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.net WinForm用户控件开发--(3)可多选的下拉列表框

程序员文章站 2022-08-21 17:10:56
     这一节给大家演示一个具有多选功能的下拉列表框,其实就是一个文本框和checkboxlist组合实现的用户控件,换个角度来实现自定义...

     这一节给大家演示一个具有多选功能的下拉列表框,其实就是一个文本框和checkboxlist组合实现的用户控件,换个角度来实现自定义控件。
先来看下效果图吧,我会分几个步骤来具体讲解这个文本框的实现。

                        .net WinForm用户控件开发--(3)可多选的下拉列表框               

    1.界面实现

     我们先来看下界面效果怎样实现,然后再讲解具体的功能性实现。

      先创建一个用户控件,当然是继承UserControl类,这个界面需要用到以下控件来实现

     下拉按钮:是一个button控件

     文本框:显示选中的内容,

     多选列表框: checkboxlist

     全选/取消:是两个LABEL控件

      右下角的黑三角:是一个LABEL控件,可实现拉长下拉列表框.

      窗体:点击下拉按钮,实际是弹出一个窗体,下拉列表框中的控件都在这个窗体中显示

    首先看下下拉按钮的实现

   

[csharp]
/// <summary>  
    /// 重写BUTTON  
    /// </summary>  
    public class ButtonS : Button 
    { 
        public ButtonS() 
        { 
            //防止重绘控件出现闪烁  
            this.SetStyle(ControlStyles.UserPaint, true); 
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true); 
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true); 
        } 
        ButtonState state; 
        //当按钮被按下  
        protected override void OnMouseDown(MouseEventArgs mevent) 
        { 
            state = ButtonState.Pushed; 
            base.OnMouseDown(mevent); 
        } 
 
        //当按钮被释放  
        protected override void OnMouseUp(MouseEventArgs mevent) 
        { 
            state = ButtonState.Normal; 
            base.OnMouseUp(mevent); 
        } 
 
        protected override void OnPaint(PaintEventArgs pevent) 
        { 
            base.OnPaint(pevent); 
            System.Windows.Forms.ControlPaint.DrawComboButton(pevent.Graphics, 0, 0, this.Width, this.Height, state); 
        } 
    } 

/// <summary>
    /// 重写BUTTON
    /// </summary>
    public class ButtonS : Button
    {
        public ButtonS()
        {
            //防止重绘控件出现闪烁
            this.SetStyle(ControlStyles.UserPaint, true);
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
        }
        ButtonState state;
        //当按钮被按下
        protected override void OnMouseDown(MouseEventArgs mevent)
        {
            state = ButtonState.Pushed;
            base.OnMouseDown(mevent);
        }

        //当按钮被释放
        protected override void OnMouseUp(MouseEventArgs mevent)
        {
            state = ButtonState.Normal;
            base.OnMouseUp(mevent);
        }

        protected override void OnPaint(PaintEventArgs pevent)
        {
            base.OnPaint(pevent);
            System.Windows.Forms.ControlPaint.DrawComboButton(pevent.Graphics, 0, 0, this.Width, this.Height, state);
        }
    }
   接下来再看下具有拉动功能的LABEL

  

[csharp]
/// <summary>  
    /// 重写LABEL  
    /// </summary>  
    public class LabelS : Label 
    { 
        public LabelS() 
        { 
            //控件绘制的时候减少闪烁  
            this.SetStyle(ControlStyles.UserPaint, true); 
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true); 
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true); 
        } 
 
        protected override void OnPaint(PaintEventArgs e) 
        { 
            base.OnPaint(e); 
            System.Windows.Forms.ControlPaint.DrawSizeGrip(e.Graphics, Color.Black, 1, 0, this.Size.Width, this.Size.Height); 
        } 
    } 

/// <summary>
    /// 重写LABEL
    /// </summary>
    public class LabelS : Label
    {
        public LabelS()
        {
            //控件绘制的时候减少闪烁
            this.SetStyle(ControlStyles.UserPaint, true);
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            System.Windows.Forms.ControlPaint.DrawSizeGrip(e.Graphics, Color.Black, 1, 0, this.Size.Width, this.Size.Height);
        }
    }
 接下来,我们动态用代码生成这些控件,并设置控件的布局,

 现在构造函数里生成这些控件,然后在用户控件的ComCheckBoxList_Layout事件里面布局这些控件,代码如下

  

[csharp]
/// <summary>  
   /// 带下拉框的用户控件  
   /// </summary>  
   public partial class ComCheckBoxList : UserControl 
   { 
       private TextBox tbSelectedValue; 
       private ButtonS btnSelect;//下拉箭头  
       private LabelS lbGrip;//此LABEL用于设置可以拖动下拉窗体变化  
 
       private CheckedListBox checkListBox; 
       private Label lbSelectAll;//全选  
       private Label lbSelectNo;//取消  
 
       private Form frmCheckList; 
 
       private Panel pnlBack; 
       private Panel pnlCheck; 
 
       private System.Drawing.Point DragOffset; //用于记录窗体大小变化的位置  
       public ComCheckBoxList() 
       { 
           InitializeComponent(); 
           this.Name = "comBoxCheckBoxList"; 
           this.Layout+=new LayoutEventHandler(ComCheckBoxList_Layout); 
 
           //生成控件  
           tbSelectedValue = new TextBox(); 
           tbSelectedValue.ReadOnly = true; 
           tbSelectedValue.BorderStyle = BorderStyle.None; 
 
           //下拉箭头  
           this.btnSelect = new ButtonS(); 
           btnSelect.FlatStyle = FlatStyle.Flat; 
           btnSelect.Click+=new EventHandler(btnSelect_Click); 
 
           //全选  
           this.lbSelectAll = new Label(); 
           lbSelectAll.BackColor = Color.Transparent; 
           lbSelectAll.Text = "全选"; 
           lbSelectAll.Size = new Size(40, 20); 
           lbSelectAll.ForeColor = Color.Blue; 
           lbSelectAll.Cursor = Cursors.Hand ; 
           lbSelectAll.TextAlign = ContentAlignment.MiddleCenter; 
           lbSelectAll.Click+=new EventHandler(lbSelectAll_Click); 
 
           //取消  
           lbSelectNo = new Label(); 
           lbSelectNo.BackColor = Color.Transparent; 
           lbSelectNo.Text = "取消"; 
           lbSelectNo.Size = new Size(40, 20); 
           lbSelectNo.ForeColor = Color.Blue; 
           lbSelectNo.Cursor = Cursors.Hand; 
           lbSelectNo.TextAlign = ContentAlignment.MiddleCenter; 
           lbSelectNo.Click+=new EventHandler(lbSelectNo_Click); 
 
           //生成checkboxlist  
           this.checkListBox = new CheckedListBox(); 
           checkListBox.BorderStyle = BorderStyle.None; 
           checkListBox.Location = new Point(0,0); 
           checkListBox.CheckOnClick = true; 
           checkListBox.ScrollAlwaysVisible = true; 
           checkListBox.LostFocus +=new EventHandler(checkListBox_LostFocus); 
           checkListBox.ItemCheck+=new ItemCheckEventHandler(checkListBox_ItemCheck); 
 
           //窗体  
           frmCheckList = new Form(); 
           frmCheckList.FormBorderStyle = FormBorderStyle.None; 
           frmCheckList.StartPosition = FormStartPosition.Manual; 
           frmCheckList.BackColor = SystemColors.Control; 
           frmCheckList.ShowInTaskbar = false; 
 
           //可拖动窗体大小变化的LABEL  
           lbGrip = new LabelS(); 
           lbGrip.Size = new Size(9,18); 
           lbGrip.BackColor = Color.Transparent; 
           lbGrip.Cursor = Cursors.SizeNWSE; 
           lbGrip.MouseDown+=new MouseEventHandler(lbGrip_MouseDown); 
           lbGrip.MouseMove+=new MouseEventHandler(lbGrip_MouseMove); 
 
           //panel  
           pnlBack = new Panel(); 
           pnlBack.BorderStyle = BorderStyle.Fixed3D; 
           pnlBack.BackColor = Color.White; 
           pnlBack.AutoScroll = false; 
 
           //  
           pnlCheck = new Panel(); 
           pnlCheck.BorderStyle = BorderStyle.FixedSingle; 
           pnlCheck.BackColor = Color.White; ; 
 
           SetStyle(ControlStyles.OptimizedDoubleBuffer, true); 
           SetStyle(ControlStyles.ResizeRedraw, true); 
 
           pnlBack.Controls.Add(tbSelectedValue); 
           pnlBack.Controls.Add(btnSelect); 
 
           this.Controls.Add(pnlBack); 
 
           pnlCheck.Controls.Add(checkListBox); 
           pnlCheck.Controls.Add(lbSelectAll); 
           pnlCheck.Controls.Add(lbSelectNo); 
           pnlCheck.Controls.Add(lbGrip); 
           this.frmCheckList.Controls.Add(pnlCheck); 
 
          
       } 
 
       private void ReloationGrip() 
       { 
 
           lbGrip.Top = this.frmCheckList.Height - lbGrip.Height - 1; 
           lbGrip.Left = this.frmCheckList.Width - lbGrip.Width - 1; 
 
           lbSelectAll.Left =5; 
           lbSelectAll.Top = frmCheckList.Height - lbSelectAll.Height; 
 
           lbSelectNo.Left = 50; 
           lbSelectNo.Top = frmCheckList.Height - lbSelectNo.Height; 
      
 
       } 
 
       #region 事件  
        
      
       //布局  
       private void ComCheckBoxList_Layout(object sender,LayoutEventArgs e) 
       { 
           this.Height = tbSelectedValue.Height + 6; 
           this.pnlBack.Size = new Size(this.Width, this.Height - 2); 
 
           //设置按钮的位置  
           this.btnSelect.Size = new Size(16, this.Height - 6); 
           btnSelect.Location = new Point(this.Width - this.btnSelect.Width - 4, 0); 
 
           this.tbSelectedValue.Location = new Point(2, 2); 
           this.tbSelectedValue.Width = this.Width - btnSelect.Width - 4; 
 
           checkListBox.Height =150; 
 
           //设置窗体  
           this.frmCheckList.Size = new Size(this.Width,this.checkListBox.Height); 
           this.pnlCheck.Size =frmCheckList.Size; 
           
 
           this.checkListBox.Width = this.frmCheckList.Width; 
           this.checkListBox.Height = this.frmCheckList.Height-lbSelectNo.Height; 
 
           ReloationGrip(); 
 
 
       } 
       /// <summary>  
       /// 单价下拉框  
       /// </summary>  
       /// <param name="sender"></param>  
       /// <param name="e"></param>  
       public void btnSelect_Click(object sender,EventArgs e) 
       { 
           if (this.frmCheckList.Visible == false) 
           { 
               Rectangle rec = this.RectangleToScreen(this.ClientRectangle); 
               this.frmCheckList.Location = new Point(rec.X, rec.Y + this.pnlBack.Height); 
               this.frmCheckList.Show(); 
               this.frmCheckList.BringToFront(); 
 
               ReloationGrip(); 
           } 
           else 
               this.frmCheckList.Hide(); 
       } 
 
       //全选事件  
       private void lbSelectAll_Click(object sender, EventArgs e) 
       {  
        
       } 
       //取消  
       private void lbSelectNo_Click(object sender,EventArgs e) 
       {  
        
       } 
 
       private void checkListBox_LostFocus(object sender, EventArgs e) 
       { 
           //如果鼠标位置在下拉框按钮的以为地方,则隐藏下拉框  
           if (!this.btnSelect.RectangleToScreen(this.btnSelect.ClientRectangle).Contains(Cursor.Position)) 
           { 
               frmCheckList.Hide(); 
           } 
       } 
 
       private void checkListBox_ItemCheck(object sender, ItemCheckEventArgs e) 
       { 
 
       } 
 
       /// <summary>  
       /// 鼠标按下  
       /// </summary>  
       /// <param name="sender"></param>  
       /// <param name="e"></param>  
       private void lbGrip_MouseDown(object sender, MouseEventArgs e) 
       { 
           if (e.Button==MouseButtons.Left) 
           { 
               int offsetX = System.Math.Abs(Cursor.Position.X - frmCheckList.RectangleToScreen(this.frmCheckList.ClientRectangle).Right); 
               int offsetY = System.Math.Abs(Cursor.Position.Y - frmCheckList.RectangleToScreen(this.frmCheckList.ClientRectangle).Bottom); 
               this.DragOffset = new Point(offsetX, offsetY); 
           } 
       } 
 
       /// <summary>  
       /// 鼠标移动  
       /// </summary>  
       /// <param name="sender"></param>  
       /// <param name="e"></param>  
       private void lbGrip_MouseMove(object sender,MouseEventArgs e) 
       { 
           if (e.Button==MouseButtons.Left) 
           { 
               //获取拉伸长度  
               int curWidth = Cursor.Position.X - frmCheckList.Location.X; 
               int curHeight = Cursor.Position.Y - frmCheckList.Location.Y; 
                 if (curWidth<this.Width) 
              { 
                    curWidth=this.Width; 
               } 
 
                 if (curHeight<checkListBox.Height) 
              { 
                    curHeight=checkListBox.Height; 
              } 
          
               this.frmCheckList.Size=new Size(this.Width,curHeight); 
               this.pnlCheck.Size=frmCheckList.Size; 
               this.checkListBox.Height=(this.frmCheckList.Height-lbGrip.Height)<50?50:this.frmCheckList.Height-lbGrip.Height; 
 
              ReloationGrip(); 
               SetStyle(ControlStyles.OptimizedDoubleBuffer, true); 
               SetStyle(ControlStyles.ResizeRedraw, true); 
               SetStyle(ControlStyles.UserPaint, true); 
               SetStyle(ControlStyles.AllPaintingInWmPaint, true); 
                
 
 
           } 
       } 
 
       #endregion  
   } 

 /// <summary>
    /// 带下拉框的用户控件
    /// </summary>
    public partial class ComCheckBoxList : UserControl
    {
        private TextBox tbSelectedValue;
        private ButtonS btnSelect;//下拉箭头
        private LabelS lbGrip;//此LABEL用于设置可以拖动下拉窗体变化

        private CheckedListBox checkListBox;
        private Label lbSelectAll;//全选
        private Label lbSelectNo;//取消

        private Form frmCheckList;

        private Panel pnlBack;
        private Panel pnlCheck;

        private System.Drawing.Point DragOffset; //用于记录窗体大小变化的位置
        public ComCheckBoxList()
        {
            InitializeComponent();
            this.Name = "comBoxCheckBoxList";
            this.Layout+=new LayoutEventHandler(ComCheckBoxList_Layout);

            //生成控件
            tbSelectedValue = new TextBox();
            tbSelectedValue.ReadOnly = true;
            tbSelectedValue.BorderStyle = BorderStyle.None;

            //下拉箭头
            this.btnSelect = new ButtonS();
            btnSelect.FlatStyle = FlatStyle.Flat;
            btnSelect.Click+=new EventHandler(btnSelect_Click);

            //全选
            this.lbSelectAll = new Label();
            lbSelectAll.BackColor = Color.Transparent;
            lbSelectAll.Text = "全选";
            lbSelectAll.Size = new Size(40, 20);
            lbSelectAll.ForeColor = Color.Blue;
            lbSelectAll.Cursor = Cursors.Hand ;
            lbSelectAll.TextAlign = ContentAlignment.MiddleCenter;
            lbSelectAll.Click+=new EventHandler(lbSelectAll_Click);

            //取消
            lbSelectNo = new Label();
            lbSelectNo.BackColor = Color.Transparent;
            lbSelectNo.Text = "取消";
            lbSelectNo.Size = new Size(40, 20);
            lbSelectNo.ForeColor = Color.Blue;
            lbSelectNo.Cursor = Cursors.Hand;
            lbSelectNo.TextAlign = ContentAlignment.MiddleCenter;
            lbSelectNo.Click+=new EventHandler(lbSelectNo_Click);

            //生成checkboxlist
            this.checkListBox = new CheckedListBox();
            checkListBox.BorderStyle = BorderStyle.None;
            checkListBox.Location = new Point(0,0);
            checkListBox.CheckOnClick = true;
            checkListBox.ScrollAlwaysVisible = true;
            checkListBox.LostFocus +=new EventHandler(checkListBox_LostFocus);
            checkListBox.ItemCheck+=new ItemCheckEventHandler(checkListBox_ItemCheck);

            //窗体
            frmCheckList = new Form();
            frmCheckList.FormBorderStyle = FormBorderStyle.None;
            frmCheckList.StartPosition = FormStartPosition.Manual;
            frmCheckList.BackColor = SystemColors.Control;
            frmCheckList.ShowInTaskbar = false;

            //可拖动窗体大小变化的LABEL
            lbGrip = new LabelS();
            lbGrip.Size = new Size(9,18);
            lbGrip.BackColor = Color.Transparent;
            lbGrip.Cursor = Cursors.SizeNWSE;
            lbGrip.MouseDown+=new MouseEventHandler(lbGrip_MouseDown);
            lbGrip.MouseMove+=new MouseEventHandler(lbGrip_MouseMove);

            //panel
            pnlBack = new Panel();
            pnlBack.BorderStyle = BorderStyle.Fixed3D;
            pnlBack.BackColor = Color.White;
            pnlBack.AutoScroll = false;

            //
            pnlCheck = new Panel();
            pnlCheck.BorderStyle = BorderStyle.FixedSingle;
            pnlCheck.BackColor = Color.White; ;

            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            SetStyle(ControlStyles.ResizeRedraw, true);

            pnlBack.Controls.Add(tbSelectedValue);
            pnlBack.Controls.Add(btnSelect);

            this.Controls.Add(pnlBack);

            pnlCheck.Controls.Add(checkListBox);
            pnlCheck.Controls.Add(lbSelectAll);
            pnlCheck.Controls.Add(lbSelectNo);
            pnlCheck.Controls.Add(lbGrip);
            this.frmCheckList.Controls.Add(pnlCheck);

         
        }

        private void ReloationGrip()
        {

            lbGrip.Top = this.frmCheckList.Height - lbGrip.Height - 1;
            lbGrip.Left = this.frmCheckList.Width - lbGrip.Width - 1;

            lbSelectAll.Left =5;
            lbSelectAll.Top = frmCheckList.Height - lbSelectAll.Height;

            lbSelectNo.Left = 50;
            lbSelectNo.Top = frmCheckList.Height - lbSelectNo.Height;
     

        }

        #region 事件
       
     
        //布局
        private void ComCheckBoxList_Layout(object sender,LayoutEventArgs e)
        {
            this.Height = tbSelectedValue.Height + 6;
            this.pnlBack.Size = new Size(this.Width, this.Height - 2);

            //设置按钮的位置
            this.btnSelect.Size = new Size(16, this.Height - 6);
            btnSelect.Location = new Point(this.Width - this.btnSelect.Width - 4, 0);

            this.tbSelectedValue.Location = new Point(2, 2);
            this.tbSelectedValue.Width = this.Width - btnSelect.Width - 4;

            checkListBox.Height =150;

            //设置窗体
            this.frmCheckList.Size = new Size(this.Width,this.checkListBox.Height);
            this.pnlCheck.Size =frmCheckList.Size;
          

            this.checkListBox.Width = this.frmCheckList.Width;
            this.checkListBox.Height = this.frmCheckList.Height-lbSelectNo.Height;

            ReloationGrip();


        }
        /// <summary>
        /// 单价下拉框
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        public void btnSelect_Click(object sender,EventArgs e)
        {
            if (this.frmCheckList.Visible == false)
            {
                Rectangle rec = this.RectangleToScreen(this.ClientRectangle);
                this.frmCheckList.Location = new Point(rec.X, rec.Y + this.pnlBack.Height);
                this.frmCheckList.Show();
                this.frmCheckList.BringToFront();

                ReloationGrip();
            }
            else
                this.frmCheckList.Hide();
        }

        //全选事件
        private void lbSelectAll_Click(object sender, EventArgs e)
        {
       
        }
        //取消
        private void lbSelectNo_Click(object sender,EventArgs e)
        {
       
        }

        private void checkListBox_LostFocus(object sender, EventArgs e)
        {
            //如果鼠标位置在下拉框按钮的以为地方,则隐藏下拉框
            if (!this.btnSelect.RectangleToScreen(this.btnSelect.ClientRectangle).Contains(Cursor.Position))
            {
                frmCheckList.Hide();
            }
        }

        private void checkListBox_ItemCheck(object sender, ItemCheckEventArgs e)
        {

        }

        /// <summary>
        /// 鼠标按下
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void lbGrip_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button==MouseButtons.Left)
            {
                int offsetX = System.Math.Abs(Cursor.Position.X - frmCheckList.RectangleToScreen(this.frmCheckList.ClientRectangle).Right);
                int offsetY = System.Math.Abs(Cursor.Position.Y - frmCheckList.RectangleToScreen(this.frmCheckList.ClientRectangle).Bottom);
                this.DragOffset = new Point(offsetX, offsetY);
            }
        }

        /// <summary>
        /// 鼠标移动
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void lbGrip_MouseMove(object sender,MouseEventArgs e)
        {
            if (e.Button==MouseButtons.Left)
            {
                //获取拉伸长度
                int curWidth = Cursor.Position.X - frmCheckList.Location.X;
                int curHeight = Cursor.Position.Y - frmCheckList.Location.Y;
                  if (curWidth<this.Width)
               {
                  curWidth=this.Width;
                }

                  if (curHeight<checkListBox.Height)
               {
                  curHeight=checkListBox.Height;
               }
         
                this.frmCheckList.Size=new Size(this.Width,curHeight);
                this.pnlCheck.Size=frmCheckList.Size;
                this.checkListBox.Height=(this.frmCheckList.Height-lbGrip.Height)<50?50:this.frmCheckList.Height-lbGrip.Height;

               ReloationGrip();
                SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
                SetStyle(ControlStyles.ResizeRedraw, true);
                SetStyle(ControlStyles.UserPaint, true);
                SetStyle(ControlStyles.AllPaintingInWmPaint, true);
               


            }
        }

        #endregion
    }
  这样用户控件的布局以及完成,我们编译项目,就可以拖动用户控件到窗体上,看到效果了

 

2. 绑定和添加数据

        2.1 从数据库中读取数据绑定显示

               既然可以从数据库中读取数据,数据源就可以是DATATABLE,我们在这里为用户控件设置数据源,以及绑定后,要显示的字段,以及对于的值字段。

              为控件添加以下属性

            

[csharp]
/// <summary>  
    /// 设置数据源  
    /// </summary>  
    public object DataSource 
    { 
        set 
        { 
            this.checkListBox.DataSource = value; 
        } 
        get 
        { 
            return checkListBox.DataSource; 
        } 
    } 
    /// <summary>  
    /// 设置值  
    /// </summary>  
    public string ValueMember 
    { 
        set 
        { 
            checkListBox.ValueMember = value; 
        } 
    } 
    /// <summary>  
    /// 设置显示名称  
    /// </summary>  
    public string DisplayMember 
    { 
        set 
        { 
            checkListBox.DisplayMember = value; 
        } 
    } 

    /// <summary>
        /// 设置数据源
        /// </summary>
        public object DataSource
        {
            set
            {
                this.checkListBox.DataSource = value;
            }
            get
            {
                return checkListBox.DataSource;
            }
        }
        /// <summary>
        /// 设置值
        /// </summary>
        public string ValueMember
        {
            set
            {
                checkListBox.ValueMember = value;
            }
        }
        /// <summary>
        /// 设置显示名称
        /// </summary>
        public string DisplayMember
        {
            set
            {
                checkListBox.DisplayMember = value;
            }
        }
          2.2 添加项

           我们也可以不绑定数据源,为控件添加项,所有这里我们要为控件添加一个方法,可以实现手动添加项。

           

[csharp]
/// <summary>  
      /// 添加项  
      /// </summary>  
      public int AddItems(object value) 
      { 
          checkListBox.Items.Add(value); 
          return checkListBox.Items.Count; 
      } 

  /// <summary>
        /// 添加项
        /// </summary>
        public int AddItems(object value)
        {
            checkListBox.Items.Add(value);
            return checkListBox.Items.Count;
        }
    这样我们就为用户控件实现了两种显示数据的方法。下面我们看看在窗体中怎样使用这两种方法

     在窗体上放置两个按钮,然后绑定数据

   

[csharp]
private void button1_Click(object sender, EventArgs e) 
       { 
           //绑定数据源  
           DataTable dt = new DataTable(); 
           DataColumn dc1 = new DataColumn("weibo", typeof(System.String)); 
           dt.Columns.Add(dc1); 
 
           DataColumn dc2 = new DataColumn("mail", typeof(System.String)); 
           dt.Columns.Add(dc2); 
 
           DataColumn dc3 = new DataColumn("blog", typeof(System.String)); 
           dt.Columns.Add(dc3); 
 
 
           for (int i = 0; i < 50; i++) 
           { 
               DataRow dr = dt.NewRow(); 
               dr[0] = "下里巴人simple"; 
               dr[1] = "524300045@qq.com"; 
               dr[2] = "msdn" + i.ToString(); 
               dt.Rows.Add(dr); 
           } 
           comCheckBoxList1.DataSource = dt; 
           comCheckBoxList1.DisplayMember = "weibo"; 
           comCheckBoxList1.ValueMember = "mail"; 
       } 
 
       private void button2_Click(object sender, EventArgs e) 
       { 
           //添加项  
           comCheckBoxList2.AddItems("邮箱:524300045@qq.com"); 
           comCheckBoxList2.AddItems("微博:下里巴人simple"); 
       } 

 private void button1_Click(object sender, EventArgs e)
        {
            //绑定数据源
            DataTable dt = new DataTable();
            DataColumn dc1 = new DataColumn("weibo", typeof(System.String));
            dt.Columns.Add(dc1);

            DataColumn dc2 = new DataColumn("mail", typeof(System.String));
            dt.Columns.Add(dc2);

            DataColumn dc3 = new DataColumn("blog", typeof(System.String));
            dt.Columns.Add(dc3);


            for (int i = 0; i < 50; i++)
            {
                DataRow dr = dt.NewRow();
                dr[0] = "下里巴人simple";
                dr[1] = "524300045@qq.com";
                dr[2] = "msdn" + i.ToString();
                dt.Rows.Add(dr);
            }
            comCheckBoxList1.DataSource = dt;
            comCheckBoxList1.DisplayMember = "weibo";
            comCheckBoxList1.ValueMember = "mail";
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //添加项
            comCheckBoxList2.AddItems("邮箱:524300045@qq.com");
            comCheckBoxList2.AddItems("微博:下里巴人simple");
        }  至此,第二步骤已经完成,可以实现大部分功能了.

   3.事件处理

     这里我们定义下全选事件,取消事件,和某项选中状态更改时发生的事件

   

[csharp]
//全选事件  
      private void lbSelectAll_Click(object sender, EventArgs e) 
      { 
          for (int i = 0; i < checkListBox.Items.Count; i++) 
          { 
              checkListBox.SetItemChecked(i, true); 
    &nbsp