How to prevent flickering in ListView when updating a single ListViewItem's text?

Question

All I want is to update an ListViewItem's text whithout seeing any flickering.

This is my code for updating (called several times):

listView.BeginUpdate();
listViewItem.SubItems[0].Text = state.ToString();    // update the state
listViewItem.SubItems[1].Text = progress.ToString(); // update the progress
listView.EndUpdate();

I've seen some solutions that involve overriding the component's WndProc():

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == (int)WM.WM_ERASEBKGND)
        {
            m.Msg = (int)IntPtr.Zero;
        }
        base.WndProc(ref m);
    }

They say it solves the problem, but in my case It didn't. I believe this is because I'm using icons on every item.

Answer 1

If you only want to update the text, simply set the changed SubItem's text directly rather than updating the entire ListViewItem (you've not said how you're doing your updates).

The override you show is equivalent to simply overriding OnPaintBackground, which would be a "more correct" managed way to do that task, and it's not going to help for a single item.

If you still have problems, we'll need clarification on what you've actually tried.

Answer 2

This is a shot in the dark, but you could try double buffering the control.

SetStyle(
  ControlStyles.AllPaintingInWmPaint |
  ControlStyles.UserPaint |
  ControlStyles.DoubleBuffer, true)

Answer 3

The ListView in CommonControls 6 (XP or newer) supports double buffering. Fortunately, .NET wraps the newest CommonControls on the system. To enable double buffering, send the appropriate Windows message to the ListView control.

Here are the details: http://www.codeproject.com/KB/list/listviewxp.aspx

Answer 4

To end this question, here is a helper class that should be called when the form is loading for each ListView or any other ListView's derived control in your form. Thanks to "Brian Gillespie" for giving the solution.

public enum ListViewExtendedStyles
{
    /// <summary>
    /// LVS_EX_GRIDLINES
    /// </summary>
    GridLines = 0x00000001,
    /// <summary>
    /// LVS_EX_SUBITEMIMAGES
    /// </summary>
    SubItemImages = 0x00000002,
    /// <summary>
    /// LVS_EX_CHECKBOXES
    /// </summary>
    CheckBoxes = 0x00000004,
    /// <summary>
    /// LVS_EX_TRACKSELECT
    /// </summary>
    TrackSelect = 0x00000008,
    /// <summary>
    /// LVS_EX_HEADERDRAGDROP
    /// </summary>
    HeaderDragDrop = 0x00000010,
    /// <summary>
    /// LVS_EX_FULLROWSELECT
    /// </summary>
    FullRowSelect = 0x00000020,
    /// <summary>
    /// LVS_EX_ONECLICKACTIVATE
    /// </summary>
    OneClickActivate = 0x00000040,
    /// <summary>
    /// LVS_EX_TWOCLICKACTIVATE
    /// </summary>
    TwoClickActivate = 0x00000080,
    /// <summary>
    /// LVS_EX_FLATSB
    /// </summary>
    FlatsB = 0x00000100,
    /// <summary>
    /// LVS_EX_REGIONAL
    /// </summary>
    Regional = 0x00000200,
    /// <summary>
    /// LVS_EX_INFOTIP
    /// </summary>
    InfoTip = 0x00000400,
    /// <summary>
    /// LVS_EX_UNDERLINEHOT
    /// </summary>
    UnderlineHot = 0x00000800,
    /// <summary>
    /// LVS_EX_UNDERLINECOLD
    /// </summary>
    UnderlineCold = 0x00001000,
    /// <summary>
    /// LVS_EX_MULTIWORKAREAS
    /// </summary>
    MultilWorkAreas = 0x00002000,
    /// <summary>
    /// LVS_EX_LABELTIP
    /// </summary>
    LabelTip = 0x00004000,
    /// <summary>
    /// LVS_EX_BORDERSELECT
    /// </summary>
    BorderSelect = 0x00008000,
    /// <summary>
    /// LVS_EX_DOUBLEBUFFER
    /// </summary>
    DoubleBuffer = 0x00010000,
    /// <summary>
    /// LVS_EX_HIDELABELS
    /// </summary>
    HideLabels = 0x00020000,
    /// <summary>
    /// LVS_EX_SINGLEROW
    /// </summary>
    SingleRow = 0x00040000,
    /// <summary>
    /// LVS_EX_SNAPTOGRID
    /// </summary>
    SnapToGrid = 0x00080000,
    /// <summary>
    /// LVS_EX_SIMPLESELECT
    /// </summary>
    SimpleSelect = 0x00100000
}

public enum ListViewMessages
{
    First = 0x1000,
    SetExtendedStyle = (First + 54),
    GetExtendedStyle = (First + 55),
}

/// <summary>
/// Contains helper methods to change extended styles on ListView, including enabling double buffering.
/// Based on Giovanni Montrone's article on <see cref="http://www.codeproject.com/KB/list/listviewxp.aspx"/&gt;
/// </summary>
public class ListViewHelper
{
    private ListViewHelper()
    {
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern int SendMessage(IntPtr handle, int messg, int wparam, int lparam);

    public static void SetExtendedStyle(Control control, ListViewExtendedStyles exStyle)
    {
        ListViewExtendedStyles styles;
        styles = (ListViewExtendedStyles)SendMessage(control.Handle, (int)ListViewMessages.GetExtendedStyle, 0, 0);
        styles |= exStyle;
        SendMessage(control.Handle, (int)ListViewMessages.SetExtendedStyle, 0, (int)styles);
    }

    public static void EnableDoubleBuffer(Control control)
    {
        ListViewExtendedStyles styles;
        // read current style
        styles = (ListViewExtendedStyles)SendMessage(control.Handle, (int)ListViewMessages.GetExtendedStyle, 0, 0);
        // enable double buffer and border select
        styles |= ListViewExtendedStyles.DoubleBuffer | ListViewExtendedStyles.BorderSelect;
        // write new style
        SendMessage(control.Handle, (int)ListViewMessages.SetExtendedStyle, 0, (int)styles);
    }
    public static void DisableDoubleBuffer(Control control)
    {
        ListViewExtendedStyles styles;
        // read current style
        styles = (ListViewExtendedStyles)SendMessage(control.Handle, (int)ListViewMessages.GetExtendedStyle, 0, 0);
        // disable double buffer and border select
        styles -= styles & ListViewExtendedStyles.DoubleBuffer;
        styles -= styles & ListViewExtendedStyles.BorderSelect;
        // write new style
        SendMessage(control.Handle, (int)ListViewMessages.SetExtendedStyle, 0, (int)styles);
    }
}

Answer 5

In .NET Winforms 2.0 there exist a protected property called DoubleBuffered.

By inheriting from ListView, then one can set this protected property to true. This will enable double buffering without needing to call SendMessage.