WindowsListViewScroll.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / UIAutomation / Win32Providers / MS / Internal / AutomationProxies / WindowsListViewScroll.cs / 1305600 / WindowsListViewScroll.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: Class to provide scroll bars for listview 
//
// History: 
//        Jean-Francois Peyroux (in DotNet)
//        2003/08/08 - alexsn Updated for WCP
//        2004/08/19 - preid Took this out of the class hierarchy for listview and made the
//                     non-client area use to create the scroll bar children 
//
//--------------------------------------------------------------------------- 
 
using System;
using System.Runtime.InteropServices; 
using System.ComponentModel;
using System.Windows.Automation;
using System.Windows.Automation.Provider;
using System.Windows; 
using MS.Win32;
 
namespace MS.Internal.AutomationProxies 
{
 
        // The default implementation for scroll bars uses SB_THUMBTRACK and SB_THUMBPOSITION for SetValue
        // This does not work with listview so the Scrollbar is overloaded with a derived version that
        // uses LVM_SCROLL messages instead
        class WindowsListViewScrollBar: WindowsScrollBar, IRangeValueProvider 
        {
 
            // ----------------------------------------------------- 
            //
            //  Constructors 
            //
            //-----------------------------------------------------

            #region Constructors 

            internal WindowsListViewScrollBar(IntPtr hwnd, ProxyFragment parent, int item, int sbFlag) 
                : base( hwnd, parent, item, sbFlag){} 

            #endregion Constructors 

            //------------------------------------------------------
            //
            //  Patterns Implementation 
            //
            //----------------------------------------------------- 
 
            #region RangeValue Pattern
 
            void IRangeValueProvider.SetValue(double val)
            {
                // Check if the window is disabled
                if (!SafeNativeMethods.IsWindowEnabled (_hwnd)) 
                {
                    throw new ElementNotEnabledException(); 
                } 

                NativeMethods.ScrollInfo si = new NativeMethods.ScrollInfo (); 
                si.fMask = NativeMethods.SIF_ALL;
                si.cbSize = Marshal.SizeOf (si.GetType ());

                if (!Misc.GetScrollInfo(_hwnd, _sbFlag, ref si)) 
                {
                    return; 
                } 

                int pos = (int)val; 
                // Throw if val is greater than the maximum or less than the minimum.
                // See remarks for WindowsScrollBar.GetScrollValue(ScrollBarInfo.MaximumPosition)
                // regarding this calculation of the allowed maximum.
                if (pos > si.nMax - si.nPage + (si.nPage > 0 ? 1 : 0)) 
                {
                    throw new ArgumentOutOfRangeException("value", val, SR.Get(SRID.RangeValueMax)); 
                } 
                else if (pos < si.nMin)
                { 
                    throw new ArgumentOutOfRangeException("value", val, SR.Get(SRID.RangeValueMin));
                }

                // LVM_SCROLL does not work in mode Report, use SetScrollPos instead 
                bool isVerticalScroll = IsScrollBarVertical(_hwnd, _sbFlag);
                if (isVerticalScroll && WindowsListView.InReportView (_hwnd)) 
                { 
                    Misc.SetScrollPos(_hwnd, _sbFlag, pos, true);
                    return; 
                }

                // get the "full size" of the list-view
                int size = WindowsListView.ApproximateViewRect (_hwnd); 

                // delta between current and user-requested position in pixels 
                // since the cPelsAll contains the dimension in pels for all items + the 2 pels of the border 
                // the operation below does a trunc on purpose
                int dx = 0, dy = 0; 
                if (!isVerticalScroll)
                {
                    int cPelsAll = NativeMethods.Util.LOWORD (size);
 
                    dx = (int)((pos - si.nPos) * ((double)cPelsAll / (si.nMax + 1 - si.nMin)));
                } 
                else 
                {
                    int cPelsAll = NativeMethods.Util.HIWORD (size); 

                    dy = (int)((pos - si.nPos) * ((double)cPelsAll / (si.nMax + 1 - si.nMin)));
                }
 
                if (WindowsListView.Scroll (_hwnd, (IntPtr) dx, (IntPtr) dy))
                { 
                    // Check the result, on occasion the result will be different to given value 
                    // a-jeanp: I played a lot to figure out what it is not the case.
                    // I am giving up and issuing instead a second call with a new delta. 
                    if (!Misc.GetScrollInfo(_hwnd, _sbFlag, ref si))
                    {
                        return;
                    } 

                    if (si.nPos != pos) 
                    { 
                        if (!isVerticalScroll)
                        { 
                            int cPelsAll = NativeMethods.Util.LOWORD (size);

                            dx = (pos - si.nPos) * (cPelsAll / (si.nMax + 1 - si.nMin));
                        } 
                        else
                        { 
                            int cPelsAll = NativeMethods.Util.HIWORD (size); 

                            dy = (pos - si.nPos) * (cPelsAll / (si.nMax + 1 - si.nMin)); 
                        }

                        WindowsListView.Scroll (_hwnd, (IntPtr) dx, (IntPtr) dy);
                    } 
                }
            } 
 
            #endregion Value Pattern
 
    }
}

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

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