自定义CheckListBox荣誉2列

Question

我创建了一个自定义检查列表框，这样我就可以更改某些项目的前景色，但是当我启用 MutiColumn 为真时，值相互重叠而不是在多个列中工作。

public sealed class CustomCheckedListBox : CheckedListBox
{
    public CustomCheckedListBox()
    {
        DoubleBuffered = true;
    }

    protected override void OnDrawItem(DrawItemEventArgs e)
    {
        Size checkSize = CheckBoxRenderer.GetGlyphSize(e.Graphics,
            System.Windows.Forms.VisualStyles.CheckBoxState.MixedNormal);
        int dx = (e.Bounds.Height - checkSize.Width)/2;
        e.DrawBackground();
        bool isChecked = GetItemChecked(e.Index); //For some reason e.State doesn't work so we have to do this instead.
        CheckBoxRenderer.DrawCheckBox(e.Graphics, new Point(dx, e.Bounds.Top + dx),
            isChecked
                ? System.Windows.Forms.VisualStyles.CheckBoxState.CheckedNormal
                : System.Windows.Forms.VisualStyles.CheckBoxState.UncheckedNormal);
        using (StringFormat sf = new StringFormat {LineAlignment = StringAlignment.Center})
        {
            using (Brush brush = new SolidBrush(isChecked ? CheckedItemColor : BackColor))
            {
                e.Graphics.DrawString(Items[e.Index].ToString(), Font, brush,
                    new Rectangle(e.Bounds.Height, e.Bounds.Top, e.Bounds.Width - e.Bounds.Height, e.Bounds.Height), sf);
            }
        }
    }

    private Color _checkedItemColor = Color.Blue;

    public Color CheckedItemColor
    {
        get { return _checkedItemColor; }
        set
        {
            _checkedItemColor = value;
            Invalidate();
        }
    }
}

任何人都可以建议为避免这种情况发生而需要进行的任何更改吗？

Answer 1

您的矩形坐标不准确。此外，控件使用 TextRenderer class 绘制文本：

protected override void OnDrawItem(DrawItemEventArgs e) {
  e.DrawBackground();
  bool isChecked = GetItemChecked(e.Index);
  Size checkSize = CheckBoxRenderer.GetGlyphSize(e.Graphics, CheckBoxState.MixedNormal);

  CheckBoxRenderer.DrawCheckBox(e.Graphics,
    new Point(e.Bounds.Left + 2,
              e.Bounds.Top + (e.Bounds.Height / 2) - (checkSize.Height / 2)),
    isChecked ? CheckBoxState.CheckedNormal : CheckBoxState.UncheckedNormal);

  TextRenderer.DrawText(e.Graphics, Items[e.Index].ToString(), Font,
    new Rectangle(e.Bounds.Left + checkSize.Width + 3, e.Bounds.Top,
                  e.Bounds.Width - (checkSize.Width + 3), e.Bounds.Height - 1),
    isChecked ? CheckedItemColor : ForeColor, Color.Empty, TextFormatFlags.VerticalCenter);
}

自定义CheckListBox荣誉2列

Custom CheckListBox Honor 2 columns

c#

winforms

checklistbox