Get list of open windows form instance that are excuted from different assembly

Question

I have a 'loader app' that loads a menu and when user clicks the menu image button a list view opens based on the text

(if text = employee)  
(Go to class A) 
(Go to class B) 
    ...
    ...
    (Show List View Window) 

if he clicks again on the same button it opens again, I would like to prevent this. i.e but this for a WPF application

Answer 1

If you want a list of the open forms, that is Application.OpenForms. You could iterate over this, using GetType() and checking the .Assembly to find those from a different assembly. Beyond that, I'm not entire clear on the question...

        Assembly currentAssembly = Assembly.GetExecutingAssembly();
        List<Form> formsFromOtherAssemblies = new List<Form>();
        foreach (Form form in Application.OpenForms) {
            if (form.GetType().Assembly != currentAssembly) {
                formsFromOtherAssemblies.Add(form);
            }
        }

If you just want to track forms you have opened yourself, then cache that instance. Or if you use "owned forms", you can just check by name:

    private void button1_Click(object sender, EventArgs e) {
        foreach (Form form in OwnedForms) {
            if (form.Name == "Whatever") {
                form.Activate();
                return;
            }
        }
        Form child = new Form();
        child.Name = "Whatever";
        child.Owner = this;
        child.Show(this);
    }

Answer 2

    NewProduct newproduct;
    private void button1_Click(object sender, EventArgs e)
    {

        if(!isOpened())
        {
            newproduct = new NewProduct();
            newproduct.Show();
        }

    }
    private bool isOpened()
    {
        foreach (Form f in Application.OpenForms)
        {
            if (f == newproduct)
            {
                return true;
            }
        }
        return false;
    }