在Winfrom下实现类似百度、Google搜索自能提示功能

前记：数据源来自页面的一个ComboBox的数据源List<Contract>集合

页面放置一个TextBox(搜索框)、ListBox（显示搜索出来的数据），ListBox位置位于TextBox正下方，初始化隐藏。

TextBox--->txtSearch  ListBox--->listBox1关于两个控件的事件，详见代码：

#region  自能提示
        Point pList = new Point();

        private void txtSearch_TextChanged(object sender, EventArgs e)
        {
            if (this.txtSearch.Text.Trim() != "")
            {
                List<Contract> source = getDataTable(this.txtSearch.Text.Trim());
                BindList(source);
                this.listBox1.Visible = true;
            }
            else
            {
                this.listBox1.Items.Clear();
                this.listBox1.Visible = false;
            }
        }

        private void txtSearch_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Down && this.listBox1.Visible)
            {
                this.listBox1.Focus();

                if (this.listBox1.SelectedItems.Count > 0)
                {
                    this.listBox1.SetSelected(this.listBox1.SelectedIndex, false);
                }
                if (this.listBox1.Items.Count > 0)
                {
                    this.listBox1.SetSelected(0, true);

                }
            }
        }

        private void listBox1_MouseUp(object sender, MouseEventArgs e)
        {
            if (this.listBox1.SelectedItems.Count > 0)
            {
                this.txtSearch.Text = this.listBox1.Text;
                cboChoCont.Text = this.txtSearch.Text;
                this.listBox1.Visible = false;
                this.txtSearch.Focus();
            }
        }

        private void listBox1_MouseMove(object sender, MouseEventArgs e)
        {
            Point m = new Point(e.X, e.Y);
            int index = GetItemAt(this.listBox1, e.X, e.Y);
            if (this.listBox1.SelectedItems.Count > 0 && this.listBox1.SelectedIndex != index)
            {
                this.listBox1.SetSelected(this.listBox1.SelectedIndex, false);
            }

            if (index != -1 && this.listBox1.SelectedIndex != index)
            {

                this.listBox1.SetSelected(index, true);
            }
        }

        private void listBox1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter && this.listBox1.Visible && this.listBox1.SelectedItems.Count > 0)
            {
                this.txtSearch.Text = this.listBox1.SelectedItems[0].ToString();
                this.cboChoCont.Text = this.txtSearch.Text;
                this.listBox1.Visible = false;
                this.txtSearch.Focus();
            }
        }

        private bool GetItemAt(Point Mousep, int index)
        {
            int ph = this.listBox1.GetItemHeight(index) * index;
            int ph1 = this.listBox1.GetItemHeight(index) * index + this.listBox1.GetItemHeight(index);

            if (Mousep.Y > ph && Mousep.Y < ph1 && Mousep.X > 0 && Mousep.X < this.listBox1.Width)
            {
                return true;
            }
            else
            {
                return false;
            }


        }
        private int GetItemAt(ListBox listBox, int X, int Y)
        {
            int index = -1;
            for (int i = 0; i < listBox.Items.Count; i++)
            {
                System.Drawing.Rectangle r = listBox.GetItemRectangle(i);
                if (r.Contains(new Point(X, Y)))
                {
                    index = i; ;
                    break;
                }
            }
            return index;
        }

        private void BindList(List<Contract> source)
        {
            this.listBox1.Items.Clear();
            for (int i = 0; i < source.Count; i++)
            {
                this.listBox1.Items.Add(source[i].Con_Name_Serial);
            }
            if (source.Count < 11)
            {
                this.listBox1.Height = 15 * source.Count + 15;
            }
            else
            {
                this.listBox1.Height = 150;
            }
            this.listBox1.Visible = true;
        }


        private List<Contract> getDataTable(string s)
        {
            List<Contract> searchList = new List<Contract>();
            int length = list.Count;
            for (int i = 0; i < length; i++)
            {
                if (list[i].Con_Name_Serial.IndexOf(s) == 0)
                    searchList.Add(list[i]);
            }
            return searchList;
        }

        private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
        {
            // Set the DrawMode property to draw fixed sized items.
            listBox1.DrawMode = DrawMode.OwnerDrawFixed;
            // Draw the background of the ListBox control for each item.
            e.DrawBackground();
            // Define the default color of the brush as black.
            Brush myBrush = Brushes.Black;
            FontFamily fontFamily = new FontFamily("宋体");
            System.Drawing.Font myFont = new Font(fontFamily, 9);
            // Determine the color of the brush to draw each item based on the index of the item to draw.
            if((e.State & DrawItemState.Selected) == DrawItemState.Selected)
            {
                //e.Graphics.FillRectangle(Brushes.Blue, e.Bounds);
                if(e.Index > -1)
                {
                    e.Graphics.DrawString(listBox1.Items[e.Index].ToString(), myFont, Brushes.White, e.Bounds, StringFormat.GenericDefault);
                }
            }
            else
            {
                //e.Graphics.FillRectangle(Brushes.White, e.Bounds);
                if(e.Index > -1)
                {
                    e.Graphics.DrawString(listBox1.Items[e.Index].ToString(), myFont, myBrush, e.Bounds, StringFormat.GenericDefault);
                }
            }
            // Draw the current item text based on the current Font and the custom brush settings.
            //e.Graphics.DrawString(listBox1.Items[e.Index].ToString(), e.Font, myBrush, e.Bounds, StringFormat.GenericDefault);


            // If the ListBox has focus, draw a focus rectangle around the selected item.
            e.DrawFocusRectangle();
        }
        #endregion

 转载来自：http://blog.csdn.net/Rock870210/article/details/5856235