Question

I want to be able to add some amount of progressbars into the form (the number of progressbars can vary from user to user).

I have written this code to add 1 progressbar:

        ProgressBar progressbar = new System.Windows.Forms.ProgressBar();
        progressbar.Name = "progressBar1";
        progressbar.Size = new Size(280, 30);
        progressbar.TabIndex = 9;
        progressbar.Show();
        flowLayoutPanel.Container.Add(progressbar);

When I run this code, I get an Exception: "Object reference not set to an instance of an object.".
What bothers me is that both the progressbar and flowLayoutPanel aren’t null when I look at them using IDE. What have I done wrong?

Answer 1

I’m guessing flowLayoutPanel.Container is null. I think you want

flowLayoutPanel.Controls.Add(progressbar);