Can't recreate an object in .NET Winforms 4.8.1 C#

Question

I'm trying to make a settings program for a project I'm working on, and I need a way to unload objects (specifically pictureboxes and labels). I probably will need the objects later, but I don't want them constantly loaded in memory, because I want to make my program as lightweight as I can.

I've tried nulling my objects, and it does null them, but now I can't RE-load them.

Here is the code:

    public void LoadPage(string URL)
    {
        if (URL != currentPage)
        {
            if (this.SystemRootIcon != null)
            {
                this.SystemRootIcon.Dispose();
            }
            if (URL == "Root")
            {
                if (this.SystemRootIcon == null)
                {
                    this.SystemRootIcon = new System.Windows.Forms.PictureBox();
   // Below does not run
                    debug.Text = "RUNNING!";
                    ((System.ComponentModel.ISupportInitialize)(this.SystemRootIcon)).BeginInit();
                    this.splitContainer1.Panel2.Controls.Add(this.SystemRootIcon);
                    this.SystemRootIcon.BackgroundImage = global::New_Control_Panel.Properties.Resources.imageres_195;
                    this.SystemRootIcon.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch;
                    this.SystemRootIcon.Location = new System.Drawing.Point(12, 42);
                    this.SystemRootIcon.Name = "SystemRootIcon";
                    this.SystemRootIcon.Size = new System.Drawing.Size(48, 48);
                    this.SystemRootIcon.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
                    this.SystemRootIcon.TabIndex = 18;
                    this.SystemRootIcon.TabStop = false;
                    this.SystemRootIcon.Visible = true;
                    ((System.ComponentModel.ISupportInitialize)(this.SystemRootIcon)).EndInit();
                }
                currentPage = URL;
            }
        }
    }

Answer 1

this.SystemRootIcon.Dispose(); does not set the value of SystemRootIcon to null, thus the later condition if (this.SystemRootIcon == null) will never be true. You need to set it to null explicitly after dispose.

Instead of testing for null, you could also test for IsDisposed instead. That might be a bit safer to do, since it does not involve null tests and therefore bears less risks of running into NullReferenceExceptions.

So the first condition should be something like:

            if (this.SystemRootIcon != null)
            {
                this.SystemRootIcon.Dispose();
                this.SystemRootIcon = null;
            }