通过继承系统的ComboBox，写一个新控件ComboBoxEx，重写它的焦点以及文本更新事件，就可以轻松实现拼音首字母检索了。例如：输入 gd ，就可以出现“广东”。
1
using System;
2using System.Collections.Generic;
3using System.Text;
4using System.Windows.Forms;
5using System.Collections;
6
7namespace PrintDoc
8
{
9
public class ComboBoxEx : ComboBox
10
{
11 private ArrayList m_list = new ArrayList();
12
13 protected override void OnEnter(EventArgs e)
14 {
15 m_list.Clear();
16 m_list.AddRange(this.Items);
17 base.OnEnter(e);
18
}
19
20 protected override void OnLeave(EventArgs e)
21 {
22 this.Items.Clear();
23 this.Items.AddRange(m_list.ToArray());
24 base.OnLeave(e);
25 }
26
27 protected override void OnTextUpdate(EventArgs e)
28 {
29 while (this.Items.Count > 0)
30 {
31 this.Items.RemoveAt(0);
32 }
33 foreach (object o in this.m_list)
34 {
35 if ( GetChineseSpell(o.ToString()).ToLower().Contains(this.Text.ToLower()))
36 {
37 this.Items.Add(o);
38 }
39 }
40 this.DroppedDown = true;
41 this.Cursor = Cursors.Default;
42 base.OnTextUpdate(e);
43 }
44
45 static public string GetChineseSpell(string strText)
46 {
47 int len = strText.Length;
48 string myStr = "";
49 for (int i = 0; i < len; i++)
50 {
51 myStr += getSpell(strText.Substring(i, 1));
52 }
53 return myStr;
54 }
55
56 static public string getSpell(string cnChar)
57 {
58 byte[] arrCN = Encoding.Default.GetBytes(cnChar);
59 if (arrCN.Length > 1)
60 {
61 int area = (short)arrCN[0];
62 int pos = (short)arrCN[1];
63 int code = (area << 8) + pos;
64 int[] areacode = { 45217, 45253, 45761, 46318, 46826, 47010, 47297, 47614, 48119, 48119, 49062, 49324, 49896, 50371, 50614, 50622, 50906, 51387, 51446, 52218, 52698, 52698, 52698, 52980, 53689, 54481 };
65 for (int i = 0; i < 26; i++)
66 {
67 int max = 55290;
68 if (i != 25) max = areacode[i + 1];
69 if (areacode[i] <= code && code < max)
70 {
71 return Encoding.Default.GetString(new byte[] { (byte)(65 + i) });
72 }
73 }
74 return "*";
75 }
76 else
77 return cnChar;
78 }
79 }
80
}
81
using System;2
using System.Collections.Generic;3
using System.Text;4
using System.Windows.Forms;5
using System.Collections;6
7
namespace PrintDoc8
{
9
public class ComboBoxEx : ComboBox10
{
11
private ArrayList m_list = new ArrayList();12
13
protected override void OnEnter(EventArgs e)14
{15
m_list.Clear();16
m_list.AddRange(this.Items);17
base.OnEnter(e);18
}19
20
protected override void OnLeave(EventArgs e)21
{22
this.Items.Clear();23
this.Items.AddRange(m_list.ToArray());24
base.OnLeave(e);25
}26
27
protected override void OnTextUpdate(EventArgs e)28
{29
while (this.Items.Count > 0)30
{31
this.Items.RemoveAt(0);32
}33
foreach (object o in this.m_list)34
{35
if ( GetChineseSpell(o.ToString()).ToLower().Contains(this.Text.ToLower()))36
{37
this.Items.Add(o);38
}39
}40
this.DroppedDown = true;41
this.Cursor = Cursors.Default;42
base.OnTextUpdate(e);43
}44
45
static public string GetChineseSpell(string strText)46
{47
int len = strText.Length;48
string myStr = "";49
for (int i = 0; i < len; i++)50
{51
myStr += getSpell(strText.Substring(i, 1));52
}53
return myStr;54
}55
56
static public string getSpell(string cnChar)57
{58
byte[] arrCN = Encoding.Default.GetBytes(cnChar);59
if (arrCN.Length > 1)60
{61
int area = (short)arrCN[0];62
int pos = (short)arrCN[1];63
int code = (area << 8) + pos;64
int[] areacode = { 45217, 45253, 45761, 46318, 46826, 47010, 47297, 47614, 48119, 48119, 49062, 49324, 49896, 50371, 50614, 50622, 50906, 51387, 51446, 52218, 52698, 52698, 52698, 52980, 53689, 54481 };65
for (int i = 0; i < 26; i++)66
{67
int max = 55290;68
if (i != 25) max = areacode[i + 1];69
if (areacode[i] <= code && code < max)70
{71
return Encoding.Default.GetString(new byte[] { (byte)(65 + i) });72
}73
}74
return "*";75
}76
else 77
return cnChar;78
}79
}80
}81
用来进行语法转化的工具：http://codeconverter.sharpdevelop.net/SnippetConverter.aspx
转化之后的VB.NET版本如下。
1 Public Shared Function getHzPy(ByVal cnChar As String) As String
2 Dim arrCN As Byte() = System.Text.Encoding.[Default].GetBytes(cnChar)
3 If arrCN.Length > 1 Then
4 Dim area As Integer = CShort(arrCN(0))
5 Dim pos As Integer = CShort(arrCN(1))
6 Dim code As Integer = (area << 8) + pos
7 Dim areacode As Integer() = {45217, 45253, 45761, 46318, 46826, 47010, _
8 47297, 47614, 48119, 48119, 49062, 49324, _
9 49896, 50371, 50614, 50622, 50906, 51387, _
10 51446, 52218, 52698, 52698, 52698, 52980, _
11 53689, 54481}
12 For i As Integer = 0 To 25
13 Dim max As Integer = 55290
14 If i <> 25 Then
15 max = areacode(i + 1)
16 End If
17 If areacode(i) <= code AndAlso code < max Then
18 Return System.Text.Encoding.[Default].GetString(New Byte() {CByte((65 + i))})
19 End If
20 Next
21 Return "*"
22 Else
23 Return cnChar
24 End If
25 End Function
Public Shared Function getHzPy(ByVal cnChar As String) As String2
Dim arrCN As Byte() = System.Text.Encoding.[Default].GetBytes(cnChar)3
If arrCN.Length > 1 Then4
Dim area As Integer = CShort(arrCN(0))5
Dim pos As Integer = CShort(arrCN(1))6
Dim code As Integer = (area << 8) + pos7
Dim areacode As Integer() = {45217, 45253, 45761, 46318, 46826, 47010, _8
47297, 47614, 48119, 48119, 49062, 49324, _9
49896, 50371, 50614, 50622, 50906, 51387, _10
51446, 52218, 52698, 52698, 52698, 52980, _11
53689, 54481}12
For i As Integer = 0 To 2513
Dim max As Integer = 5529014
If i <> 25 Then15
max = areacode(i + 1)16
End If17
If areacode(i) <= code AndAlso code < max Then18
Return System.Text.Encoding.[Default].GetString(New Byte() {CByte((65 + i))})19
End If20
Next21
Return "*"22
Else23
Return cnChar24
End If25
End Function
另外还有一篇相关的文章，除了计算拼音的算法不对之外，其他方面的事件考虑的比较周全。可以用上面的算法替换掉下面文章中的getHzPy方法。
http://blog.csdn.net/Flora_qxy/archive/2007/08/30/1764964.aspx
除此之外，再贴两篇和AucoCompleteComboBox相关的文章，看似很好很强大。
http://www.codeproject.com/KB/architecture/MultiColumnFlatCombo.aspx
