// ToggleButton
   // This class subclasses a CheckBox to combine the benefits of a Checkbox and 
   // Checkbox-with-Button-Appearance by combining a checkbox and button into one control.
   // 
   // Requirements: 
   // [1] Two states (like a checkbox).
   // [2] Visually imply action/control (like a button). 
   //     I think a Checkbox fails this requirement.
   // [3] It should be intuitively obvious what the state is and what the button will do when clicked.
   //     A checkbox meets the state requirement but fails the Action requirement because
   //     checkboxes are typically used for configuration rather than action.
   //     I think a Checkbox-with-button-appearance fails because it's not obvious if the button is depressed or not.
   //     I think a button-with-changing-text fails. Does the text show state or the on-click (oposite) action?
   //     Designers use button-with-changing-text inconsistently.
   // [4] Explicity show State even with poor dispplay visibility. 
   //     I think a Checkbox-with-button-appearance fails this requirement.
   // [5] Works on all resolutions and themes, doesn't look to 'flashy' and must 'fit-in'
   //     I think a 2-bitmapped button would fail this requirement.
   //     Many 3-rd party buttons fail this requirement.
   // 
   // This class uses DrawToBitmap to capture a temporary Checkbox's appearance.
   // It captures just the checkbox without the text.
   // I want to use a standard checkbox to be consistent with system-wide styles.
   //
   // Design usage:
   // [1] Add this class ToggleButton to project.
   // [2] Add 'normal' checkbox to WinForm
   // [3] Change it's class to this ToggleButton class (in both the declaration and instantiation).
   // [4] Set properties...
   //     Appearance = System.Windows.Forms.Appearance.Button;
   //     TextImageRelation = System.Windows.Forms.TextImageRelation.ImageBeforeText;
   //
   // Room for improvement:
   //    Create a user control that's more portable (although it's easy to add a class to a project).
   public class ToggleButton : CheckBox
   {
      //constructor
      public ToggleButton() : base() 
      {
         this.SuspendLayout();
 
         if (bmChecked == null) // If the static bitmaps haven't been constructed, create them.
         {
            System.Windows.Forms.CheckBox chkTemp = new System.Windows.Forms.CheckBox();
 
            chkTemp.AutoSize = true;
            chkTemp.BackColor = System.Drawing.Color.Transparent;
            chkTemp.Location = new System.Drawing.Point(123, 128);
            chkTemp.Name = "chkSmall";
            chkTemp.Size = chkTemp.PreferredSize;
            chkTemp.TabIndex = 2;
            chkTemp.UseVisualStyleBackColor = false;
 
            bmChecked = new Bitmap(chkTemp.Width, chkTemp.Height);
            bmUnChecked = new Bitmap(chkTemp.Width, chkTemp.Height);
            bmDisabled = new Bitmap(chkTemp.Width, chkTemp.Height);
 
            // Set checkbox false and capture bitmap.
            chkTemp.Checked = false;
            chkTemp.DrawToBitmap(bmUnChecked, new Rectangle(0, 0, chkTemp.Width, chkTemp.Height));
 
            // Set checkbox true and capture bitmap.
            chkTemp.Checked = true;
            chkTemp.DrawToBitmap(bmChecked, new Rectangle(0, 0, chkTemp.Width, chkTemp.Height));
 
            // Set checkbox false/disabled and capture bitmap.
            chkTemp.Checked = false;
            chkTemp.Enabled = false;
            chkTemp.DrawToBitmap(bmDisabled, new Rectangle(0, 0, chkTemp.Width, chkTemp.Height));
 
            chkTemp.Visible = false;
 
         }
         this.CheckedChanged += new System.EventHandler(this.btnToggleButton_Changed);
         this.EnabledChanged += new System.EventHandler(this.btnToggleButton_Changed);
         this.Image = this.Checked ? bmChecked : bmUnChecked;
         this.ResumeLayout(false);
         btnToggleButton_Changed(null, null);
      }
 
 
      private void btnToggleButton_Changed(object sender, EventArgs e)
      {
         Image = 
            !Enabled ? bmDisabled :
            Checked  ? bmChecked  : 
            bmUnChecked;
      }
 
      // Create 3 static bitmaps to swap-out when the button changes.
      // Static saves space (we don't need a copy for each instance of this class) but it seemed to break the design-time display.
      private static Bitmap bmChecked;
      private static Bitmap bmUnChecked;
      private static Bitmap bmDisabled;
 
   }