可复选的ComboBox控件
2012-08-04 17:18 尘☆缘 阅读(520) 评论(0) 编辑 收藏 举报由于VS自带的控件ComboBox无法提供复选的功能，所以对ComboBox控件进行了重写，继承来自VS的ComboBox类，结合使用CheckListBox来实现复选的功能。
控件截图如下。
完整代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
namespace ComboBoxEdit
{
public partial class ComboBoxEdit : ComboBox
{
public CheckedListBox list = new CheckedListBox();
Dictionary<object, string> SelectItems = new Dictionary<object, string>();
public ComboBoxEdit()
{
InitializeComponent();
}
#region IsMultiSelect
private bool isMultiSelect = false;
[Description("设置是否允许多选")]
public bool IsMultiSelect
{
get {return isMultiSelect; }
set
{
isMultiSelect = value;
if (isMultiSelect)
{
//只有设置这个属性为OwnerDrawFixed才可让重画起作用
this.DrawMode = DrawMode.OwnerDrawFixed;
this.IntegralHeight = false;
this.DoubleBuffered = true;
this.DroppedDown = false;
this.DropDownHeight = 1;
this.DropDownStyle = ComboBoxStyle.DropDown;
list.CheckOnClick = true;
list.ItemCheck += new ItemCheckEventHandler(list_ItemCheck);
list.MouseUp += new MouseEventHandler(list_MouseUp);
list.MouseLeave += new EventHandler(list_MouseLeave);
list.BorderStyle = BorderStyle.Fixed3D;
list.Visible = false;
}
else
{
//只有设置这个属性为Normal才可让重画不起作用
this.DrawMode = DrawMode.Normal;
this.IntegralHeight = true;
this.DoubleBuffered = true;
this.DropDownHeight = 106;
}
}
}
#endregion
#region SelectedValues
private string[] selectedValues=null;
[Description("选择项的Value值(数组)")]
public string [] SelectedValues
{
get {
if (IsMultiSelect)
{
string str = "";
foreach (KeyValuePair<object, string> m in SelectItems)
{
str = str + m.Key.ToString() + ";";
}
string [] array=str.Split(new char[1]{';'},StringSplitOptions.RemoveEmptyEntries);
return array;
}
return selectedValues;
}
set { selectedValues = value; }
}
#endregion
#region ItemCheck事件
//设置CheckBoxList
private void list_ItemCheck(object sender, ItemCheckEventArgs e)
{
if (e.NewValue == CheckState.Checked)
{
if (SelectItems.ContainsKey(list.SelectedValue))
{ throw new Exception("Value具有重复的值！"); }
SelectItems.Add(list.SelectedValue, list.Text);
}
else if (e.NewValue == CheckState.Unchecked)
{
if (SelectItems.ContainsKey(list.SelectedValue))
{ SelectItems.Remove(list.SelectedValue); }
}
else
{
if (e.NewValue == CheckState.Checked)
{
if (SelectItems.ContainsKey(list.Text))
{
throw new Exception("手工添加的值中有重复的数据！");
}
SelectItems.Add(list.Text, list.Text);
}
else if (e.NewValue == CheckState.Unchecked)
{
if (SelectItems.ContainsKey(list.Text))
{
SelectItems.Remove(list.Text);
}
}
}
}
//设置ComboBox文本值
private void list_MouseUp(object sender, MouseEventArgs e)
{
string str = "";
foreach (KeyValuePair<object, string> m in SelectItems)
{
str = str + m.Value + ";";
}
this.Text = str.Trim(';');
}
//鼠标离开事件
private void list_MouseLeave(object sender, EventArgs e)
{
list.Visible = false;
}
#endregion
#region 重写相关事件
//点击鼠标
protected override void OnMouseDown(MouseEventArgs e)
{
if (IsMultiSelect)
{
this.DroppedDown = false;
}
}
//释放鼠标
protected override void OnMouseUp(MouseEventArgs e)
{
if (IsMultiSelect)
{
this.DroppedDown = false;
}
}
//TextChange事件
protected override void OnTextChanged(EventArgs e)
{
if (!list.Visible)
{
list.DataSource = null;
list.Items.Clear();
SelectItems.Clear();
}
}
//下拉列表事件
protected override void OnDropDown(EventArgs e)
{
if (IsMultiSelect)
{
list.Visible = !list.Visible;
if (list.Visible)
{
list.Focus();
list.ItemHeight = this.ItemHeight;
list.BorderStyle = BorderStyle.FixedSingle;
list.Font = this.Font;
list.Size = new Size(this.DropDownWidth, this.ItemHeight * (this.MaxDropDownItems - 1) - (int)this.ItemHeight / 2);
list.Location = new Point(this.Left, this.Top + this.ItemHeight + 6);
list.BeginUpdate();
if (this.DataSource != null)
{
list.DataSource = this.DataSource;
list.DisplayMember = this.DisplayMember;
list.ValueMember = this.ValueMember;
}
list.EndUpdate();
if (!this.Parent.Controls.Contains(list))
{
this.Parent.Controls.Add(list);
list.BringToFront();
}
}
}
}
#endregion
}
}
