Question

我创建了一个格式化条件：

如果文本包含- Success ，则背景颜色为 Green ，ForeGround颜色为 Black < / strong>;

如果文本包含- Error ”彩色背景 Red ，则前景为 Black ;

其他情况：背景颜色为 White ，前景色为 Black ；

问题。
如何更改我选择满足条件1 的ListBox项的背景/前景颜色？

条件1 。所选项目的条件：

背景Color.Blue；

前景Color.White（或Color.Black）；

问题：
我的代码未绘制ListBox项，即Color.White。

private SolidBrush reportsForegroundBrushSelected = new SolidBrush(Color.Black); private SolidBrush reportsBackgroundBrushSelected = new SolidBrush(Color.FromKnownColor(KnownColor.Highlight)); private SolidBrush reportsForegroundBrush = new SolidBrush(Color.Black); private SolidBrush reportsBackgroundBrush1 = new SolidBrush(Color.LimeGreen); private SolidBrush reportsBackgroundBrush2 = new SolidBrush(Color.Salmon); private SolidBrush reportsBackgroundBrush3 = new SolidBrush(Color.White); private void listBox1_DrawItem(object sender, DrawItemEventArgs e) { e.DrawBackground(); bool selected = ((e.State & DrawItemState.Selected) == DrawItemState.Selected); int index = e.Index; if (index >= 0 && index < listBox1.Items.Count) { string text = listBox1.Items[index].ToString(); Graphics g = e.Graphics; //background: SolidBrush backgroundBrush; if (selected) { backgroundBrush = reportsBackgroundBrushSelected; } else { if (text.Contains("Success")) { backgroundBrush = reportsBackgroundBrush1; } else { backgroundBrush = reportsBackgroundBrush2; } } if (!text.Contains("Success") && !text.Contains("Error")) { backgroundBrush = reportsBackgroundBrush3; } g.FillRectangle(backgroundBrush, e.Bounds); //text: SolidBrush foregroundBrush = (selected) ? reportsForegroundBrushSelected : reportsForegroundBrush; g.DrawString(text, e.Font, foregroundBrush, listBox1.GetItemRectangle(index).Location); } e.DrawFocusRectangle(); }

Answer 1

问题按您的if/else顺序。

像这样设置：

if (selected)
{
    backgroundBrush = reportsBackgroundBrushSelected;
}
else
{
    if (text.Contains("Success"))
    {
        backgroundBrush = reportsBackgroundBrush1;
    }
    else if(text.Contains("Error"))
    {
        backgroundBrush = reportsBackgroundBrush2;
    }
    else
    {
        backgroundBrush = reportsBackgroundBrush3;            
    }
}

Answer 2

即使没有明确要求，我还是建议另一种管理画笔的方法，我认为这可以简化ForeColor / BackColor开关并允许更好地自定义ListBox表示形式。

创建一个包含所有画笔选择/预选的类对象，并在需要时公开公共属性以修改这些值。
另外，此类提供了一种返回正确笔刷组合的方法，并根据以下几种条件选择了正确的笔刷：

当前商品的文本内容
其选择状态（Selected/Focused或NotAccelerator/NotFocusedRect）

该类非常简单。
它具有重载的构造函数，该构造函数允许指定默认值或特定的Color属性，以符合ListBox控件的标准外观。

使用默认（空）构造函数时，ForeGround / BackGround颜色的默认组合设置为Color.Black和Color.White：

public ReportsBrushes() : this(Color.White, Color.Black) { }

否则，它接受2个参数来设置特定值：

public ReportsBrushes(Color ItemBackColor, Color ItemForeColor)
{
    this.StandardForeground = new SolidBrush(ItemForeColor);
    this.StandardBackground = new SolidBrush(ItemBackColor);
}

这简化了ListBox.DrawItem方法：

private ReportsBrushes reportsBrushes = new ReportsBrushes();

private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
    ListBox ctl = sender as ListBox;
    e.Graphics.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
    e.DrawFocusRectangle();

    var itemColors = reportsBrushes.GetItemBrushes(ctl.Items[e.Index].ToString(), e.State.HasFlag(DrawItemState.Selected));

    using (StringFormat format = new StringFormat())
    {
        format.LineAlignment = StringAlignment.Center;
        e.Graphics.DrawString(ctl.Items[e.Index].ToString(), ctl.Font, itemColors.ForeColor, e.Bounds, format);
    }
}

private void listBox1_MeasureItem(object sender, MeasureItemEventArgs e)
{
    e.ItemHeight = listBox1.Font.Height + 4;
}

ReportsBrushes 类：

internal class ReportsBrushes
{
    public ReportsBrushes() : this(Color.White, Color.Black) { }
    public ReportsBrushes(Color ItemBackColor, Color ItemForeColor)
    {
        this.StandardForeground = new SolidBrush(ItemForeColor);
        this.StandardBackground = new SolidBrush(ItemBackColor);
    }
    public SolidBrush StandardForeground { get; set; }
    public SolidBrush StandardBackground { get; set; }

    public SolidBrush SelectedForeground { get ; set ; } = 
        new SolidBrush(Color.FromKnownColor(KnownColor.HighlightText));
    public SolidBrush SelectedBackground { get; set; } = 
        new SolidBrush(Color.FromKnownColor(KnownColor.Highlight));
    public SolidBrush SuccessBackground { get; set; } = 
        new SolidBrush(Color.LimeGreen);
    public SolidBrush ErrorBackground { get; set; } = 
        new SolidBrush(Color.OrangeRed);

    public (SolidBrush ForeColor, SolidBrush BackColor) GetItemBrushes(string ItemText, bool ItemSelected)
    {
        if (ItemSelected)
            return (this.SelectedForeground, this.SelectedBackground);
        else
        {
            if (ItemText.Contains("Success"))
                return (this.StandardForeground, this.SuccessBackground);
            if (ItemText.Contains("Error"))
                return (this.StandardForeground, this.ErrorBackground);
            return (this.StandardForeground, this.StandardBackground);
        }
    }
}

如何更改列表框项目的背景和字体颜色？

2 个答案: