学步园

最近在做东西的时候，需要做一些具有特殊功能的ComboBox，于是就写了一些控件，本篇主要介绍支持多列数据显示的ComboBox，为需要的朋友提供一些参考，控件下载后，都可以直接使用。

开发环境：Visual Studio.net 2003
控 件 名：MultiColumnComboBox

MultiColumnComboBox.cs
  1using System;
  2using System.Data;
  3using System.Drawing;
  4using System.Windows.Forms;
  5
  6namespace EBright.Controls.Form.MultiColumnComboBox
  7{
  8    /**//// <summary>
  9    /// 支持多列数据显示的ComboBox
 10    /// </summary>
 11    public class MultiColumnComboBox:ComboBox
 12    {
 13        variables#region variables
 14        private System.ComponentModel.Container components = null;
 15        //确定哪些列显示出来
 16        private int[] _displayColumns = null;
 17        //计算显示列的显示宽度
 18        private int[] _displayWidths = null;
 19        //数据表
 20        private DataTable _dtSource = null;
 21        //显示的数据行
 22        private DataRow[] _drDisplay = null;
 23        //列与列之间的间隙
 24        private int _columnSpacing = 4;
 25        //是否是第一次初始化items
 26        private bool _needInitItem = true;
 27        #endregion
 28
 29        initialize#region initialize
 30        public MultiColumnComboBox()
 31        {
 32            if(components == null)
 33                components = null;
 34            this.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable ;
 35        }
 36
 37        Component Designer generated code#region Component Designer generated code
 38        /**//// <summary>
 39        /// Required method for Designer support - do not modify 
 40        /// the contents of this method with the code editor.
 41        /// </summary>
 42        private void InitializeComponent()
 43        {
 44        }
 45
 46        #endregion
 47        #endregion
 48
 49        Inherited events#region Inherited events
 50        protected override void OnDrawItem(DrawItemEventArgs e)
 51        {
 52            try
 53            {
 54                int iIndex = e.Index;
 55                if(_drDisplay == null)
 56                    return;
 57                if(iIndex >= _drDisplay.Length)
 58                    return;
 59                if(iIndex > -1)
 60                {
 61                    int iXPos = 0;
 62                    int iYPos = 0;
 63
 64                    if(_drDisplay.Length == 0)
 65                        return;    
 66                    e.DrawBackground();
 67                    for(int index = 0; index < _dtSource.Columns.Count; index++)
 68                    {
 69                        if(!this.ColumnIsDisplay(index,_displayColumns))
 70                            continue;
 71                        int idwIndex = GetColumnIndexOfArray(_displayColumns,index);
 72                        int idw = idwIndex==-1?80:_displayWidths[idwIndex];
 73                        e.Graphics.DrawString(_drDisplay[iIndex][index].ToString(), Font, new SolidBrush(e.ForeColor), new RectangleF(iXPos, e.Bounds.Y, idw, ItemHeight));
 74                        iXPos += idw + _columnSpacing ;
 75                    }
 76                    iXPos = 0;
 77                    iYPos += ItemHeight;
 78                    e.DrawFocusRectangle();
 79                    base.OnDrawItem(e);
 80                }
 81            }
 82            catch(Exception ex)
 83            {
 84                throw new Exception(ex.Message + "\r\nIn ColumnComboBox.OnDrawItem(DrawItemEventArgs).");
 85            }
 86        }
 87
 88        protected override void OnDropDown(EventArgs e)
 89        {
 90            if(_needInitItem)
 91            {
 92                InitItems();
 93                _needInitItem = false;
 94            }
 95            InitDisplay();
 96            base.OnDropDown (e);
 97        }
 98
 99        protected override void OnDataSourceChanged(EventArgs e)
100        {
101            base.OnDataSourceChanged (e);
102            InitDisplay();
103        }
104        #endregion
105
106        Property#region Property
107        public int[] DisplayColumns
108        {
109            get{return _displayColumns;}
110            set{_displayColumns = value;}
111        }
112        public DataTable Data
113        {
114            get{return _dtSource ;}
115            set
116            {
117                DataSource = value;
118                _dtSource = value;
119            }
120        }
121        #endregion
122
123        private methods#region private methods
124        private bool ColumnIsDisplay(int column,int[] columns)
125        {
126            if(column< 0)
127                throw new Exception("column must be greater than 0.\r\n(private method)ColumnIsDisplay(int,int[])") ;
128            if(columns == null)
129            {
130                columns = new int[1] ;
131                columns[0] = 0;
132            }
133            else if(_dtSource != null)
134            {
135                if(columns.Length > _dtSource.Columns.Count)
136                    throw new Exception("DisplayColumns' count cannot be greater than count of datasource.\r\n(private method)ColumnIsDisplay(int,int[])") ;
137            }
138            foreach(int c in columns)
139            {
140                if(c == column)
141                    return true;
142            }