本文内容：
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概述：
本文描述了如何建立一个简单的、常用的用户控件——地址栏。
相信只要上网的朋友，都知道IE里面有一个提供大家输入你想去的网站的输入框。在该输入框中，你只需要输入部分字符，它在其下拉列表框中，就显示出来与你所输入相关的内容(记忆功能)。
如果只要求输入字符串就可以的话。那么，我们可以直接使用TextBox等控件完成输入框。但如果你要让你的输入框有记忆功能的话。那么，我们所需要的就是要求能把以前所输入的内容读取出来。
好了，废话说了半天了。那么，我们从下面开始讲解如何让我们的地址栏有记忆功能的。
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建立自己的地址栏：
首先，我们要分两步走。
第一步，我们首先要明白，我们IE地址栏的历史记忆内容是从哪来的。因为只有知道它是从哪来的，我们才能明白我们的数据嘛。
那么，我们先看一下，IE在regedit(注册表)里面都有些什么内容。因为regeidt是Windows里面一个非常不错的数据库(^_^)，它可以把整台机子相关的一些东西都存放在里面。
在regedit里面，与IE相关的内容有这些：
当然，这只是一部分，还有一部分是：
我们要的是第一幅图片里面的“Software\Microsoft\Internet Explorer\TypedURLs”的数据。不然，我们写的记忆功能就起不了什么作用了。或者，出现一些其它数据。要知道，在regedit里面保存的数据可都是一些关键数据。如果一不小心被人XX掉的话，那么，L。
OK，现在已经找到我们要的数据是从什么地方来的了。那么，我们就要开始打造我们自己的带记忆功能的地址栏了。
当然，打到这些够了吗？当然，够是够了。但，你不想让你的地址栏功能再强大一点吗？那么，我们写这样的一个类来看看：
1、 新建项目，选择新建类库，名字就顺意了。比如：ControlSet.URLControl。
2、 在资源管理里面添加引用System.Windows.Forms.dll。
3、 然后，在资源管理器里面把Class1.cs改为UnManagedMethods.cs，然后，用下面的代码替换：
using System;
using System.Runtime.InteropServices;
namespace ControlSet.URLControl
{
[StructLayout(LayoutKind.Sequential)]
internal struct Rect
{
public int left;
public int top;
public int right;
public int bottom;
}
[StructLayout(LayoutKind.Sequential)]
internal struct ComboBoxInfo
{
public int cbSize;
public Rect rcItem;
public Rect rcButton;
public IntPtr stateButton;
public IntPtr hwndCombo;
public IntPtr hwndEdit;
public IntPtr hwndList;
}
/// <summary>
/// All unmanaged DllImport methods used in this assembly
/// </summary>
internal class UnManagedMethods
{
[DllImport("User32.dll")]
internal static extern bool GetComboBoxInfo(IntPtr hwndCombo, ref ComboBoxInfo info);
[DllImport("Shlwapi.dll")]
internal static extern void SHAutoComplete(IntPtr hwnd, IntPtr flags);
}
}
第二步，我们的地址栏出现了。那么，要用什么做为它的基控件呢？
因为我们要有记忆功能，那么，当然，要有一个能下拉的东西了。什么？ComboBox就是最好的选择。那好，我们开始用ComboBox来构建我们自己的控件。
namespace ControlSet.URLControl
{
/// <summary>
/// A control that extends the regular combo box to show URLs.
/// </summary>
public class URLComboBox : ComboBox
{
/// <summary>
/// Initilaizes a new instance of URLComboBox
/// </summary>
public URLComboBox() : base()
{
}
}
}
首先，我们添加如下引用：
using Microsoft.Win32;
在该控件内要用到下面一些东西，我们给它添加如下代码(添加到命名空间里面)：
/// <summary>
/// A simple enumeration that wraps various auto complete flags of SHAutoComplete.
/// See documenation of SHAutoComplete for details
/// </summary>
[Flags]
public enum AutoCompleteFlags : int
{
/// <summary>
/// This includes the File System as well as the rest of the shell (Desktop\My Computer\Control Panel\)
/// </summary>
FileSystem = 0x00000001,
/// <summary>
/// URLs in the User's History
/// </summary>
URLHistory = 0x00000002,
/// <summary>
/// URLs in the User's Recently Used list.
/// </summary>
URLMRU = 0x00000004,
/// <summary>
/// Use the tab to move thru the autocomplete possibilities instead of to the next dialog/window control.
/// </summary>
UseTab = 0x00000008,
/// <summary>
/// This includes the File System
/// </summary>
FileSystemOnly = 0x00000010,
/// <summary>
/// Same as FileSystemOnly except it only includes directories, UNC servers, and UNC server shares.
/// </summary>
FileSystemDirs = 0x00000020,
/// <summary>
/// Ignore the registry default and force the auto suggest feature on.
/// </summary>
AutoSuggestForceOn = 0x10000000,
/// <summary>
/// Ignore the registry default and force the auto suggest feature off
/// </summary>
AutoSuggestForceOff = 0x20000000,
/// <summary>
/// Ignore the registry default and force the auto append on.
/// </summary>
AutoAppendForceOn = 0x40000000,
/// <summary>
/// Ignore the registry default and force auto append off.
/// </summary>
AutoAppendForceOff = -2147483648
}
/// <summary>
/// Enumeration for possible types of registry base keys for storing most recntly typed URLs
/// </summary>
public enum MRUKeyHive : int
{
/// <summary>
/// Value that indicates HKEY_CURRENT_USER should be used for MRUKey property
/// </summary>
CurrentUser = 1,
/// <summary>
/// Value that indicates HKEY_LOCAL_MACHINE should be used for MRUKey property
/// </summary>
LocalMachine = 2,
}
然后，再在该类里面加载如下代码来完成它应该有的功能：
/// <summary>
/// A control that extends the regular combo box to show URLs.
/// </summary>
public class URLComboBox : ComboBox
{
/// <summary>
/// Member variable which stores the autocomplete flags
/// </summary>
private AutoCompleteFlags _flags = AutoCompleteFlags.FileSystem | AutoCompleteFlags.URLHistory | AutoCompleteFlags.URLMRU;
/// <summary>
/// Member variable which stores the mru key
/// </summary>
private string _mruKey = @"Software\Microsoft\Internet Explorer\TypedURLs";
/// <summary>
/// Member variable which stores the mru key hive
/// </summary>
private MRUKeyHive _mruKeyHive = MRUKeyHive.CurrentUser;
/// <summary>
/// Initilaizes a new instance of URLComboBox
/// </summary>
public URLComboBox() : base()
{
}
/// <summary>
/// Gets the registry key where MRU URLs are stored
/// </summary>
/// <param name="writable">Indicates whether to get the key so that it values written to it</param>
/// <returns>RegistryKey object for the MRU registry key or null if none exists</returns>
private RegistryKey GetMRUKey(bool writable)
{
if (_mruKey.Length == 0)
return null;
RegistryKey ret = null;
switch(_mruKeyHive)
{
case MRUKeyHive.LocalMachine:
ret = Registry.LocalMachine.OpenSubKey(_mruKey, writable);
break;
case MRUKeyHive.CurrentUser:
ret = Registry.CurrentUser.OpenSubKey(_mruKey, writable);
break;
}
return ret;
}
/// <summary>
/// Writes information about any ignored exception to the trace.
/// </summary>
/// <param name="e">The exception which is being ignored</param>
private void TraceIgnoredError(Exception e)
{
//It's ok if there is any error
System.Diagnostics.Trace.WriteLine(e.Message);
System.Diagnostics.Trace.WriteLine(e.StackTrace);
}
/// <summary>
/// Utility function to fill the combob box most recently typed URLs read from registry.
/// </summary>
private void MRUFill()
{
if (DesignMode)
return;
RegistryKey mruKey = null;
try
{
int i = 1;
string strFormat = "url{0}";
object defaultValue = String.Empty;
object url;
mruKey = GetMRUKey(false);
if (mruKey != null)
{
while((url = mruKey.GetValue(String.Format(strFormat, i), defaultValue)) != defaultValue)
{
Items.Add(url);
i++;
}
}
}
catch(Exception e)
{
TraceIgnoredError(e);
}
finally
{
if (mruKey != null)
mruKey.Close();
}
}
/// <summary>
/// Gets or sets the auto complete flags
/// </summary>
[Description("Gets or sets the auto complete flags")]
public AutoCompleteFlags Flags
{
get
{
return _flags;
}
set
{
_flags = value;
}
}
/// <summary>
/// Gets or sets the registry key name where the combo box maintains MRU list.
/// </summary>
[DescriptionAttribute("The registry key name where the combo box maintains MRU list")]
public string MRUKey
{
get
{
return _mruKey;
}
set
{
_mruKey = value;
}
}
/// <summary>
/// Gets or sets the registry key hive for the MRUKey property.
/// </summary>
[DescriptionAttribute("The registry hive where the combo box maintains MRU list")]
public MRUKeyHive MRUKeyHive
{
get
{
return _mruKeyHive;
}
set
{
_mruKeyHive = value;
}
}
/// <summary>
/// Writes the recntly typed URL to the registry if it is not already there
/// </summary>
/// <param name="e"></param>
protected override void OnValidated(System.EventArgs e)
{
if (DesignMode)
return;
if ((Text.Length != 0) && (Items.IndexOf(Text) == -1))
{
Items.Add(Text);
RegistryKey mruKey = null;
//Finally add it to the registry
try
{
mruKey = GetMRUKey(true);
if (mruKey != null)
mruKey.SetValue(String.Format("url{0}", Items.Count), Text);
}
catch(Exception ex)
{
TraceIgnoredError(ex);
}
finally
{
if (mruKey != null)
mruKey.Close();
}
}
base.OnValidated(e);
}
/// <summary>
/// Finds the handle to the edit control and calls SHAutoComplete on it.
/// Also fills the combobox from the values read from the registry
/// </summary>
/// <param name="e">Ignored</param>
protected override void OnHandleCreated(System.EventArgs e)
{
base.OnHandleCreated(e);
if (DesignMode)
return;
//This is the right place do auto completion
ComboBoxInfo info = new ComboBoxInfo();
info.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(info);
if (UnManagedMethods.GetComboBoxInfo(Handle, ref info))
{
UnManagedMethods.SHAutoComplete(info.hwndEdit, (IntPtr)_flags);
}
MRUFill();
}
}
好了，那么，到现在为止。我们的带记忆功能的地址栏已经构建完成。
你可以在菜单【生成(B)】里面，调试生成解决方案。
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建立示例程序：
1、 新建项目，选择Windows应用程序，名称：TestrulComboBox。
2、 我们把我们所需要的控件放到工具箱里面。在工具箱上面点右键。添加/移除项。打开Com组件。如下图：
3、 再把我们自己写的控件也放到工具箱里面。如上图，点击里面的浏览按钮。找到你上一个解决方案存放的目录，然后，找出它所生成的动态链接库文件。就可以直接添加到工具箱上面了。
4、 在现有的项目内，把拖放刚才添加到工具箱上面的Microsoft Web 浏览器控件，和刚才刚才写好的控件，拖放到主窗口上面。并进行排列。
5、 添加一个控钮。
6、 双击按钮，生成事件，并在事件中输入如下代码：
Cursor currentCursor = Cursor.Current;
try
{
Cursor.Current = Cursors.WaitCursor;
object arg1 = 0; object arg2 = ""; object arg3 = ""; object arg4 = "";
axWebBrowser1.Navigate(urlComboBox1.Text,ref arg1,ref arg2, ref arg3, ref arg4);
}
finally
{
Cursor.Current = currentCursor;
}
7、 生成解决方案。
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最后：
好了，你也可以自己试着做一个自己的、个性化的浏览器了。如果还想再加其他功能的话。那就不属于这一篇文章的目的了。J
