comboBox和textBox支持内置的搜索提示功能，
在form的InitializeComponent()中添加如下语句：
//将数据添加到搜索范围
this.comboBox1.AutoCompleteCustomSource.AddRange(new string[] { "10.152.154.89", "10.152.154.90", "10.152.252.10", "10.152.252.11" });
默认是None,还有Append,和SuggestAppend属性，除了默认的None都可以实现搜索提示的功能
this.comboBox1.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Suggest;
this.comboBox1.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.CustomSource;
转自http://www.cnblogs.com/luomingui/archive/2010/03/17/1688188.html
但经过测试并不能实现真正的模糊查询，只能从左到右查询，所以还是得自己写一个：
private void comboBox1_TextUpdate(object sender, EventArgs e)
{
ComboBox cbBox = (ComboBox)sender;
List<string> listNew = new List<string>();
cbBox.Items.Clear();
foreach (var item in listCell) //已有数据
{
if (item.Contains(cbBox.Text))
{
listNew.Add(item);
}
}
cbBox.Items.AddRange(listNew.ToArray());
cbBox.SelectionStart = cbBox.Text.Length;
Cursor = Cursors.Default;
cbBox.DroppedDown = true;
}