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

HL_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 HL_MultiComboBox : UserControl
    {
        public ComboBox ComboBox = new ComboBox();
        public CheckedListBox CheckedListBox { get; set; }  //为选项赋值的接口
        public List<string> SelectedItems { get; set; }  //传递已选择项目的接口
        public string Text {
            get { return this.ComboBox.Text; }
            set { this.ComboBox.Text=Text; }
        }
        public HL_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

            //默认样式
            this.ComboBox.Width = 200;
            this.ComboBox.Cursor = System.Windows.Forms.Cursors.Hand;
            this.ComboBox.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
            this.ComboBox.Font = new System.Drawing.Font("微软雅黑", 10.28571F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
            this.ComboBox.FormattingEnabled = true;
            this.ComboBox.Size = new System.Drawing.Size(200, 31);

            this.CheckedListBox.Font = new System.Drawing.Font("宋体", 10.28571F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
            this.CheckedListBox.Cursor = System.Windows.Forms.Cursors.Hand;

        }
        //
        #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 HL_MultiComboBox_Leave(object sender, EventArgs e)
        {
            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-1;
            //if (CheckedListBox.Items.Count > 30)
            //{
            CheckedListBox.Size = new Size(ComboBox.DropDownWidth, 300);//固定 最大显示  高度
            //    //this.CheckedListBox.Height = 300;//下拉菜单 最大显示 高度
            //}
            //else
            //{
            //    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);
            this.SelectedItems = 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 

    }
}

 

HL_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 = "HL_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 = 200;
            //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");
            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");//DataTable 赋值方式
            //string strSqlList = "SELECT value_name FROM item_value where deleted=0 and value_name<>'' and item_name='数据来源' order by orderby+0 asc ";
            //DataTable dtList = clsDBHelperMySQL.m_Query(strSqlList);//执行sql
            //foreach (DataRow row in dtList.Rows)
            //{
            //    this.multiComboBox1.CheckedListBox.Items.Add(row[0]);
            //}
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string strResult = "";
            //取值方式
            //一、 seleced方式
            //if (this.multiComboBox1.SelectedItems != null)
            //{
            //    var strSelected = multiComboBox1.SelectedItems;
            //    strResult = string.Join(",", strSelected);
            //}

            //二、 ComboBox.Text方式
            strResult = this.multiComboBox1.Text;
            MessageBox.Show(strResult);

            //生成 SQL 语句 用 In 方式
            //if (strContactSource != "")
            //{
            //    if (strContactSource.Contains(",") == false)// 在文字两侧加上单引号
            //    {
            //        strContactSource = "'" + strContactSource + "'";
            //    }
            //    else
            //    {
            //        strContactSource = strContactSource.Replace(",", "','");
            //        strContactSource = "'" + strContactSource + "'";
            //    }
            //    strWhere = strWhere + " and ( contact_source in ( " + strContactSource + " )  ) ";
            //}

        }