c# WinForms -通过编程创建表单的自定义边框只显示左边框和上边框

尝试学习编程，并一直在尝试。遇到了一个小问题，我还没能找到解决办法。我有一个以编程方式创建的按钮和一个以编程方式创建新表单的单击事件。表单有一些已创建的标签，以及自定义边框。在主表单上使用相同的自定义边框，即使在自动大小和动态创建内容更改其大小的情况下也可以工作。但是在这个编程创建的形式的边界只显示在左侧和顶部，我还没有能够找到答案或通过实验解决它。

不知道有多少代码是足够的，但我做了一个简化的程序来显示问题。它是从我的程序代码中简化出来的，我的程序代码使用了数百个以编程方式创建的按钮和几个信息数组，这些数组填充了myForm表单上使用的标签，所以有些事情可能看起来很奇怪，因为我删除了数组和按钮创建过程。

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace StackoverflowSample
{
public partial class Form1 : Form
{
    private Button myButton;
    /// <summary>
    /// Borrowed code snippet for custom border: http://stackoverflow.com/q/5092216. Would have preferred no to do dllimport yet, but will let it pass this time.
    /// </summary>
    /// <param name="nLeftRect"></param>
    /// <param name="nTopRect"></param>
    /// <param name="nRightRect"></param>
    /// <param name="nBottomRect"></param>
    /// <param name="nWidthEllipse"></param>
    /// <param name="nHeightEllipse"></param>
    /// <returns></returns>
    [DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
    private static extern IntPtr CreateRoundRectRgn
    (
        int nLeftRect, // x-coordinate of upper-left corner
        int nTopRect, // y-coordinate of upper-left corner
        int nRightRect, // x-coordinate of lower-right corner
        int nBottomRect, // y-coordinate of lower-right corner
        int nWidthEllipse, // height of ellipse
        int nHeightEllipse // width of ellipse
     );
    public Form1()
    {
        InitializeComponent();
        this.BackColor = Color.White;
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
        Region = System.Drawing.Region.FromHrgn(CreateRoundRectRgn(0, 0, 0, 0, 0, 0)); // Since our form is dynamically created and/or filled and auto sized, set starting values here to 0.
        Region.MakeInfinite(); // This one was my own, to solve size problems with my dynamically created forms auto size, further reading required for other ways to do it.
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        Font font = new System.Drawing.Font("Meiryo UI", 16.0f);
        myButton = new Button();
        myButton.Name = "tstButton";
        myButton.Size = new Size(50, 50);
        myButton.Location = new Point(10, 10);
        myButton.Font = font;
        myButton.Text = "Test Button";
        myButton.Click += (sender2, e2) => { ButtonClick(sender, e); };
        this.Controls.Add(myButton);
    }
    private void ButtonClick(object sender, EventArgs e)
    {
        Font font = new System.Drawing.Font("Meiryo UI", 16.0f);
        Button myButton = (sender as Button);
        Form myForm = new Form();
        Label row1Label = new Label();
        Label row2Label = new Label();
        Label row3Label = new Label();
        Label row4Label = new Label();
        Label row5Label = new Label();
        row2Label.AutoSize = true;
        row2Label.Text = "Row 1: ";
        row2Label.Font = font;
        row2Label.Location = new Point(5, 5);
        row1Label.AutoSize = true;
        row1Label.Text = "Row 2: ";
        row1Label.Font = font;
        row1Label.Location = new Point(5, 35);
        row3Label.AutoSize = true;
        row3Label.Text = "Row 3: ";
        row3Label.Font = font;
        row3Label.Location = new Point(5, 65);
        row4Label.AutoSize = true;
        row4Label.Text = "Row 4: ";
        row4Label.Font = font;
        row4Label.Location = new Point(5, 95);
        row5Label.AutoSize = true;
        row5Label.Text = "Row 5: ";
        row5Label.Font = font;
        row5Label.Location = new Point(5, 125);
        myForm.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
        myForm.AutoSize = true;
        myForm.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
        myForm.Controls.Add(row1Label);
        myForm.Controls.Add(row2Label);
        myForm.Controls.Add(row3Label);
        myForm.Controls.Add(row4Label);
        myForm.Controls.Add(row5Label);
        myForm.Font = font;
        myForm.BackColor = Color.White;
        myForm.Padding = new System.Windows.Forms.Padding(10, 10, 10, 10);
        myForm.Show();
        myForm.Paint += (sender4, e4) => { Form1_Paint(sender4, e4); }; // Hijacking the borrowed code for custom borders again for the info boxes.
        myForm.Location = new Point(Cursor.Position.X + 25, Cursor.Position.Y - 100); // Create info box a little to the right and up from the cursors position.
        myForm.LostFocus += (sender3, e3) => { CloseForm(sender3, e3, myForm); }; // If the info box loses focus, for example by clicking another button, close that box (form)
        myForm.MouseEnter += (sender3, e3) => { CloseForm(sender3, e3, myForm); }; // Also, if the mouse enters the box, also close, so we can show the buttons under it.
    }
    /// <summary>
    /// Event for closing my "custom" info boxes. Runs at LostFocus or MouseEnter events. So, clicking another button or entering the info box will close it.
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    /// <param name="myForm">Gets the relevant form that the event will run on. Solved my problem of targeting dynamically created forms from outside its scope.</param>
    private void CloseForm(object sender, EventArgs e, Form myForm)
    {
        myForm.Close();
    }
    /// <summary>
    /// Paint event. Holds some borrowed code for getting custom border. Works so far, but further reading required.
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void Form1_Paint(object sender, PaintEventArgs e)
    {
        // Borrowed code snippet for custom border: http://stackoverflow.com/q/5092216
        ControlPaint.DrawBorder(e.Graphics, this.ClientRectangle,
            Color.LightBlue, 5, ButtonBorderStyle.Solid,
            Color.LightBlue, 5, ButtonBorderStyle.Solid,
            Color.LightBlue, 5, ButtonBorderStyle.Solid,
            Color.LightBlue, 5, ButtonBorderStyle.Solid);
    }
}
}

我是一个编程初学者，所以请宽容一些，展示正确的方法，而不是谴责任何糟糕的代码。

亲切的问候,

这张