How to expand & reduce panel?

Question

I have two panels in tabcontrol.
I want to make panel B reduce when I expand panel A.
and panel A reduce when I expand panel B.
so I mean how to adjust two panels?!
Thank you!

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Edit------------
I would like to move like this.

Answer 1

Instead of two panels, insert a SplitContainer control and change its Orientation property to "Horizontal".

Answer 2

@LooBi , Welcome to Microsoft Q&A, you could adjuest two panel's size and location to expand or reduce the two panels.

Here is a code example you could refer to.

   Panel panel1 = new Panel();  
        Panel panel2 = new Panel();  
        private void Form1_Load(object sender, EventArgs e)  
        {  
            
            panel1.BackColor = Color.Blue;  
            panel1.Size=new Size(tabPage1.Width,tabPage1.Height/2);  
            panel1.Click += Panel1_Click;  
            TextBox textBox1 = new TextBox();  
            textBox1.Text = "Hello";  
            panel1.Controls.Add(textBox1);  
  
            panel2.BackColor = Color.Yellow;  
            panel2.Size = new Size(tabPage1.Width, tabPage1.Height / 2);  
            panel2.Location = new Point(panel1.Left, panel1.Bottom);  
            panel2.Click += Panel2_Click;  
            CheckBox checkBox1 = new CheckBox();  
            checkBox1.Text = "Do you agree";  
            checkBox1.Checked = false;  
            panel2.Controls.Add(checkBox1);  
            tabPage1.Controls.Add(panel1);  
  
            tabPage1.Controls.Add(panel2);  
        }  
  
        private void Panel2_Click(object sender, EventArgs e)  
        {  
            panel1.Size = new Size(tabPage1.Width, (tabPage1.Height / 3));  
            panel2.Size = new Size(tabPage1.Width, (tabPage1.Height / 3)*2);  
            panel2.Location = new Point(panel1.Left, panel1.Bottom);  
        }  
  
        private void Panel1_Click(object sender, EventArgs e)  
        {  
            panel1.Size = new Size(tabPage1.Width, (tabPage1.Height / 3) * 2);  
            panel2.Size = new Size(tabPage1.Width, (tabPage1.Height / 3));  
            panel2.Location = new Point(panel1.Left, panel1.Bottom);  
  
        }  

Result:

As the above picture shown, when I click panel1, panel1 will expand and panel2 will reduce, so on the panel2.

Best Regards,
Jack

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