1、创建多选下拉框控件
csharp
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace DFT_FFTApp.userCtrl
{
/// <summary>
/// 多选下拉控件
/// </summary>
public class MultiComboBox:UserControl
{
public ComboBox ComboBox { get; set; }
public CheckedListBox CheckedListBox { get; set; }
public ComboBox.ObjectCollection Items
{
get
{
return ComboBox?.Items;
}
}
public MultiComboBox()
{
//面板
this.VerticalScroll.Enabled = true;
this.AutoSize = true;
//多项列表
CheckedListBox = new CheckedListBox();
CheckedListBox.CheckOnClick = true;
CheckedListBox.BorderStyle = BorderStyle.Fixed3D;
CheckedListBox.Visible = false;
CheckedListBox.Margin=new Padding(0);
CheckedListBox.MouseUp += (ss, se) =>
{
//更新ComboBox显示文本
var list = new List<string>();
foreach(var item in CheckedListBox.CheckedItems)
{
list.Add(item.ToString());
}
ComboBox.Text = string.Join(",", list);
ComboBox.Tag = list;
};
CheckedListBox.MouseLeave += (ss, se) =>
{
//隐藏多选框
CheckedListBox.Hide();
};
//下拉框
ComboBox=new ComboBox();
ComboBox.Width = 150;
ComboBox.DrawMode = DrawMode.OwnerDrawFixed;
ComboBox.IntegralHeight = false;
ComboBox.DroppedDown = false;
ComboBox.DropDownHeight = 1;
ComboBox.Margin=new Padding(0);
ComboBox.Location=new System.Drawing.Point(0,0);
ComboBox.DropDownStyle = ComboBoxStyle.DropDown;
ComboBox.AutoCompleteSource = AutoCompleteSource.ListItems;
ComboBox.MouseDown += (ss, se) =>
{
ComboBox.DroppedDown = false;
};
ComboBox.MouseLeave += (ss, se) =>
{
//不在下拉区时隐藏多项列表
var curMousePos = this.PointToClient(Control.MousePosition);
var downArea = CheckedListBox.Location;
if (curMousePos.X < downArea.X || curMousePos.X>(downArea.X+CheckedListBox.Width)
|| curMousePos.Y<downArea.Y || curMousePos.Y>(downArea.Y+CheckedListBox.Height))
{
CheckedListBox.Hide();
}
};
ComboBox.DropDown += (ss, se) =>
{
//显示下拉多选框
CheckedListBox.Items.Clear();
//添加并设置选中项
var lastChecked = ComboBox.Tag as List<string>;
ComboBox.BeginUpdate();
foreach(var item in this.Items)
{
var ck = false;
if(lastChecked!=null && lastChecked.Contains(item.ToString()))
{
ck = true;
}
CheckedListBox.Items.Add(item, ck);
}
//显示下拉框
CheckedListBox.Width=ComboBox.Width;
CheckedListBox.ItemHeight = ComboBox.ItemHeight;
CheckedListBox.Size=new Size(ComboBox.DropDownWidth,this.Items.Count*18);
CheckedListBox.Location = new Point(ComboBox.Left, ComboBox.Height);
this.Controls.Add( CheckedListBox );
CheckedListBox.Visible = true;
ComboBox.EndUpdate();
};
//添加控件
this.Controls.Add(ComboBox);
}
}
}
2、程序调用
csharp
using DFT_FFTApp.userCtrl;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace DFT_FFTApp
{
public partial class MainForm : Form
{
MultiComboBox multiComboBox;
public MainForm()
{
InitializeComponent();
multiComboBox = new MultiComboBox();
multiComboBox.Items.AddRange(new string[] { "AIN1", "AIN2", "AIN3", "AIN4" });
multiComboBox.Location = new Point(175, 15);
this.Controls.Add(multiComboBox);
}
private void Btn_ComboBoxTest_Click(object sender, EventArgs e)
{
//显示选择项
CheckedListBox CheckedListBox =multiComboBox.CheckedListBox;
foreach(var item in CheckedListBox.CheckedItems)
{
Console.WriteLine(item);
}
//显示选项列表
//foreach (string item in multiComboBox.Items)
//{
// Console.WriteLine(item);
//}
}
}
}
3、运行结果