Question

我有一个listBox的UserControl：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Lightnings_Extractor
{
    public partial class ListBoxControl : UserControl
    {

        private List<int> m_itemIndexes = new List<int>();

        public ListBoxControl()
        {
            InitializeComponent();

            this.listBox1.SelectedIndex = 0;
        }

        private void listBox1_MouseDown(object sender, MouseEventArgs e)
        {
            int index = listBox1.IndexFromPoint(e.X, e.Y);
            listBox1.SelectedIndex = index;

            if (e.Button == System.Windows.Forms.MouseButtons.Right)
            {
                if (m_itemIndexes.Contains(index))
                    return;

                m_itemIndexes.Add(index);
                DrawItem(index);
            }
            else if (e.Button == MouseButtons.Left)
            {
                if (!m_itemIndexes.Contains(index))
                    return;

                m_itemIndexes.Remove(index);
                DrawItem(index);
            }
        }

        private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
        {
            bool coloring = m_itemIndexes.Contains(e.Index);
            bool selected = (e.State & DrawItemState.Selected) == DrawItemState.Selected;

            if (coloring)
            {
                using (var brush = new SolidBrush(Color.Red))
                {
                    e.Graphics.FillRectangle(brush, e.Bounds);
                }
            }
            else
            {
                e.DrawBackground();
            }

            string item = listBox1.Items[e.Index].ToString();
            e.Graphics.DrawString(item, e.Font, selected || coloring ? Brushes.White : Brushes.Black, e.Bounds, StringFormat.GenericDefault);

            if (selected)
                e.DrawFocusRectangle();
        }

        private void DrawItem(int index)
        {
            Rectangle rectItem = listBox1.GetItemRectangle(index);
            listBox1.Invalidate(rectItem);
        }
    }
}

例如这一行：

using (var brush = new SolidBrush(Color.Red))

现在它设置为红色。但我希望用户能够在他的代码或其他形式或类别的任何地方将其更改为任何颜色。而且不仅仅是在这个UserControl代码中。

我如何添加这样的属性？

Answer 1

只需按照惯例声明属性：

[Browsable(true)] //so it appears in object explorer
public Color MyListColor
{
  get { return m_MyListColor;}
  set 
  {
    m_MyListColor = value;
    Refresh();//or Update
  }
}

将属性设置为新值后，它会调用Refresh（）重新绘制包括画笔在内的控件。

Answer 2

只需添加一个新属性。

public Brush Fill {get;set;}

如何向UserControl添加一些属性？

2 个答案: