.

Summary

The ShowWindow API

C# Signature:

[DllImport("user32.dll")]
static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

VB Signature:

<DllImport("user32.dll")> _
Public Shared Function ShowWindow(ByVal hWnd As IntPtr, ByVal nCmdShow As Integer) As Boolean
End Function

Constants:

SW

User-Defined Types:

None.

Notes:

just use it like this to hide the task bar...

ShowWindow(FindWindow("Shell_TrayWnd", null), 0);

Tips & Tricks:

You can get the window handle of a process by using:

System.Diagnostics.Process p = System.Diagnostics.Process.GetProcessById(id);

Then use the MainWindowHandle property when passing to the ShowWindow()

ShowWindow(p.MainWindowHandle, 3); // Maximize this window

Sample Code:

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

using System.Runtime.InteropServices;

namespace hide

{

    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.Button button1;
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;

        public Form1()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();
            Application.EnableVisualStyles();

            //
            // TODO: Add any constructor code after InitializeComponent call
            //
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            //
            // button1
            //
            this.button1.FlatStyle = System.Windows.Forms.FlatStyle.System;
            this.button1.Font = new System.Drawing.Font("Tahoma", 15.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
            this.button1.Location = new System.Drawing.Point(32, 32);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(216, 176);
            this.button1.TabIndex = 0;
            this.button1.Text = "CLICK ME!!";
            this.button1.Click += new System.EventHandler(this.button1_Click);
            //
            // Form1
            //
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.BackColor = System.Drawing.SystemColors.Info;
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);

        }
        #endregion

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.Run(new Form1());
        }

        [DllImport("user32.dll")]
        static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

        [DllImport("user32.dll")]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        bool visable=true;
        private void button1_Click(object sender, System.EventArgs e)
        {
            if(visable)
            {
                this.button1.Text="SHOW";
                ShowWindow(FindWindow("Shell_TrayWnd", null), 0);
                visable=false;
            }
            else if(!visable)
            {
                this.button1.Text="HIDE";
                ShowWindow(FindWindow("Shell_TrayWnd", null), 1);
                visable=true;
            }
        }
    }

}

Alternative Managed API:

Do you know one? Please contribute it!

Documentation

ShowWindow on MSDN