C MDI open subform to remove automatically generated menu bar

C# stay DMI The menu bar is automatically generated when the subform is opened in , How to remove the menu bar ？

First open the child form in the load event of the parent form and maximize it

private void MDIParent1_Load(object sender, EventArgs e)
        {
            firstPage();// Open a subform
        }

How to open a subform ：

private void firstPage() {
            splash frm = new splash();// Subform instantiation
            frm.MdiParent = this;// Set the current form as the parent of the child form
            frm.WindowState = FormWindowState.Maximized;// The state of the subform is maximized
            frm.Show();// Display Form
        }

I found a lot on the Internet , Only in use MenuStrip The menu bar can be removed , Use ToolStrip Can't remove the automatically generated menu bar , So in order to use ToolStrip Also remove the menu bar , In the parent form MenuStrip menu bar , To remove the menu bar .

First, in the ToolStrip Add MenuStrip menu bar

add to MenuStrip menu bar Of ItemAdded event

Add... To the automatically generated method

 private void menuStrip1_ItemAdded_1(object sender, ToolStripItemEventArgs e)
        {
      if (e.Item.Text.Length == 0             // Hide subform icons
       || e.Item.Text == " To minimize the (&N)"      // Hide minimize button
       || e.Item.Text == " Restore (&R)"           // Hide restore button
       || e.Item.Text == " close (&C)")         // Hide the close button
            {
                e.Item.Visible = false;
            }
        }

Not even after joining , You need to add this code to the parent form loading event ：

this.MainMenuStrip = menuStrip1;// Set the menu bar of the child form to the menu bar of the parent form

private void MDIParent1_Load(object sender, EventArgs e)
        {
            this.MainMenuStrip = menuStrip1;// Set the menu bar of the child form to the menu bar of the parent form
            firstPage();// Open a subform
        }

When finished, generate , The menu bar is still there , But the icons are all gone ：

This makes me feel twisted , How to solve it ？ Thought of jumping the height of the menu bar to the minimum , However, you cannot directly adjust the height of the menu bar in the properties , So in the loading event, the height of the menu bar is changed ：

Added two lines of code ：

            menuStrip1.AutoSize = false;
            menuStrip1.Size = new Size(100, 1);

private void MDIParent1_Load(object sender, EventArgs e)
        {
            // Set the height of the custom menu bar to 1
            menuStrip1.AutoSize = false;
            menuStrip1.Size = new Size(100, 1);
            this.MainMenuStrip = menuStrip1;// Set the menu bar of the child form to the menu bar of the parent form
            firstPage();
        }

The effect after regeneration :

stay ToolStrip above MenuStrip The menu bar has disappeared ,OK, Problem solving .