关于动态创建panel及label的问题

Question

因为什么看不到label，所以确定panel是否被正确的创建
代码如下
Panel panelN = new Panel();
            panelN.Location = new System.Drawing.Point(161, 0);
            panelN.Name = "panelN";
            panelN.Size = new System.Drawing.Size(511, 390);
            panelN.TabIndex = 1;
            this.Controls.Add(panelN);
            Label l1 = new System.Windows.Forms.Label();
            l1.Location = new System.Drawing.Point(200, 0);
            l1.Name = "l1";
            l1.Size = new System.Drawing.Size(511, 390);
            l1.TabIndex = 1;
            l1.Width = this.Width - 50;
            l1.Height = this.Height - 50;
            l1.Visible = true;
            l1.Text = "111111111111111111111111111000000000000000000000011111111111111111111111111111111111";
            this.Controls.Add(l1);
            panel1.Visible = false;
            treeView1.Visible = false;

Answer 1

Panel panelN = new Panel(); 
            panelN.Location = new System.Drawing.Point(161, 0); 
            panelN.Name = "panelN"; 
            panelN.Size = new System.Drawing.Size(511, 390); 
            panelN.TabIndex = 0;  //不要和标签的相同            this.Controls.Add(panelN); 
            Label l1 = new System.Windows.Forms.Label(); 
            l1.Location = new System.Drawing.Point(200, 0); 
            l1.Name = "l1"; 
            l1.Size = new System.Drawing.Size(511, 390); 
            l1.TabIndex = 1; 
            l1.Width = this.Width - 50; 
            l1.Height = this.Height - 50; 
            l1.Visible = true; 
            l1.Text = "111111111111111111111111111000000000000000000000011111111111111111111111111111111111"; 
            this.Controls.Add(l1); 
            panel1.Visible = false; 
            treeView1.Visible = false;

Answer 2

修改完了，但还是看不到label，因为不知道tabindex是否和现有控件的冲突，所以加大到100
Panel panelN = new Panel();
            panelN.Location = new System.Drawing.Point(161, 0);
            panelN.Name = "panelN";
            panelN.Size = new System.Drawing.Size(511, 390);
            panelN.TabIndex = 100;
            this.Controls.Add(panelN);
            Label l1 = new System.Windows.Forms.Label();
            l1.Location = new System.Drawing.Point(200, 0);
            l1.Name = "l1";
            l1.Size = new System.Drawing.Size(511, 390);
            l1.TabIndex = 101;
            l1.Width = this.Width - 50;
            l1.Height = this.Height - 50;
            l1.Visible = true;
            l1.Text = "111111111111111111111111111000000000000000000000011111111111111111111111111111111111";
            this.Controls.Add(l1);
            panel1.Visible = false;
            treeView1.Visible = false;