c#模仿百度关键词提示

本文主要是介绍c#模仿百度关键词提示，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

1：from窗体环境：TextBox(关键词文本框)、ListBox(提示框)

2：实现思路：

2.1：以输入的关键词为条件查询数据库（在查询中以点击率排序就加一个order by 点击率 desc）返回多行单列数据结果集合。再一一赋值到listBox中显示。

2.2：在TextBox中如果侦听键盘

if(Down（小键盘向下）)

则先获取到ListBox选中的索引，如果返回-1 或者x+1的值大于ListBox.count() 则初始值=0; 否则为ListBox索引值为x+1

else (Up(小键盘向上))

则先获取到ListBox选中的索引，如果返回-1 或者x-1的值< 0 则初始值=ListBox.count() ; 否则为ListBox索引值为x-1;

3：窗体代码如下

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;
using System.IO;
using System.IO.Ports;
using System.Text.RegularExpressions;
using System.Text;
/// <summary>
///     <author>hubiao</author>
///	<date>2014-07-30</date>
/// </summary>
namespace ee
{
/// <summary>
/// Description of MainForm.
/// </summary>
public partial class MainForm : Form
{
private List<String> dataBuffer = new List<String>();
public MainForm()
{
InitializeComponent();
//程序与from窗体分离执行
Control.CheckForIllegalCrossThreadCalls = false;
}
void Button1Click(object sender, System.EventArgs e)
{
textBox1.Text = String.Empty;
}
//这里可以从数据库初始化值
void MainFormLoad(object sender, EventArgs e)
{
dataBuffer.Add("心态");
dataBuffer.Add("信心");
dataBuffer.Add("能核心");
dataBuffer.Add("醉心能");
dataBuffer.Add("linuax");
dataBuffer.Add("linuax改变IT世界");
dataBuffer.Add("java");
dataBuffer.Add("java是点亮星星之火");
dataBuffer.Add("linaux改变IT世界");
dataBuffer.Add("java");
dataBuffer.Add("java是星星");
dataBuffer.Add("湖北省");
dataBuffer.Add("湖北跨省");
dataBuffer.Add("湖北武汉");
dataBuffer.Add("咸宁也是湖北的");
dataBuffer.Add("这是核桃");
dataBuffer.Add("通城属于咸宁的");
dataBuffer.Add("今天是星期几？");
//先隐藏！
listBox1.Hide();
}
//检索出值
bool isFjty = false;
void TextBox2TextChanged(object sender, EventArgs e)
{
TextBox tb = sender as TextBox;
if(isFjty)
return;
String outStr = tb.Text;
if(outStr==""){
listBox1.Hide();
return;
}else
listBox1.Show();
listBox1.Items.Clear();
foreach(String db in dataBuffer)
{
/*方案1：包含提示  
if(db.IndexOf(outStr)!=-1)
{
listBox1.Items.Add(db);
}*/
/*方案2：从前向后匹配
if(db.StartsWith(outStr))
{
listBox1.Items.Add(db);
}*/
}
int count = listBox1.Items.Count;
if(count > 0)
listBox1.Height = (count+1)*13;
else
TextBox2Leave(null,null);
}
Keys keys;
void ListBox1KeyDown(object sender, KeyEventArgs e)
{
keys = e.KeyCode;
textBox1.AppendText("key="+keys);
}
void TextBox2KeyUp(object sender, KeyEventArgs e)
{
Keys keys = e.KeyCode;
textBox1.Text = keys.ToString();
if(keys.ToString()=="Down" && listBox1.Items.Count > 0){
isFjty = true;
int x = listBox1.SelectedIndex;
x = x==-1?0:x+1;
if(x > listBox1.Items.Count-1)
x = 0;
listBox1.SelectedIndex = x;
textBox2.Text = listBox1.Items[x].ToString();
textBox2.SelectionStart = textBox2.Text.Length+1;
}else if(keys.ToString()=="Up" && listBox1.Items.Count > 0){
isFjty = true;
int x = listBox1.SelectedIndex;
int len = listBox1.Items.Count-1;
x = x==-1?len:x-1;
if(x < 0)
x = len;
listBox1.SelectedIndex = x;
textBox2.Text = listBox1.Items[x].ToString();
textBox2.SelectionStart = textBox2.Text.Length+1;
}else{
isFjty = false;
}
}
/*按下键时，如果不是上下移动，则立即侦听输入的字符*/
void TextBox2KeyDown(object sender, KeyEventArgs e)
{
if(keys.ToString()!="Down" || keys.ToString()!="Up")
{
isFjty = false;
}
}
/*鼠标手动选择*/
void ListBox1Click(object sender, EventArgs e)
{
textBox2.Text = listBox1.Items[listBox1.SelectedIndex].ToString();
textBox2.SelectionStart = textBox2.Text.Length+1;
textBox2.Focus();
//手动选择后，是否应该隐藏掉提示列表呢？
//TextBox2Leave(null,null);
}
//关键输入框失去焦点后就【隐藏提示列表】。
void TextBox2Leave(object sender, EventArgs e)
{
listBox1.Items.Clear();
listBox1.Height = 0;
listBox1.Hide();
}
}
}

4：示例图

|--从前向后匹配