ArcEngine+C# ——下拉框（ComboBox）颜色控件 （转）

转自：http://blog.youkuaiyun.com/lanpy88/article/details/5856295

这一篇介绍如何写一个单色和渐变色的颜色选择下拉框（ComboBox）控件。有些功能中，需要用户自定义选颜色时，一般只需调用ColorDialog颜色选择控件就可以了，但如果为了更贴近ArcGIS的操作风格，且需要使用渐变颜色时，ColorDialog可能就不能满足需求了。

熟悉ArcGIS操作的朋友可能记得，在图层、要素等的颜色设置时用到颜色下拉框选择颜色，其中就有选渐变颜色的下拉框，如下图。在某些二次开发项目中可能会遇到类似的颜色选择需求，希望这里的介绍对需要的朋友能起到一点帮助作用。

 

TIN模型按高程选择渐变颜色

 

1.单色颜色下拉框

其思路就是往ComboBox中添加记录颜色值的项（Item），再根据该颜色值重绘ComboBox对应项的矩形区域，达到直接显示的效果。

具体步骤如下：

先在项目下添加一个新的UserControl控件，再拖一个ComboBox控件到UserControl上，将ComboBox的Dock属性设为Fill，再调整UserControl的大小，使其与刚好完全位于ComboBox下，最后关键的一步就是加入代码。下面贴上代码，具体的解释见代码注释，效果如下图：

单一色效果

using System.Windows.Forms;

using System.Drawing;

using System;

namespace WindowsFormsApplication1

{

    /// <summary>

    /// 单一颜色选择控件类

    /// </summary>

    public partial class PureColorComboBox : UserControl

    {

        private Color _SelectedColor;

 

        /// <summary>

        /// 已选择颜色，封装字段

        /// </summary>

        public Color SelectedColor

        {

            get { return _SelectedColor; }

            set { _SelectedColor = value; }

        }

 

        /// <summary>

        /// Combobox颜色选择发生变化时激发的事件

        /// </summary>

        public event EventHandler SelectColorChanged;

 

        //自定义的初始颜色值，有必要时可以指定一些特定的颜色

        //private static string[] colorList =

        //{

        //    "AliceBlue","AntiqueWhite","Aqua","Aquamarine","Azure","Beige",

        //    "Bisque","Black","BlanchedAlmond","Blue","BlueViolet","Brown",

        //    "BurlyWood","CadetBlue","Chartreuse","Chocolate","Coral",

        //    "CornflowerBlue","Cornsilk","Crimson","Cyan","DarkBlue","DarkCyan",

        //    "DarkGoldenrod","DarkGray","DarkGreen","DarkKhaki","DarkMagenta",

        //    "DarkOliveGreen","DarkOrange","DarkOrchid"

        //};

 

        /// <summary>

        /// 构造函数

        /// </summary>

        public PureColorComboBox()

        {

            InitializeComponent();

            AddComponent();

        }

 

        /// <summary>

        /// 加载各颜色项(Items)

        /// </summary>

        private void AddComponent()

        {

            this.comboBox1.DrawMode = DrawMode.OwnerDrawFixed;

            this.comboBox1.DropDownStyle = ComboBoxStyle.DropDownList;

            //设定ComboBox的高度

            this.comboBox1.ItemHeight = 18;

 

            this.comboBox1.BeginUpdate();

            this.comboBox1.Items.Clear();

 

            //如要使用自定义颜色初始值时则使用这段代码

            //foreach (string oneColor in colorList)

            //{

            //    this.comboBox1.Items.Add(oneColor);

            //}

 

            //加载系统所有的颜色，如果使用自定义颜色初始值时则注销下面的代码

            Array colors = System.Enum.GetValues(typeof(KnownColor));

            for (int i = colors.GetLength(0) - 1; i >= 0; i--)

            {

                this.comboBox1.Items.Add(colors.GetValue(i).ToString());

            }

 

            this.comboBox1.EndUpdate();

        }

 

        //在ComboBox的DrawItem事件（绘制事件）中绘制颜色矩形框，每次添加Item时都会触发该事件

        //该函数由在ComboBox的属性标签的事件栏下双击DrawItem自动生成

        //当然，也可以自己在前面添加

        //this.comboBox1.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.comboBox1_DrawItem);

        private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)

        {

            if (e.Index < 0)

                return;

            Rectangle rect = e.Bounds;  //获取Item矩形框

 

            //获取对应项记录的颜色值

            string colorName = comboBox1.Items[e.Index].ToString();

            //新建单一色刷子，颜色为对应项记录的值

            SolidBrush brush = new SolidBrush(Color.FromName(colorName));

 

            _SelectedColor = brush.Color;

            //为美观，可缩小选定项区域1个像素

            rect.Inflate(-1, -1);

            // 填充颜色

            e.Graphics.FillRectangle(brush, rect);

            // 用黑色绘制颜色边框

            e.Graphics.DrawRectangle(Pens.Black, rect);

        }

 

        /// <summary>

        /// 在ComboBox选择项改变触发事件中激活颜色传递事件

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)

        {

            //如果使用该控件的窗体注册了SelectColorChanged事件，则激活

            //相当于用SelectColorChanged事件替换了ConboBox的SelectedIndexChanged事件

            if (SelectColorChanged != null)

            {

                SelectColorChanged(this, e);

            }

        }

    }

}

最后，将该颜色控件像使用其他控件一样拖入需要的窗体中，在该控件的SelectColorChanged事件下，通过控件的SelectedColor属性获得选择的颜色值：

        //下拉框所选颜色值发生改变时触发的事件

        private void colorComboBox1_SelectColorChanged(object sender, EventArgs e)

        {

            //通过ComboBox的SelectedColor公共字段获取当前选中的值

            MessageBox.Show("当前选中的颜色为： "+this.colorComboBox1.SelectedColor.ToString());

        }

2.渐变色的颜色下拉框

渐变的颜色下拉框的与单色下拉框的思路是一样的，只是着色方案和初始颜色设定稍微不同，这里只把的代码贴出来，注释较略，其他则可参照上传的具体实例，效果如下：

渐变色颜色下拉框

using System.Windows.Forms;

using System.Drawing;

using System;

using System.Drawing.Drawing2D;

namespace WindowsFormsApplication1

{

    public partial class GradientColorComboBox : UserControl

    {

        private Color _FromColor;

        private Color _ToColor;

 

        public Color FromColor

        {

            get { return _FromColor; }

            set { _FromColor = value; }

        }

 

        public Color ToColor

        {

            get { return _ToColor; }

            set { _ToColor = value; }

        }

 

        public event EventHandler SelectColorChanged;

 

        //预定义的渐变色

        private static string[] colorList =

        {

            "AliceBlue|AntiqueWhite","Aqua|Aquamarine","Azure|Beige",

            "Bisque|Black","BlanchedAlmond|Blue","BlueViolet|Brown",

            "BurlyWood|CadetBlue","Chartreuse|Chocolate",

            "CornflowerBlue|Cornsilk","Crimson|Cyan","DarkBlue|DarkCyan",

            "DarkGoldenrod|DarkGray","DarkGreen|DarkKhaki",

            "DarkMagenta|DarkOliveGreen","DarkOrange|DarkOrchid"

        };

 

        public GradientColorComboBox()

        {

            InitializeComponent();

            PersonalizeComponent();

        }

 

        private void PersonalizeComponent()

        {

            this.comboBox1.DrawMode = DrawMode.OwnerDrawFixed;

            this.comboBox1.DropDownStyle = ComboBoxStyle.DropDownList;

            this.comboBox1.ItemHeight = 18;

            this.comboBox1.BeginUpdate();

            this.comboBox1.Items.Clear();

 

            foreach (string oneColor in colorList)

            {

                this.comboBox1.Items.Add(oneColor);

            }

            this.comboBox1.EndUpdate();

        }

 

        private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)

        {

            if (e.Index < 0)

                return;

 

            Rectangle rect = e.Bounds;

            //读取起始、终止颜色值

            string fColorName = comboBox1.Items[e.Index].ToString().Split('|')[0];

            string tColorName = comboBox1.Items[e.Index].ToString().Split('|')[1];

            _FromColor = Color.FromName(fColorName);

            _ToColor = Color.FromName(tColorName);

            //选择线性渐变刷子

            LinearGradientBrush brush = new LinearGradientBrush(rect, _FromColor, _ToColor, 0, false);

 

            rect.Inflate(-1, -1);

            // 填充颜色

            e.Graphics.FillRectangle(brush, rect);

            // 绘制边框

            e.Graphics.DrawRectangle(Pens.Black, rect);

        }

 

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)

        {

            if (SelectColorChanged != null)

            {

                SelectColorChanged(this, e);

            }

        }

    }

}

同样，将该渐变色控件拖入需要使用窗体中，在该控件的SelectColorChanged事件下，通过控件的FromColor和ToColor属性获得选择的渐变色值：

        private void gradientColorComboBox1_SelectColorChanged(object sender, EventArgs e)

        {

            MessageBox.Show("当前选中的颜色为： " + this.gradientColorComboBox1.FromColor.ToString() + this.gradientColorComboBox1.ToColor.ToString());

        }