GridToolTip.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / WinForms / Managed / System / WinForms / PropertyGridInternal / GridToolTip.cs / 1305376 / GridToolTip.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 */ 
namespace System.Windows.Forms.PropertyGridInternal {
    using System.Runtime.Serialization.Formatters; 
    using System.Runtime.InteropServices;
    using System.Runtime.Remoting;
    using System.Diagnostics;
 
    using System;
    using System.Collections; 
 
    using System.Windows.Forms;
    using System.ComponentModel; 
    using System.ComponentModel.Design;
    using System.IO;
    using System.Drawing;
    using Microsoft.Win32; 
    using Message = System.Windows.Forms.Message;
 
    internal class GridToolTip : Control { 

        Control[]    controls; 
        string       toolTipText;
        NativeMethods.TOOLINFO_T[]   toolInfos;
        bool         dontShow;
        Point        lastMouseMove = Point.Empty; 
        private int maximumToolTipLength = 1000;
 
        internal GridToolTip(Control[] controls) { 
            this.controls = controls;
            SetStyle(ControlStyles.UserPaint, false); 
            this.Font = controls[0].Font;
            this.toolInfos = new NativeMethods.TOOLINFO_T[controls.Length];

            for (int i = 0; i < controls.Length; i++) { 
                  controls[i].HandleCreated += new EventHandler(this.OnControlCreateHandle);
                  controls[i].HandleDestroyed += new EventHandler(this.OnControlDestroyHandle); 
 
                  if (controls[i].IsHandleCreated) {
                     SetupToolTip(controls[i]); 
                  }
            }
        }
 
        public string ToolTip{
            get { 
               return toolTipText; 
            }
            set { 
                  if (this.IsHandleCreated || !String.IsNullOrEmpty(value)) {
                      this.Reset();
                  }
 
                  if (value != null && value.Length > maximumToolTipLength)
                  { 
 					  //Let the user know the text was truncated by throwing on an ellipsis 
                      value = value.Substring(0, maximumToolTipLength) + "...";
                  } 
                  this.toolTipText = value;

                  if (this.IsHandleCreated) {
 
                     bool visible = this.Visible;
 
                     if (visible){ 
                        this.Visible = false;
                     } 

                     // here's a hack.  if we give
                     // the tooltip an empty string, it won't come back
                     // so we just force it hidden instead 
                     //
                     if (value == null || value.Length == 0){ 
                        dontShow = true; 
                        value = "";
                     } 
                     else{
                        dontShow = false;
                     }
 
                     for (int i = 0; i < controls.Length; i++) {
                        UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), NativeMethods.TTM_UPDATETIPTEXT, 0, GetTOOLINFO(controls[i])); 
                     } 

                     if (visible && !dontShow){ 
                        this.Visible = true;
                     }

               } 
            }
        } 
 

        ///  
        /// 
        ///     The createParams to create the window.
        /// 
        ///  
        protected override  CreateParams CreateParams {
            get { 
                NativeMethods.INITCOMMONCONTROLSEX icc = new NativeMethods.INITCOMMONCONTROLSEX(); 
                icc.dwICC = NativeMethods.ICC_TAB_CLASSES;
                SafeNativeMethods.InitCommonControlsEx(icc); 
                CreateParams cp = new CreateParams();
                cp.Parent = IntPtr.Zero;
                cp.ClassName = NativeMethods.TOOLTIPS_CLASS;
                cp.Style |= (NativeMethods.TTS_ALWAYSTIP | NativeMethods.TTS_NOPREFIX); 
                cp.ExStyle = 0;
                cp.Caption = this.ToolTip; 
                return cp; 
            }
        } 

        private NativeMethods.TOOLINFO_T GetTOOLINFO(Control c) {

            int index = Array.IndexOf(controls, c); 

            Debug.Assert(index != -1, "Failed to find control in tooltip array"); 
 
            if (toolInfos[index] == null){
               toolInfos[index] = new NativeMethods.TOOLINFO_T(); 
               toolInfos[index].cbSize = Marshal.SizeOf(typeof(NativeMethods.TOOLINFO_T));
               toolInfos[index].uFlags |= NativeMethods.TTF_IDISHWND | NativeMethods.TTF_TRANSPARENT | NativeMethods.TTF_SUBCLASS;
            }
            toolInfos[index].lpszText = this.toolTipText; 
            toolInfos[index].hwnd = c.Handle;
            toolInfos[index].uId = c.Handle; 
            return toolInfos[index]; 
        }
 
        /*
        private bool MouseMoved(Message msg){
            bool moved = true;
 
            Point newMove = new Point(NativeMethods.Util.LOWORD(msg.LParam), NativeMethods.Util.HIWORD(msg.LParam));
 
            // check if the mouse has actually moved... 
            if (lastMouseMove == newMove){
                  moved = false; 
            }

            lastMouseMove = newMove;
            return moved; 
        }
        */ 
 
        private void OnControlCreateHandle(object sender, EventArgs e){
            SetupToolTip((Control)sender); 
        }

        private void OnControlDestroyHandle(object sender, EventArgs e){
            if (IsHandleCreated) { 
                UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), NativeMethods.TTM_DELTOOL, 0, GetTOOLINFO((Control)sender));
            } 
        } 

        protected override void OnHandleCreated(EventArgs e) { 
            base.OnHandleCreated(e);
            for (int i = 0; i < controls.Length; i++) {
                  if (controls[i].IsHandleCreated) {
                     SetupToolTip(controls[i]); 
                  }
            } 
        } 

        private void SetupToolTip(Control c) { 
            if (this.IsHandleCreated) {
               SafeNativeMethods.SetWindowPos(new HandleRef(this, Handle), NativeMethods.HWND_TOPMOST,
                                 0, 0, 0, 0,
                                 NativeMethods.SWP_NOMOVE | NativeMethods.SWP_NOSIZE | 
                                 NativeMethods.SWP_NOACTIVATE);
 
               if (0 == (int)UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), NativeMethods.TTM_ADDTOOL, 0, GetTOOLINFO(c))) { 
                     Debug.Fail("TTM_ADDTOOL failed for " + c.GetType().Name);
               } 

               // Setting the max width has the added benefit of enabling multiline
               // tool tips! subhag 66503)
               // 
               UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), NativeMethods.TTM_SETMAXTIPWIDTH, 0, SystemInformation.MaxWindowTrackSize.Width);
            } 
        } 

        public void Reset(){ 
            // okay, this resets the tooltip state,
            // which can get broken when we leave the window
            // then reenter.  So we set the tooltip to null,
            // update the text, then it back to what it was, so the tooltip 
            // thinks it's back in the regular state again
            // 
            string oldText = this.ToolTip; 
            this.toolTipText = "";
            for (int i = 0; i < controls.Length; i++) { 
               if (0 == (int)UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), NativeMethods.TTM_UPDATETIPTEXT, 0, GetTOOLINFO(controls[i]))) {
                    //Debug.Fail("TTM_UPDATETIPTEXT failed for " + controls[i].GetType().Name);
               }
            } 
            this.toolTipText = oldText;
            this.SendMessage(NativeMethods.TTM_UPDATE, 0, 0); 
        } 

        protected override void WndProc(ref Message msg) { 
            switch (msg.Msg) {
               case NativeMethods.WM_SHOWWINDOW:
                  if (unchecked( (int) (long)msg.WParam) != 0 && dontShow){
                     msg.WParam = IntPtr.Zero; 
                  }
                  break; 
               case NativeMethods.WM_NCHITTEST: 
                  // Fix for VSWhidbey#93985 and VSWhidbey#172903. When using v6 common controls, the native
                  // tooltip does not end up returning HTTRANSPARENT all the time, so its TTF_TRANSPARENT 
                  // behavior does not work, ie. mouse events do not fall thru to controls underneath. This
                  // is due to a combination of old app-specific hacks in comctl32, functional changes between
                  // v5 and v6, and the specfic way the property grid drives its tooltip. Workaround is to just
                  // force HTTRANSPARENT all the time. 
                  msg.Result = (IntPtr) NativeMethods.HTTRANSPARENT;
                  return; 
            } 
            base.WndProc(ref msg);
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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GridToolTip.cs source code in C# .NET

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