How to toggle/switch Windows taskbar from “show” to “auto-hide” (and vice-versa)?

Question

Basically I want to make simple toggle program (that will be mapped to some keyboard shortcut) that set taskbar to auto-hide mode if in normal mode (and conversely, to normal sh

Answer 1

I followed @Quispie answer but it didn't worked at first in Windows 10, but gave me the foundation and source to solve it (so kudos) and also http://www.pinvoke.net/.

[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern IntPtr FindWindow(string strClassName, string strWindowName);

[DllImport("shell32.dll")]
public static extern UInt32 SHAppBarMessage(UInt32 dwMessage, ref APPBARDATA pData);

public enum AppBarMessages
{
    New = 0x00,
    Remove = 0x01,
    QueryPos = 0x02,
    SetPos = 0x03,
    GetState = 0x04,
    GetTaskBarPos = 0x05,
    Activate = 0x06,
    GetAutoHideBar = 0x07,
    SetAutoHideBar = 0x08,
    WindowPosChanged = 0x09,
    SetState = 0x0a
}

[StructLayout(LayoutKind.Sequential)]
public struct APPBARDATA
{
    public int cbSize; // initialize this field using: Marshal.SizeOf(typeof(APPBARDATA));
    public IntPtr hWnd;
    public uint uCallbackMessage;
    public uint uEdge;
    public RECT rc;
    public int lParam;
}

[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
    public int Left, Top, Right, Bottom;

    public RECT(int left, int top, int right, int bottom)
    {
        Left = left;
        Top = top;
        Right = right;
        Bottom = bottom;
    }

    public RECT(System.Drawing.Rectangle r) : this(r.Left, r.Top, r.Right, r.Bottom) { }

    public int X
    {
        get { return Left; }
        set { Right -= (Left - value); Left = value; }
    }

    public int Y
    {
        get { return Top; }
        set { Bottom -= (Top - value); Top = value; }
    }

    public int Height
    {
        get { return Bottom - Top; }
        set { Bottom = value + Top; }
    }

    public int Width
    {
        get { return Right - Left; }
        set { Right = value + Left; }
    }

    public System.Drawing.Point Location
    {
        get { return new System.Drawing.Point(Left, Top); }
        set { X = value.X; Y = value.Y; }
    }

    public System.Drawing.Size Size
    {
        get { return new System.Drawing.Size(Width, Height); }
        set { Width = value.Width; Height = value.Height; }
    }

    public static implicit operator System.Drawing.Rectangle(RECT r)
    {
        return new System.Drawing.Rectangle(r.Left, r.Top, r.Width, r.Height);
    }

    public static implicit operator RECT(System.Drawing.Rectangle r)
    {
        return new RECT(r);
    }

    public static bool operator ==(RECT r1, RECT r2)
    {
        return r1.Equals(r2);
    }

    public static bool operator !=(RECT r1, RECT r2)
    {
        return !r1.Equals(r2);
    }

    public bool Equals(RECT r)
    {
        return r.Left == Left && r.Top == Top && r.Right == Right && r.Bottom == Bottom;
    }

    public override bool Equals(object obj)
    {
        if (obj is RECT)
            return Equals((RECT)obj);
        else if (obj is System.Drawing.Rectangle)
            return Equals(new RECT((System.Drawing.Rectangle)obj));
        return false;
    }

    public override int GetHashCode()
    {
        return ((System.Drawing.Rectangle)this).GetHashCode();
    }

    public override string ToString()
    {
        return string.Format(System.Globalization.CultureInfo.CurrentCulture, "{{Left={0},Top={1},Right={2},Bottom={3}}}", Left, Top, Right, Bottom);
    }
}


public enum AppBarStates
{
    AlwaysOnTop = 0x00,
    AutoHide = 0x01
}

/// 

/// Set the Taskbar State option
/// 
/// AppBarState to activate
public void SetTaskbarState(AppBarStates option)
{
    APPBARDATA msgData = new APPBARDATA();
    msgData.cbSize = Marshal.SizeOf(msgData);
    msgData.hWnd = FindWindow("System_TrayWnd", null);
    msgData.lParam = (int)option;
    SHAppBarMessage((UInt32)AppBarMessages.SetState, ref msgData);
}

/// 

/// Gets the current Taskbar state
/// 
/// current Taskbar state
public AppBarStates GetTaskbarState()
{
    APPBARDATA msgData = new APPBARDATA();
    msgData.cbSize = Marshal.SizeOf(msgData);
    msgData.hWnd = FindWindow("System_TrayWnd", null);
    return (AppBarStates)SHAppBarMessage((UInt32)AppBarMessages.GetState, ref msgData);
}