wtpcolordropdownlist.cs

来自「C#编写的在线用户统计、在线编辑器、验证码图片」· CS 代码 · 共 150 行

/*
 * WtpColorDropDownList.cs @Microsoft Visual Studio 2008 <.NET Framework 2.0 (or Higher)>
 * AfritXia
 * 2008/3/17
 *
 * Copyright(c) http://www.AfritXia.NET/
 *
 */

using System;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Net.AfritXia.Web.UI
{
    /// <summary>
    /// 颜色下拉列表框
    /// </summary>
    internal class WtpColorDropDownList : WtpDropDownList
    {
        // 首选项
        private string m_firstOption = null;

        #region 类构造器
        /// <summary>
        /// 类参数构造器
        /// </summary>
        /// <param name="firstOption">首选项</param>
        public WtpColorDropDownList(string firstOption)
            : base()
        {
            this.m_firstOption = firstOption;
        }
        #endregion

        /// <summary>
        /// 控件初始化函数
        /// </summary>
        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);

            // 添加首选项
            if (this.m_firstOption != null && this.m_firstOption != "")
                this.Items.Add(new ListItem(this.m_firstOption));

            // 加入颜色值
            foreach (object value in Enum.GetValues(typeof(MyColor)))
            {
                // 转型为枚举值
                MyColor enumValue = (MyColor)value;
                // 获取字符串值
                string valueString = value.ToString();

                // 建立选项 <option></option>
                ListItem option = new ListItem();

                // 设置选项值
                option.Value = valueString;
                // 设置选项文本
                option.Text = valueString;

                // 添加 CSS 样式表
                option.Attributes.CssStyle.Add("background-color", valueString);

                // 如果背景色过深，则需要反色
                if (IsNeedToInverseColor(enumValue))
                    option.Attributes.CssStyle.Add("color", MyColor.White.ToString());

                this.Items.Add(option);
            }
        }

        /// <summary>
        /// 是否需要反色
        /// </summary>
        /// <param name="enumValue">颜色枚举值</param>
        /// <returns></returns>
        private bool IsNeedToInverseColor(MyColor enumValue)
        {
            if (enumValue == MyColor.Black || enumValue == MyColor.Blue)
                return true;

            if (enumValue == MyColor.Gray || enumValue == MyColor.Green)
                return true;

            if (enumValue == MyColor.Maroon)
                return true;

            if (enumValue == MyColor.Navy)
                return true;

            if (enumValue == MyColor.Olive)
                return true;

            if (enumValue == MyColor.Purple)
                return true;

            if (enumValue == MyColor.Teal)
                return true;

            return false;
        }

        #region MyColor 自定义颜色枚举
        /// <summary>
        /// MyColor 自定义颜色枚举
        /// </summary>
        private enum MyColor
        {
            // Aqua = 0x00ffff
            Aqua,
            // Black = 0x000000
            Black,
            // Blue = 0x0000ff
            Blue,
            // Fuchsia = 0xff00ff
            Fuchsia,
            // Gray = 0x808080
            Gray,
            // Green = 0x008000
            Green,
            // Lime = 0x00ff00
            Lime,
            // LightGray = 0xd3d3d3
            LightGrey,
            // Maroon = 0x800000
            Maroon,
            // Navy = 0x000080
            Navy,
            // Olive = 0x808000
            Olive,
            // Pink = 0xffc0cb
            Pink,
            // Purple = 0x800080
            Purple,
            // Red = 0xff0000
            Red,
            // Silver = 0xc0c0c0
            Silver,
            // Teal = 0x008080
            Teal,
            // White = 0xffffff
            White,
            // Yellow = 0xffff00
            Yellow
        };
        #endregion
    }
}