如何使winform应用程序全屏并覆盖任务栏

Question

I tried all answers under How do I make a WinForms app go Full Screen and How to display a Windows Form in full screen on top of the taskbar . But they cannot work (means the taskbar is visible).
Setting TopMost = true is a bad way because it cannot switch windows by Alt+Tab.

I thought WindowState = FormWindowState.Maximized is conflicted with AutoSize. (I have set AutoSize to True, and AutoSizeMode to GrowAndShrink to make it adapt to a panel.)

Here's code (note the order of FormBorderStyle= and WindowState=):

public void fullScreenDisplay()
{
    this.currentPanelSize = new Size(this.mainPanel.ClientSize.Width, this.mainPanel.ClientSize.Height);

    this.FormBorderStyle = FormBorderStyle.None;
    //this.TopMost = true;
    //Rectangle ret = Screen.GetWorkingArea(this);
    Rectangle ret = Screen.PrimaryScreen.Bounds;

    this.mainPanel.ClientSize = new Size(ret.Width, ret.Height);
    //this.mainPanel.Dock = DockStyle.Fill;
    this.mainPanel.BringToFront();

    this.WindowState = FormWindowState.Maximized;
}

the code of Designer.cs:

private void InitializeComponent()
{ 
    this.mainPanel = new System.Windows.Forms.Panel();
    this.SuspendLayout();
    // 
    // mainPanel
    // 
    this.mainPanel.Location = new System.Drawing.Point(0, 0);
    this.mainPanel.Margin = new System.Windows.Forms.Padding(0);
    this.mainPanel.Name = "mainPanel";
    this.mainPanel.Size = new System.Drawing.Size(1600, 900);
    this.mainPanel.TabIndex = 0;
    this.mainPanel.Paint += new System.Windows.Forms.PaintEventHandler(this.mainPanel_Paint);
    // 
    // MainForm
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.AutoSize = true;
    this.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
    this.ClientSize = new System.Drawing.Size(120, 0);
    this.Controls.Add(this.mainPanel);
    this.MaximizeBox = false;
    this.Name = "MainForm";
    this.Text = "MainForm";
    this.Load += new System.EventHandler(this.MainForm_Load);
    this.ResumeLayout(false);

}

And I'm working on Windows10.

Answer 1

This is what we are using - we are multi-screen and all of them are full covering taskbar

mainForm.WindowState = FormWindowState.Normal;
mainForm.FormBorderStyle = FormBorderStyle.Sizable;
mainForm.StartPosition = FormStartPosition.Manual;
mainForm.Location = this.SystemScreen.Bounds.Location;
mainForm.FormBorderStyle = FormBorderStyle.None;
mainForm.Size = this.SystemScreen.Bounds.Size;
mainForm.WindowState = FormWindowState.Maximized;

SystemScreen is System.Windows.Forms.Screen

but it's just to get the dimension of the screen You can get your screens with Screen.AllScreens

Answer 2

This goes full screen and over the taskbar for me
(also with AutoSize = true and AutoSizeMode = AutoSizeMode.GrowAndShrink )

public void fullScreenDisplay()
{
    // This is required if the form reaches this code in maximized state
    // otherwise the TaskBar remains on top of the form
    this.WindowState = FormWindowState.Normal;

    this.FormBorderStyle = FormBorderStyle.None;
    this.WindowState = FormWindowState.Maximized;
    this.mainPanel.Dock = DockStyle.Fill;
    this.BringToFront();
}

In other words, don't try to set the dimensions neither for the form and for the panel if you want the get the default behavior. Instead force the Panel to Dock inside the full size of the form.