C# ComboBox显示图片与多选

ComboBox多选
新建一个类ComboBoxEx.cs编译后在工具箱里会出现自定义控件。
拖放上去即可和普通ComboBox一样使用，按住Ctrl键可以多选。

代码如下：

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
namespace ComboBoxEx
{
 public class ComboBoxEx:ComboBox
 {
  ListBox lst=new ListBox();
  public ComboBoxEx()
  {
   lst.SelectionMode=SelectionMode.MultiExtended;
   this.DrawMode=DrawMode.OwnerDrawFixed;//只有设置这个属性为OwnerDrawFixed才可能让重画起作用
   lst.KeyUp+=new KeyEventHandler(lst_KeyUp);
   lst.MouseUp+=new MouseEventHandler(lst_MouseUp);
   lst.KeyDown+=new KeyEventHandler(lst_KeyDown);
  }
  #region Property
  [Description("选定项的值"),Category("Data")]
  public ListBox.SelectedObjectCollection SelectedItems
  {
   get
   {
    return lst.SelectedItems;
   }
  }
  #endregion
  #region override
  protected override void OnKeyUp(KeyEventArgs e)
  {
   base.OnKeyDown(e);
   bool Pressed=(e.Control && ((e.KeyData & Keys.A)==Keys.A));
   if(Pressed)
   {
    for(int i=0;i<lst.Items.Count;i++)
     lst.SetSelected(i,true);
   }
  }
  protected override void OnMouseDown(MouseEventArgs e)
  {
   this.DroppedDown=false;
   
  }
  protected override void OnMouseUp(MouseEventArgs e)
  {
   this.DroppedDown=false;
   lst.Focus();
  }
  protected override void OnDropDown(EventArgs e)
  {
   lst.Items.Clear();
   lst.Show();
   lst.ItemHeight=this.ItemHeight;
   lst.BorderStyle=BorderStyle.FixedSingle;
   lst.Size=new Size(this.DropDownWidth,this.ItemHeight*(this.MaxDropDownItems-1)-(int)this.ItemHeight/2);
   lst.Location=new Point(this.Left,this.Top+this.ItemHeight+6);
   lst.BeginUpdate();
   for(int i=0;i<this.Items.Count;i++)   
    lst.Items.Add(this.Items[i]);
   lst.EndUpdate();
   
   this.Parent.Controls.Add(lst);
  }
  #endregion
  private void lst_KeyUp(object sender, KeyEventArgs e)
  {
   this.OnKeyUp(e);
  }
  private void lst_MouseUp(object sender, MouseEventArgs e)
  {
   try
   {
    this.Text="";
    for(int i=0;i<lst.SelectedItems.Count;i++)
    {
     if(i==0)
      this.Text=lst.SelectedItems[i].ToString();
     else  
     {
      this.Text=this.Text+","+lst.SelectedItems[i].ToString();
     }
    }
   }
   catch
   {
    this.Text="";
   }
   bool isControlPressed=(Control.ModifierKeys==Keys.Control);
   bool isShiftPressed=(Control.ModifierKeys==Keys.Shift);
   if(isControlPressed || isShiftPressed)
    lst.Show();
   else
    lst.Hide();
  }
  private void lst_KeyDown(object sender, KeyEventArgs e)
  {
   switch(e.KeyData)
   {
    case Keys.Down:
     if(lst.SelectedItems.Count!=0)
     {
      this.Text=lst.SelectedItem.ToString();
     }
     else
      this.Text=this.Items[0].ToString();
     break;
    case Keys.Up:
     if(lst.SelectedItems.Count!=0)
     {
      this.Text=lst.SelectedItem.ToString();
     }
     else
      this.Text=this.Items[0].ToString();
     break;
   }
  }
 }
}

在ComboBox下拉列表显示图片

定义

  private System.Windows.Forms.ComboBox comboBox1;
  private System.Windows.Forms.ImageList imageList1;

comboBox1下面两个属性一定要设为下面的值。

DrawMode：OwnerDrawFixed； 
DropDownStyle：DropDownList；

imageList1中一定要包函与所添加的项相同数目的图

关键方法，此方法为comboBox1的DrawItem事件所引起的方法。

private void comboBox1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
  {
   Graphics g = e.Graphics ; 
   Rectangle r = e.Bounds ; 
   Size imageSize = imageList1.ImageSize; 
   Font fn = null ; 
   if ( e.Index >= 0 ) 
   { 
    fn = (Font)fontArray[0]; 
    string s = (string)comboBox1.Items[e.Index]; 
    StringFormat sf = new StringFormat(); 
    sf.Alignment = StringAlignment.Near; 
    if ( e.State == ( DrawItemState.NoAccelerator | DrawItemState.NoFocusRect)) 
    { 
     //画条目背景 
     e.Graphics.FillRectangle(new SolidBrush(Color.Red) , r); 
     //绘制图像 
     imageList1.Draw(e.Graphics, r.Left, r.Top,e.Index); 
     //显示字符串 
     e.Graphics.DrawString( s , fn , new SolidBrush(Color.Black), r.Left+imageSize.Width ,r.Top); 
     //显示取得焦点时的虚线框 
     e.DrawFocusRectangle(); 
    } 
    else 
    { 
     e.Graphics.FillRectangle(new SolidBrush(Color.LightBlue) , r); 
     imageList1.Draw(e.Graphics, r.Left, r.Top,e.Index); 
     e.Graphics.DrawString( s , fn , new SolidBrush(Color.Black),r.Left+imageSize.Width ,r.Top); 
     e.DrawFocusRectangle(); 
    } 
   }

  }

 

向combobox中添加数据

comboBox1.Items.Add("小车"); 
   comboBox1.Items.Add("视频"); 
   comboBox1.Items.Add("信号灯"); 

url:http://greatverve.cnblogs.com/archive/2011/07/19/ComboBox-Multi-Pic.html