是否有可能通过检查类的值来循环遍历ListBox中的项目并以某种方式突出显示或指示项目不可用?
[基本上,有一个Game类,并且在存储的信息中是否有可用的Game,所以我在遍历ListBox项时需要检查此类,并以某种方式在ListBox上指示GameAvailable = false。
到此为止,不确定如何进行:
private void HighlightUnavailable()
{
foreach(string item in listbox_consoles.Items)
{
foreach (Products.Game game in GameService.AllGames())
{
if (item == game.GameName.ToString())
{
if (game.GameAvailable)
{
}
}
}
}
}
是的,可以这样:
将列表框绑定到GameService.AllGames()
,它返回Game
对象的列表或数组。
将ListBox.DrawMode设置为DrawMode.OwnerDrawFixed
并处理ListBox.DrawItem事件以根据其GameAvailable
属性绘制项目。
假设控件名称是Form1
和listBox1
,请添加Form1
构造函数:
public Form1()
{
InitializeComponent();
//...
listBox1.DrawMode = DrawMode.OwnerDrawFixed;
listBox1.DrawItem += (s, e) => OnListBoxDrawItem(s, e);
}
假设您要以绿色显示可用的游戏,其余以红色前景色显示。
private void OnListBoxDrawItem(object sender, DrawItemEventArgs e)
{
//Comment if you don't need to show the selected item(s)...
e.DrawBackground();
if (e.Index == -1) return;
var game = listBox1.Items[e.Index] as Game;
var foreColor = game.GameAvailable ? Color.Green : Color.Red;
//Pass the listBox1.BackColor instead of the e.BackColor
//if you don't need to show the selection...
TextRenderer.DrawText(e.Graphics, game.GameName, e.Font,
e.Bounds, foreColor, e.BackColor,
TextFormatFlags.Left | TextFormatFlags.VerticalCenter);
}
...或具有不同的背景色:
private void OnListBoxDrawItem(object sender, DrawItemEventArgs e)
{
if (e.Index == -1) return;
var game = listBox1.Items[e.Index] as Game;
var backColor = e.State.HasFlag(DrawItemState.Selected)
? e.BackColor
: game.GameAvailable
? Color.LightGreen
: listBox1.BackColor;
//Or this if you don't need to show the selection ...
//var backColor = game.GameAvailable
// ? Color.LightGreen
// : listBox1.BackColor;
using (var br = new SolidBrush(backColor))
e.Graphics.FillRectangle(br, e.Bounds);
TextRenderer.DrawText(e.Graphics, game.GameName, e.Font,
e.Bounds, Color.Black, backColor,
TextFormatFlags.Left | TextFormatFlags.VerticalCenter);
}
...或带有来自您资源的一些是/否图像:
Bitmap YesImage, NoImage;
public Form1()
{
InitializeComponent();
//...
YesImage = Properties.Resources.YesImage;
NoImage = Properties.Resources.NoImage;
listBox1.DrawMode = DrawMode.OwnerDrawFixed;
listBox1.DrawItem += (s, e) => OnListBoxDrawItem(s, e);
this.FormClosed += (s, e) => { YesImage.Dispose(); NoImage.Dispose(); };
}
private void OnListBoxDrawItem(object sender, DrawItemEventArgs e)
{
if (e.Index == -1) return;
var game = listBox1.Items[e.Index] as Game;
var backColor = e.State.HasFlag(DrawItemState.Selected)
? e.BackColor
: listBox1.BackColor;
var bmp = game.GameAvailable ? YesImage : NoImage;
var rectImage = new Rectangle(
3, e.Bounds.Y + ((e.Bounds.Height - bmp.Height) / 2),
bmp.Width, bmp.Height
);
var rectTxt = new Rectangle(
rectImage.Right + 3, e.Bounds.Y,
e.Bounds.Right - rectImage.Right - 3,
e.Bounds.Height
);
using (var br = new SolidBrush(backColor))
e.Graphics.FillRectangle(br, e.Bounds);
e.Graphics.DrawImage(bmp, rectImage);
TextRenderer.DrawText(e.Graphics, game.GameName, e.Font,
rectTxt, Color.Black, backColor,
TextFormatFlags.Left | TextFormatFlags.VerticalCenter);
}