Question

I am working on windows application using c#.

I have a from say X, in which i have a label say label1, This x from code class X.cs is

inheriting the class say FormManager.cs (Custom Methods to control the common functionality on

all forms on Form load or Form close). I am running a thread on the FormManager.cs to perform

some repeated task and from where i want to change the change the label text of label1 from

this FormManager.cs class. How can i do this.

Answer 1

1. Your base class don’t know about your label, so you can’t update your label from the base class.
2. If you are running a background thread to update UI, then you’ll have to Invoke so the UI update will be performed in the UI thread. Here’s an implementation example:

FormManager form:

public partial class FormManager : Form
{
    public FormManager()
    {
        InitializeComponent();
    }

    public Action BackgroundActionCompleted { get; set; }

    public void OnBackgroundActionCompleted()
    {
        if (this.BackgroundActionCompleted != null)
        {
            // Invoke so the action will be launched on the UI thread
            this.Invoke(this.BackgroundActionCompleted);
        }
    }
}

X form:

public partial class X : FormManager
{
    public X()
    {
        InitializeComponent();
    }

    private void X_Load(object sender, EventArgs e)
    {
        this.BackgroundActionCompleted = delegate() { this.label2.Text = "New Text"; };
    }
}