Question

我正在做一场比赛。我有一个用户列表（缺口）：

List<string> users;

此列表用于向ListBox上的用户显示，请致电listaJogadores。

    public delegate void actualizaPlayersCallback(List<string> users);

    public void actualizaPlayers(List<string> users)
    {
        listaJogadores.BeginInvoke(new actualizaPlayersCallback(this.actualizarListaPlayers), new object[] { users });
    }

    public void actualizarListaPlayers(List<string> users)
    {
        listaJogadores.Items.Clear();
        for (int i = 0; i < users.Count; i++)
        {
            listaJogadores.Items.Add(users.ElementAt(i));
        }         
    }

当用户正在玩游戏时，它在游戏列表中有缺口：

List<Game> games;

我想要的是当玩家进入游戏时，listaJogadores中的昵称颜色必须为红色！当我在游戏中只有一个玩家时，一切正常，所有玩家都看到该玩家的昵称是红色的，但当另一个玩家进入游戏时，我在指令中得到 ArgumentOutOfRangeException string nick = tmp.players.ElementAt(i).getNick();

这是我的代码......请给我一些想法/帮助！我认为问题是for()，但是如何在不进行循环的情况下操纵整个列表呢？

listaJogadores.DrawMode = DrawMode.OwnerDrawFixed;

private void listaJogadores_DrawItem(object sender, DrawItemEventArgs e)
    {
        e.DrawBackground();
        Brush textBrush = SystemBrushes.ControlText;
        Font drawFont = e.Font;

        for (int i = 0; i < games.Count; i++)
        {
            Game tmp;
            tmp = games.ElementAt(i);
            for (int j = 0; j < tmp.players.Count; j++)
            {
                string nick = tmp.players.ElementAt(i).getNick();

                if (listaJogadores.Items[e.Index].ToString() == nick)
                {
                    textBrush = Brushes.Red;//RED....
                    if ((e.State & DrawItemState.Selected) > 0)
                        drawFont = new Font(drawFont.FontFamily, drawFont.Size, FontStyle.Bold);
                }
                else if ((e.State & DrawItemState.Selected) > 0)
                {
                    textBrush = SystemBrushes.HighlightText;
                }
            }
        }
        e.Graphics.DrawString(listaJogadores.Items[e.Index].ToString(), drawFont, textBrush, e.Bounds);
    }

Answer 1

您不应该在循环中放置绘图逻辑，因为您只想定义画笔一次。首先确定该项目是否是实际游戏中的玩家。然后用正确的颜色绘制项目：

private void listaJogadores_DrawItem(object sender, DrawItemEventArgs e)
{
    if (e.Index >= 0 && e.Index < listaJogadores.Items.Count) {
        e.DrawBackground();
        Brush textBrush = SystemBrushes.ControlText;
        Font drawFont = e.Font;
        bool playerFound = false;
        string nick = (string)listaJogadores.Items[e.Index];
        foreach (Game game in games) {
            if (game.players.Any(p => p.getNick() == nick)) {
                playerFound = true;
                break;
            }
        }
        if (playerFound) {
            textBrush = Brushes.Red;  //RED....  
            if ((e.State & DrawItemState.Selected) > 0)
                drawFont = new Font(drawFont.FontFamily, drawFont.Size, FontStyle.Bold);
        } else if ((e.State & DrawItemState.Selected) > 0) {
            textBrush = SystemBrushes.HighlightText;
        }
        e.Graphics.DrawString(nick, drawFont, textBrush, e.Bounds);
        e.DrawFocusRectangle();
    }
}

并测试e.Index是否有效。这可能会导致您的“索引超出范围”异常。

Answer 2

检查此代码：

private void listaJogadores_DrawItem(object sender, DrawItemEventArgs e)
{
    listaJogadores.DrawItem-=Eeventhandle(listaJogadores_DrawItem);
    .
    .
    .
    listaJogadores.DrawItem+=Eeventhandle(listaJogadores_DrawItem);
}

如何在ListBox单个元素中设置前景色？

2 个答案: