C#多选下拉菜单自定义控件

C#在winform项目中 多选下拉菜单自定义控件 。

由 ComboBox 和 CheckedListBox 组合形成。

效果：

自定义控件代码

MultiComboBox.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace HL_MultiComboBox
{
    public partial class MultiComboBox : UserControl
    {

        public ComboBox ComboBox = new ComboBox();
        public CheckedListBox CheckedListBox { get; set; }  //为选项赋值的接口
        public List<string> SelectedItems1 { get; set; }  //传递已选择项目的接口
 
        public MultiComboBox()
        {
            InitializeComponent();

            this.VerticalScroll.Enabled = true;
            this.AutoSize = true;
            CheckedListBox=new CheckedListBox();
            CheckedListBox.CheckOnClick = true;
            CheckedListBox.Visible = false;
            ComboBox = new ComboBox();
            ComboBox.Width = 150;
            ComboBox.DrawMode = DrawMode.OwnerDrawFixed;
            ComboBox.IntegralHeight = false;
            ComboBox.DroppedDown = false;
            ComboBox.DropDownHeight = 1;
            ComboBox.DropDownStyle = ComboBoxStyle.DropDown;
            ComboBox.AutoCompleteSource = AutoCompleteSource.ListItems;
            CheckedListBox.MouseUp += MouseUp1;
            CheckedListBox.MouseLeave += MouseLeave1;
            ComboBox.MouseDown += MouseDown1;
            ComboBox.DropDown += MouseLeave2;
            this.Controls.Add(ComboBox);   //添加控件
        }

        //
        #region 订阅方法模块
        //
        private void MouseLeave1(object sender, EventArgs e)  //鼠标离开CheckedListBox，隐藏CheckedListBox
        {
            CheckedListBox.Hide();
        }
        private void MouseLeave2(object sender, EventArgs e)  //ComboBox下拉时，显示下拉框
        {
            // 显示下拉框
            CheckedListBox.Width = ComboBox.Width;
            CheckedListBox.Size = new Size(ComboBox.DropDownWidth, CheckedListBox.Items.Count * 18);
            CheckedListBox.Location = new Point(ComboBox.Left, ComboBox.Height);
            Controls.Add(CheckedListBox);
            CheckedListBox.Visible = true;
        }
        private void MouseUp1(object sender, EventArgs e)  //在CheckedListBox中选择后，在ComboBox中显示相应项目
        {
            var list = new List<string>();
            foreach (var v in CheckedListBox.CheckedItems)  //将选择的项目加入list
            {
                list.Add(v.ToString());
            }
            ComboBox.Text = String.Join(",", list);
            SelectedItems1 = list;  //把选项赋给传递接口
        }
        private void MouseDown1(object sender, EventArgs e) //在ComboBox的下拉三角按下鼠标时，不显示ComboBox的下拉框，显示CheckedListBox当作其下拉框
        {
            ComboBox.DroppedDown = false;
        }
        #endregion 
 

    }
}

MultiComboBox.Designer.cs

       #region 组件设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.SuspendLayout();
            // 
            // MultiComboBox
            // 
            this.Name = "MultiComboBox";
            this.Size = new System.Drawing.Size(278, 50);
            this.ResumeLayout(false);

        }

        #endregion

使用方法

拖 multComboBox 控件至窗体中 名为 multiComboBox1

       private void Form1_Load(object sender, EventArgs e)
        {
            this.multiComboBox1.ComboBox.Width = 300;
            //为下拉菜单添加选项
            this.multiComboBox1.CheckedListBox.Items.Add("1");
            this.multiComboBox1.CheckedListBox.Items.Add("2");
            this.multiComboBox1.CheckedListBox.Items.Add("3");
            this.multiComboBox1.CheckedListBox.Items.Add("4");
            this.multiComboBox1.CheckedListBox.Items.Add("5");
            this.multiComboBox1.CheckedListBox.Items.Add("6");
            this.multiComboBox1.CheckedListBox.Items.Add("7");
            this.multiComboBox1.CheckedListBox.Items.Add("8");
            this.multiComboBox1.CheckedListBox.Items.Add("9");
            this.multiComboBox1.CheckedListBox.Items.Add("10");

 
        }

        private void button1_Click(object sender, EventArgs e)
        {
            var strSelected = multiComboBox1.SelectedItems1;
            string strResult = string.Join(",", strSelected);
            MessageBox.Show(strResult);

        }