ToolStripScrollButton.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / ToolStripScrollButton.cs / 1 / ToolStripScrollButton.cs
                        
                        
                            //------------------------------------------------------------------------------
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
//  
//-----------------------------------------------------------------------------
 
 
namespace System.Windows.Forms {
    using System; 
    using System.ComponentModel;
    using System.Drawing;
    using System.Drawing.Design;
    using System.Diagnostics; 
    using System.Windows.Forms.ButtonInternal;
    using System.Security.Permissions; 
    using System.Security; 

 
    /// 
    /// 
    /// A non selectable winbar item
    ///  
    internal class ToolStripScrollButton : ToolStripControlHost {
        private bool up = true; 
 
        [ThreadStatic]
        private static Bitmap upScrollImage; 

        [ThreadStatic]
        private static Bitmap downScrollImage;
 
        const int AUTOSCROLL_UPDATE = 50;
        private static readonly int AUTOSCROLL_PAUSE = SystemInformation.DoubleClickTime; 
 

        private Timer mouseDownTimer; 

        public ToolStripScrollButton(bool up) : base(CreateControlInstance(up)) {
            this.up = up;
        } 

 
        private static Control CreateControlInstance(bool up) { 
            StickyLabel label = new StickyLabel();
            label.ImageAlign = ContentAlignment.MiddleCenter; 
            label.Image = (up) ? UpImage : DownImage;
            return label;
        }
 
         /// 
         /// Deriving classes can override this to configure a default size for their control. 
         /// This is more efficient than setting the size in the control's constructor. 
         /// 
         protected internal override Padding DefaultMargin { 
             get {
                 return Padding.Empty;
             }
         } 
         protected override Padding DefaultPadding {
             get { 
                 return Padding.Empty; 
             }
         } 

         private static Image DownImage {
            get {
                if (downScrollImage == null) { 
                      downScrollImage = new Bitmap(typeof(ToolStripScrollButton), "ScrollButtonDown.bmp");
                      downScrollImage.MakeTransparent(Color.White); 
 
                }
                return downScrollImage; 
            }
        }

 
        internal StickyLabel Label {
            get{ 
                return Control as StickyLabel; 
            }
        } 

        private static Image UpImage {
            get {
                if (upScrollImage == null) { 
                      upScrollImage = new Bitmap(typeof(ToolStripScrollButton), "ScrollButtonUp.bmp");
                      upScrollImage.MakeTransparent(Color.White); 
 
                }
                return upScrollImage; 
            }
        }

        private Timer MouseDownTimer { 
            get{
                if (mouseDownTimer == null) { 
                    mouseDownTimer = new Timer(); 
                }
                return mouseDownTimer; 
            }
        }

        protected override void Dispose(bool disposing) { 
            if (disposing) {
                if (mouseDownTimer != null) { 
                    mouseDownTimer.Enabled = false; 
                    mouseDownTimer.Dispose();
                    mouseDownTimer = null; 
                }
            }
            base.Dispose(disposing);
        } 
        protected override void OnMouseDown (MouseEventArgs e) {
            UnsubscribeAll(); 
 
            base.OnMouseDown(e);
            Scroll(); 

            MouseDownTimer.Interval =  AUTOSCROLL_PAUSE;
            MouseDownTimer.Tick += new EventHandler(OnInitialAutoScrollMouseDown);
            MouseDownTimer.Enabled = true; 
        }
 
        protected override void OnMouseUp (MouseEventArgs e) { 
            UnsubscribeAll();
            base.OnMouseUp(e); 
        }

        protected override void  OnMouseLeave (EventArgs e) {
            UnsubscribeAll(); 
        }
        private void UnsubscribeAll() { 
            MouseDownTimer.Enabled = false; 
            MouseDownTimer.Tick -= new EventHandler(OnInitialAutoScrollMouseDown);
            MouseDownTimer.Tick -= new EventHandler(OnAutoScrollAccellerate); 
        }

        private void OnAutoScrollAccellerate(object sender, EventArgs e) {
            Scroll(); 
        }
 
        private void OnInitialAutoScrollMouseDown(object sender, EventArgs e)  { 
            MouseDownTimer.Tick -= new EventHandler(OnInitialAutoScrollMouseDown);
 
            Scroll();
            MouseDownTimer.Interval =  AUTOSCROLL_UPDATE;
            MouseDownTimer.Tick += new EventHandler(OnAutoScrollAccellerate);
        } 

        public override Size GetPreferredSize(Size constrainingSize) { 
            Size preferredSize = Size.Empty; 
            preferredSize.Height = (Label.Image != null) ? Label.Image.Height + 4 : 0;
            preferredSize.Width = (ParentInternal != null) ? ParentInternal.Width - 2 : preferredSize.Width; // Two for border 
            return preferredSize;
        }

        private void Scroll() { 
            ToolStripDropDownMenu parent = this.ParentInternal as ToolStripDropDownMenu;
            if (parent != null && Label.Enabled) { 
                parent.ScrollInternal(up); 
            }
        } 

        internal class StickyLabel : Label {

            public StickyLabel() { 
            }
            private bool freezeLocationChange = false; 
 
            public bool FreezeLocationChange {
              get { return freezeLocationChange; } 
            }

            protected override void SetBoundsCore(int x,int y,int width, int height, BoundsSpecified specified)
            { 
                if (((specified & BoundsSpecified.Location) != 0) && FreezeLocationChange) {
                    return; 
                } 
                base.SetBoundsCore(x, y, width, height, specified);
            } 

            [SecurityPermission(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)]
            protected override void WndProc(ref Message m) {
 
                if (m.Msg >= NativeMethods.WM_KEYFIRST && m.Msg <= NativeMethods.WM_KEYLAST) {
                    // SECREVIEW: 
                    // NOTE this is the same as ToolStripDropDown, except we NEVER want to raise the key events. 
                    DefWndProc(ref m);
                    return; 
                }

                base.WndProc(ref m);
            } 
        }
    } 
} 

 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ToolStripScrollButton.cs source code in C# .NET

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