void DoSomethingImportant(IMyFormFlag formFlag)
    {
        if (formFlag.IsChecked)
        {
            // do something here
        }
    }
}

Answer 4

Personally, I don't like using set or get. I did it like this:

if (checkBox.IsChecked.Equals(true))
{
//insert code here
}

Answer 5

you can use this it works fine for me

    if (Convert.ToBoolean(CheckBox1.IsChecked))
      {
         MessageBox.Show("true");
      }
    else
       {
         MessageBox.Show("false"); 
       }