Mikel
来源： .Net Winform开发笔记（三） 谈谈自制控件 – 周见智 – 博客园
末日这天写篇博客吧，既然没来，那就纪念一下。
这次谈谈自制控件，也就是自定义控件，先上图，再说
1.扩展OpenFileDialog，在OpenFileDialog中添加各种文件（.txt,.jpg,.excel等等）的预览功能
2.重写ListBox，增加折叠、鼠标背影、分类等功能
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一、扩展OpenFileDialog
许多软件的打开对话框都有预览功能，最常见的就是图片预览，用鼠标选择一个图片文件后，右侧或者下侧就会有该图片的缩略图（photoshop中属于后者）。在winform编程中，有专门的打开文件对话框的类OpenFileDialog，但是他不提供文件预览功能，封装得实在太好。看看它公开那些接口
提到扩展，很多人可能想到继承它就可以扩展它，可惜OpenFileDialog声明为sealed，不允许从他继承。稍微底层一点的，想到可以通过Win32 API来修改它的显示方式，只可惜，如你所见，它根本没提供Handle属性，更别说HandleCreated、HandleDestroyed等事件了。那么怎么样子搞呢？其实答案还是通过Win32 API，只是我们取得它的句柄的方式要复杂一点而且调用API的时机隐晦了一点。
提示：
1.Win32 API操作窗体需要知道窗体的句柄；
2.不熟悉Win32编程的同学可以先上网查查资料，特别是不知道SetParent、SetWindowPos等API是干嘛的，我觉得以下的看不懂。
为什么说取得它的句柄复杂了一点？难道不是用“FindWindow”、“FindWindowEx”、“ EnumChildWindows”等获取OpenFileDialog的句柄，再用“SetParent”、“SetWindowPos”等API将.net控件（本例中是DataGridView控件，当然可以使其他任何一种）添加到OpenFileDialog中去？没错，以上列举出来的API都是基本要用到的，“只是用在什么地方、什么时候用”是个比较麻烦的问题，原因如下：
1）我们知道OpenfileDialog显示的是模式对话框，也就是说，一旦它ShowDialog（），它以下的代码是不会再执行的，具体原因是什么（我以后的博客会专门讲为什么），你现在可以理解为OpenFileDialog()方法会阻塞调用线程，既然阻塞了调用线程，那么我们再无法控制程序了（直到它返回），根本谈不上再调用API获取OpenFileDialog的句柄然后去操作它。如果有人会说，“我可以另开辟线程去取OpenFileDialog得句柄再操作它”，恩，我不否定这个方法，只是我想说，如果你真的按照这个方法去试，那么肯定会陷入泥潭。因为你不仅要取它的句柄，你还要监视OpenFIleDialog的一举一动，移动、缩放、用户鼠标点击选择文件、更改目录等，然后再操作.net控件（本例中是DataGridView控件，下同），让.net控件去适应OpenFileDialog的大小等等，你会发现你忙死了，甚至有的你根本监视不了，比如用户点击选择文件、更改目录。
2）就算我们能够在OpenFIleDialog显示之后，取得它的句柄，那么什么时候再调用其他API呢？比如什么时候调用SetWindowPos，让.net控件适应OpenFileDialog的大小变化？什么时候知道用户选择文件发生了变化？
所以，API方法什么时候用？用在什么地方？就是接下来要讨论的东西。
我不知道各位在使用各种框架的时候，对“框架”的理解到什么程度，我觉得可以总结成一句话“跟个2b似地注册一些事件，然后苦逼地去写好每一个回调方法，我们却不知道为啥要这样写”，不是么？既然这样，那么我们的API方法只要写在了正确的回调方法中，我们就能到达想要的目的了。考虑几个问题：
1）OpenFileDialog显示，我们向其中添加.net控件。我们什么时候知道它显示？
2）OpenFileDialog大小发生变化时，我们要更新.net控件以适应新的大小。我们什么时候知道OpenFileDialog的大小发生了变化？
3）OpenFileDialog中用户选择的文件发生了变化，我们需要知道新选择的文件路径，用来显示在.net控件中。我们怎么知道选择了什么文件？（这里选择文件指用户用鼠标在OpenFileDialog中单击选取，不是点击“确定”后。）
以上所有的问题，其实在一个地方都可以知道，那就是监听OpenFileDialog窗体的Windows消息，因为一个窗体的任何一个动作都伴随着一系列的Windows消息（这个可以用Spy++查看）。既然这样，那么我们可以在窗体处理Windows消息的回调方法中调用API方法了，也就是窗体的Control.WndProc方法中。之前已经说过了，OpenFileDialog声明为Sealed，提供的接口少之又少，我们几乎根本不可能接触到OpenFileDialog的WndProc，更谈不上监听Windows消息，然后调用API去操作它。这时候，NativeWindow该出场了，先来引用一下MSDN上对NativeWindow的解释：
“提供窗口句柄和窗口过程的低级封装。”
说了像没说一样，其实就是说，将一个窗口句柄与NativeWindow对象绑定后，该NativeWindow对象就能接收到这个窗体的所有消息。说到Windows消息，我想说一下Windows桌面应用程序的运行流程，其实如果看了我前一篇博客的同学应该有些了解，.Net Winform开发笔记（二）中基本提到了一些。为了配合本次讲解，我再次画了一张图
上图中，虚线框可以看做是一个.net中的Control类对象（或者其派生类，下同，控件即窗体、窗体即控件），正常情况下，Winform程序会按照1->2->3的步骤运行，当我们将Control类对象的Handle（就是我们常说的窗口句柄，做了一下封装）与一个NativeWIndow对象绑定后，程序不再按照1->2->3这样的顺序运行了，他会按照1->2-1->2-2->3这样运行，也就是说，NativeWindow对象可以拦截Control类对象的WIndows消息，我们完全可以在NativeWIndow中重写他的WndProc方法，像处理自己的Windows消息一样去处理Control类对象的消息。所以，我们就可以在NativeWindow对象的WndProc中调用我们的API方法。
接下来，上代码（代码只提供大概思路）
1.扩展对话框
View Code
1 public class MultiOpenFileDialog
2 {
3 #region fields
4 private const SetWindowPosFlags UFLAGSHIDE =
5 SetWindowPosFlags.SWP_NOACTIVATE |
6 SetWindowPosFlags.SWP_NOOWNERZORDER |
7 SetWindowPosFlags.SWP_NOMOVE |
8 SetWindowPosFlags.SWP_NOSIZE |
9 SetWindowPosFlags.SWP_HIDEWINDOW;
10 #endregion
11 public string FileName;
12 #region public methods
13 public DialogResult ShowDialog()
14 {
15 return ShowDialog(null);
16 }
17 public DialogResult ShowDialog(IWin32Window owner)
18 {
19 using (OpenFileDialog open = new OpenFileDialog())
20 {
21 MedianForm median = new MedianForm(open);
22 median.Show(owner);
23 Win32.SetWindowPos(median.Handle, IntPtr.Zero, 0, 0, 0, 0, UFLAGSHIDE); //隐藏中间窗体
24 DialogResult dialogresult = open.ShowDialog(median); //将median作为openfileDialog的owner
25 median.Close();
26 if (dialogresult == DialogResult.OK)
27 {
28 FileName = open.FileName;
29 }
30 return dialogresult;
31 }
32 }
33 #endregion
34 }
2.监听Dialog的NativeWindow
View Code
3.监听子控件的NativeWindow
View Code
1 class ChildControlNativeWindow : NativeWindow,IDisposable
2 {
3 IntPtr handle; //需要被监听消息的子控件句柄
4 public ChildControlNativeWindow(IntPtr handle)
5 {
6 this.handle = handle;
7 AssignHandle(handle);
8 }
9
10 #region override methods
11 protected override void WndProc(ref Message m)
12 {
13 switch (m.Msg)
14 {
15 case (int)Msg.WM_NOTIFY:
16 OFNOTIFY ofNotify = (OFNOTIFY)Marshal.PtrToStructure(m.LParam, typeof(OFNOTIFY));
17 if (ofNotify.hdr.code == (uint)DialogChangeStatus.CDN_SELCHANGE) //openfileDialog选择文件发生变化
18 {
19 StringBuilder file = new StringBuilder(256);
20 Win32.SendMessage(Win32.GetParent(handle), (int)DialogChangeProperties.CDM_GETFILEPATH, (int)256, file);
21 if (SelectFileChanged != null)
22 SelectFileChanged(file); //通知注册者
23 }
24 else if (ofNotify.hdr.code == (uint)DialogChangeStatus.CDN_FOLDERCHANGE) //openfileDialog选择目录发生变化
25 {
26 StringBuilder path = new StringBuilder(256);
27 Win32.SendMessage(Win32.GetParent(handle), (int)DialogChangeProperties.CDM_GETFOLDERPATH, (int)256, path);
28 if (SelectPathChanged != null)
29 SelectPathChanged(path); //通知注册者
30 }
31 break;
32 }
33 base.WndProc(ref m);
34 }
35 #endregion
36
37 #region delegate
38 public delegate void SelectFileChangedEventHandler(StringBuilder file);
39 public delegate void SelectPathChangedEventHandler(StringBuilder path);
40 #endregion
41
42 #region events
43 public event SelectFileChangedEventHandler SelectFileChanged; //当openfileDialog的选择文件发生变化时发生
44 public event SelectPathChangedEventHandler SelectPathChanged; //当openfileDialog的选择目录发生变化时发生
45 #endregion
46
47 #region IDisposable 成员
48
49 public void Dispose()
50 {
51 ReleaseHandle(); //终止与子控件句柄的关联
52 }
53
54 #endregion
55 }
4.中间过渡窗体，用来获取OpenFileDialog的句柄
View Code
1 class MedianForm : Form
2 {
3 OpenFileDialog open = null;
4 DialogNativeWindow dialognative;
5
6 public MedianForm(OpenFileDialog open)
7 {
8 this.open = open;
9 StartPosition = FormStartPosition.Manual;
10 Location = new System.Drawing.Point(-1000, -1000); //避免界面闪烁
11 }
12 protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
13 {
14 if (dialognative != null)
15 {
16 dialognative.Dispose(); //释放资源
17 }
18 base.OnClosing(e);
19 }
20 protected override void WndProc(ref Message m)
21 {
22 if (m.Msg == (int) Msg.WM_ACTIVATE)
23 {
24 dialognative = new DialogNativeWindow(m.LParam, open); //m.LParam为要打开的窗口句柄，开始监听OpenFileDialog的Windows消息
25 }
26 base.WndProc(ref m);
27 }
28 }
5.访问Excel文件的类
View Code
1 class OledbManager
2 {
3 OleDbConnection conn;
4 /// <summary>
5 /// 连接excel文件
6 /// </summary>
7 /// <param name="connstr"></param>
8 /// <returns></returns>
9 public bool Connect(string connstr)
10 {
11 try
12 {
13 conn = new OleDbConnection(connstr);
14 conn.Open();
15 return true;
16 }
17 catch
18 {
19 return false;
20 }
21 }
22 /// <summary>
23 /// 查找第一张表中的数据
24 /// </summary>
25 /// <returns></returns>
26 public DataTable SearchTable()
27 {
28 try
29 {
30 DataTable tb = new DataTable();
31 string sql = "select * from [Sheet1$]";
32 OleDbCommand com = new OleDbCommand(sql, conn);
33 OleDbDataAdapter adp = new OleDbDataAdapter(com);
34 adp.Fill(tb);
35 return tb;
36 }
37 catch
38 {
39 return null;
40 }
41 }
42 }
6.几个Win32结构体、枚举类型以及API声明（本代码参考CodeProject上的一篇文章）
View Code
1 public static class Win32
2 {
3 #region Delegates
4 public delegate bool EnumWindowsCallBack(IntPtr hWnd, int lParam);
5 #endregion
6
7 #region USER32
8 [DllImport("user32.dll", CharSet = CharSet.Auto)]
9 public static extern IntPtr GetParent(IntPtr hWnd);
10 [DllImport("User32.Dll")]
11 public static extern int GetDlgCtrlID(IntPtr hWndCtl);
12 [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
13 public static extern int MapWindowPoints(IntPtr hWnd, IntPtr hWndTo, ref POINT pt, int cPoints);
14 [DllImport("user32.dll", SetLastError = true)]
15 public static extern bool GetWindowInfo(IntPtr hwnd, out WINDOWINFO pwi);
16 [DllImport("User32.Dll")]
17 public static extern void GetWindowText(IntPtr hWnd, StringBuilder param, int length);
18 [DllImport("User32.Dll")]
19 public static extern void GetClassName(IntPtr hWnd, StringBuilder param, int length);
20 [DllImport("user32.Dll")]
21 public static extern bool EnumChildWindows(IntPtr hWndParent, EnumWindowsCallBack lpEnumFunc, int lParam);
22 [DllImport("user32.Dll")]
23 public static extern bool EnumWindows(EnumWindowsCallBack lpEnumFunc, int lParam);
24 [DllImport("User32.dll", CharSet = CharSet.Auto)]
25 public static extern bool ReleaseCapture();
26 [DllImport("user32.dll", CharSet = CharSet.Auto)]
27 public static extern IntPtr SetCapture(IntPtr hWnd);
28 [DllImport("user32.dll", CharSet = CharSet.Auto)]
29 public static extern IntPtr ChildWindowFromPointEx(IntPtr hParent, POINT pt, ChildFromPointFlags flags);
30 [DllImport("user32.dll", EntryPoint = "FindWindowExA", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]
31 public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
32 [DllImport("user32.dll")]
33 public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
34 [DllImport("user32.dll", CharSet = CharSet.Auto)]
35 public static extern int PostMessage(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
36 [DllImport("user32.dll", CharSet = CharSet.Auto)]
37 public static extern int PostMessage(IntPtr hWnd, int msg, int wParam, int lParam);
38 [DllImport("user32.dll", CharSet = CharSet.Auto)]
39 public static extern int SendMessage(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
40 [DllImport("user32.dll", CharSet = CharSet.Auto)]
41 public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, int lParam);
42 [DllImport("user32.dll", CharSet = CharSet.Auto)]
43 public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, StringBuilder param);
44 [DllImport("user32.dll", CharSet = CharSet.Auto)]
45 public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, char[] chars);
46 [DllImport("user32.dll", CharSet = CharSet.Auto)]
47 public static extern IntPtr BeginDeferWindowPos(int nNumWindows);
48 [DllImport("user32.dll", CharSet = CharSet.Auto)]
49 public static extern IntPtr DeferWindowPos(IntPtr hWinPosInfo, IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int Width, int Height, SetWindowPosFlags flags);
50 [DllImport("user32.dll", CharSet = CharSet.Auto)]
51 public static extern bool EndDeferWindowPos(IntPtr hWinPosInfo);
52 [DllImport("user32.dll", CharSet = CharSet.Auto)]
53 public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int Width, int Height, SetWindowPosFlags flags);
54 [DllImport("user32.dll")]
55 public static extern bool GetWindowRect(IntPtr hwnd, ref RECT rect);
56 [DllImport("user32.dll")]
57 public static extern bool GetClientRect(IntPtr hwnd, ref RECT rect);
58 #endregion
59 }
60
61 #region SWP_Flags
62 [Flags]
63 public enum SWP_Flags
64 {
65 SWP_NOSIZE = 0x0001,
66 SWP_NOMOVE = 0x0002,
67 SWP_NOZORDER = 0x0004,
68 SWP_NOACTIVATE = 0x0010,
69 SWP_FRAMECHANGED = 0x0020, /* The frame changed: send WM_NCCALCSIZE */
70 SWP_SHOWWINDOW = 0x0040,
71 SWP_HIDEWINDOW = 0x0080,
72 SWP_NOOWNERZORDER = 0x0200, /* Don't do owner Z ordering */
73
74 SWP_DRAWFRAME = SWP_FRAMECHANGED,
75 SWP_NOREPOSITION = SWP_NOOWNERZORDER
76 }
77 #endregion
78
79 #region DialogChangeStatus
80 public enum DialogChangeStatus : long
81 {
82 CDN_FIRST = 0xFFFFFDA7,
83 CDN_INITDONE = (CDN_FIRST - 0x0000),
84 CDN_SELCHANGE = (CDN_FIRST - 0x0001),
85 CDN_FOLDERCHANGE = (CDN_FIRST - 0x0002),
86 CDN_SHAREVIOLATION = (CDN_FIRST - 0x0003),
87 CDN_HELP = (CDN_FIRST - 0x0004),
88 CDN_FILEOK = (CDN_FIRST - 0x0005),
89 CDN_TYPECHANGE = (CDN_FIRST - 0x0006),
90 }
91 #endregion
92
93 #region DialogChangeProperties
94 public enum DialogChangeProperties
95 {
96 CDM_FIRST = (0x400 + 100),
97 CDM_GETSPEC = (CDM_FIRST + 0x0000),
98 CDM_GETFILEPATH = (CDM_FIRST + 0x0001),
99 CDM_GETFOLDERPATH = (CDM_FIRST + 0x0002),
100 CDM_GETFOLDERIDLIST = (CDM_FIRST + 0x0003),
101 CDM_SETCONTROLTEXT = (CDM_FIRST + 0x0004),
102 CDM_HIDECONTROL = (CDM_FIRST + 0x0005),
103 CDM_SETDEFEXT = (CDM_FIRST + 0x0006)
104 }
105 #endregion
106
107 #region ImeNotify
108 public enum ImeNotify
109 {
110 IMN_CLOSESTATUSWINDOW = 0x0001,
111 IMN_OPENSTATUSWINDOW = 0x0002,
112 IMN_CHANGECANDIDATE = 0x0003,
113 IMN_CLOSECANDIDATE = 0x0004,
114 IMN_OPENCANDIDATE = 0x0005,
115 IMN_SETCONVERSIONMODE = 0x0006,
116 IMN_SETSENTENCEMODE = 0x0007,
117 IMN_SETOPENSTATUS = 0x0008,
118 IMN_SETCANDIDATEPOS = 0x0009,
119 IMN_SETCOMPOSITIONFONT = 0x000A,
120 IMN_SETCOMPOSITIONWINDOW = 0x000B,
121 IMN_SETSTATUSWINDOWPOS = 0x000C,
122 IMN_GUIDELINE = 0x000D,
123 IMN_PRIVATE = 0x000E
124 }
125 #endregion
126
127 #region FolderViewMode
128 public enum FolderViewMode
129 {
130 Default = 0x7028,
131 Icon = Default + 1,
132 SmallIcon = Default + 2,
133 List = Default + 3,
134 Details = Default + 4,
135 Thumbnails = Default + 5,
136 Title = Default + 6,
137 Thumbstrip = Default + 7,
138 }
139 #endregion
140
141 #region Enum DialogViewProperty
142 public enum DefaultViewType
143 {
144 Icons = 0x7029,
145 List = 0x702b,
146 Details = 0x702c,
147 Thumbnails = 0x702d,
148 Tiles = 0x702e,
149 }
150 #endregion
151
152 #region ButtonStyle
153 public enum ButtonStyle : long
154 {
155 BS_PUSHBUTTON = 0x00000000,
156 BS_DEFPUSHBUTTON = 0x00000001,
157 BS_CHECKBOX = 0x00000002,
158 BS_AUTOCHECKBOX = 0x00000003,
159 BS_RADIOBUTTON = 0x00000004,
160 BS_3STATE = 0x00000005,
161 BS_AUTO3STATE = 0x00000006,
162 BS_GROUPBOX = 0x00000007,
163 BS_USERBUTTON = 0x00000008,
164 BS_AUTORADIOBUTTON = 0x00000009,
165 BS_PUSHBOX = 0x0000000A,
166 BS_OWNERDRAW = 0x0000000B,
167 BS_TYPEMASK = 0x0000000F,
168 BS_LEFTTEXT = 0x00000020,
169 BS_TEXT = 0x00000000,
170 BS_ICON = 0x00000040,
171 BS_BITMAP = 0x00000080,
172 BS_LEFT = 0x00000100,
173 BS_RIGHT = 0x00000200,
174 BS_CENTER = 0x00000300,
175 BS_TOP = 0x00000400,
176 BS_BOTTOM = 0x00000800,
177 BS_VCENTER = 0x00000C00,
178 BS_PUSHLIKE = 0x00001000,
179 BS_MULTILINE = 0x00002000,
180 BS_NOTIFY = 0x00004000,
181 BS_FLAT = 0x00008000,
182 BS_RIGHTBUTTON = BS_LEFTTEXT
183 }
184 #endregion
185
186 #region ZOrderPos
187 public enum ZOrderPos
188 {
189 HWND_TOP = 0,
190 HWND_BOTTOM = 1,
191 HWND_TOPMOST = -1,
192 HWND_NOTOPMOST = -2
193 }
194 #endregion
195
196 #region Static Control Styles
197 public enum StaticControlStyles : long
198 {
199 SS_LEFT = 0x00000000,
200 SS_CENTER = 0x00000001,
201 SS_RIGHT = 0x00000002,
202 SS_ICON = 0x00000003,
203 SS_BLACKRECT = 0x00000004,
204 SS_GRAYRECT = 0x00000005,
205 SS_WHITERECT = 0x00000006,
206 SS_BLACKFRAME = 0x00000007,
207 SS_GRAYFRAME = 0x00000008,
208 SS_WHITEFRAME = 0x00000009,
209 SS_USERITEM = 0x0000000A,
210 SS_SIMPLE = 0x0000000B,
211 SS_LEFTNOWORDWRAP = 0x0000000C,
212 SS_OWNERDRAW = 0x0000000D,
213 SS_BITMAP = 0x0000000E,
214 SS_ENHMETAFILE = 0x0000000F,
215 SS_ETCHEDHORZ = 0x00000010,
216 SS_ETCHEDVERT = 0x00000011,
217 SS_ETCHEDFRAME = 0x00000012,
218 SS_TYPEMASK = 0x0000001F,
219 SS_REALSIZECONTROL = 0x00000040,
220 SS_NOPREFIX = 0x00000080, /* Don't do "&" character translation */
221 SS_NOTIFY = 0x00000100,
222 SS_CENTERIMAGE = 0x00000200,
223 SS_RIGHTJUST = 0x00000400,
224 SS_REALSIZEIMAGE = 0x00000800,
225 SS_SUNKEN = 0x00001000,
226 SS_EDITCONTROL = 0x00002000,
227 SS_ENDELLIPSIS = 0x00004000,
228 SS_PATHELLIPSIS = 0x00008000,
229 SS_WORDELLIPSIS = 0x0000C000,
230 SS_ELLIPSISMASK = 0x0000C000
231 }
232 #endregion
233
234 #region Combo Box styles
235 public enum ComboBoxStyles : long
236 {
237 CBS_SIMPLE = 0x0001,
238 CBS_DROPDOWN = 0x0002,
239 CBS_DROPDOWNLIST = 0x0003,
240 CBS_OWNERDRAWFIXED = 0x0010,
241 CBS_OWNERDRAWVARIABLE = 0x0020,
242 CBS_AUTOHSCROLL = 0x0040,
243 CBS_OEMCONVERT = 0x0080,
244 CBS_SORT = 0x0100,
245 CBS_HASSTRINGS = 0x0200,
246 CBS_NOINTEGRALHEIGHT = 0x0400,
247 CBS_DISABLENOSCROLL = 0x0800,
248 CBS_UPPERCASE = 0x2000,
249 CBS_LOWERCASE = 0x4000
250 }
251 #endregion
252
253 #region Window Styles
254 public enum WindowStyles : long
255 {
256 WS_OVERLAPPED = 0x00000000,
257 WS_POPUP = 0x80000000,
258 WS_CHILD = 0x40000000,
259 WS_MINIMIZE = 0x20000000,
260 WS_VISIBLE = 0x10000000,
261 WS_DISABLED = 0x08000000,
262 WS_CLIPSIBLINGS = 0x04000000,
263 WS_CLIPCHILDREN = 0x02000000,
264 WS_MAXIMIZE = 0x01000000,
265 WS_CAPTION = 0x00C00000,
266 WS_BORDER = 0x00800000,
267 WS_DLGFRAME = 0x00400000,
268 WS_VSCROLL = 0x00200000,
269 WS_HSCROLL = 0x00100000,
270 WS_SYSMENU = 0x00080000,
271 WS_THICKFRAME = 0x00040000,
272 WS_GROUP = 0x00020000,
273 WS_TABSTOP = 0x00010000,
274 WS_MINIMIZEBOX = 0x00020000,
275 WS_MAXIMIZEBOX = 0x00010000,
276 WS_TILED = 0x00000000,
277 WS_ICONIC = 0x20000000,
278 WS_SIZEBOX = 0x00040000,
279 WS_POPUPWINDOW = 0x80880000,
280 WS_OVERLAPPEDWINDOW = 0x00CF0000,
281 WS_TILEDWINDOW = 0x00CF0000,
282 WS_CHILDWINDOW = 0x40000000
283 }
284 #endregion
285
286 #region Window Extended Styles
287 public enum WindowExStyles
288 {
289 WS_EX_DLGMODALFRAME = 0x00000001,
290 WS_EX_NOPARENTNOTIFY = 0x00000004,
291 WS_EX_TOPMOST = 0x00000008,
292 WS_EX_ACCEPTFILES = 0x00000010,
293 WS_EX_TRANSPARENT = 0x00000020,
294 WS_EX_MDICHILD = 0x00000040,
295 WS_EX_TOOLWINDOW = 0x00000080,
296 WS_EX_WINDOWEDGE = 0x00000100,
297 WS_EX_CLIENTEDGE = 0x00000200,
298 WS_EX_CONTEXTHELP = 0x00000400,
299 WS_EX_RIGHT = 0x00001000,
300 WS_EX_LEFT = 0x00000000,
301 WS_EX_RTLREADING = 0x00002000,
302 WS_EX_LTRREADING = 0x00000000,
303 WS_EX_LEFTSCROLLBAR = 0x00004000,
304 WS_EX_RIGHTSCROLLBAR = 0x00000000,
305 WS_EX_CONTROLPARENT = 0x00010000,
306 WS_EX_STATICEDGE = 0x00020000,
307 WS_EX_APPWINDOW = 0x00040000,
308 WS_EX_OVERLAPPEDWINDOW = 0x00000300,
309 WS_EX_PALETTEWINDOW = 0x00000188,
310 WS_EX_LAYERED = 0x00080000
311 }
312 #endregion
313
314 #region ChildFromPointFlags
315 public enum ChildFromPointFlags
316 {
317 CWP_ALL = 0x0000,
318 CWP_SKIPINVISIBLE = 0x0001,
319 CWP_SKIPDISABLED = 0x0002,
320 CWP_SKIPTRANSPARENT = 0x0004
321 }
322 #endregion
323
324 #region HitTest
325 public enum HitTest
326 {
327 HTERROR = (-2),
328 HTTRANSPARENT = (-1),
329 HTNOWHERE = 0,
330 HTCLIENT = 1,
331 HTCAPTION = 2,
332 HTSYSMENU = 3,
333 HTGROWBOX = 4,
334 HTSIZE = HTGROWBOX,
335 HTMENU = 5,
336 HTHSCROLL = 6,
337 HTVSCROLL = 7,
338 HTMINBUTTON = 8,
339 HTMAXBUTTON = 9,
340 HTLEFT = 10,
341 HTRIGHT = 11,
342 HTTOP = 12,
343 HTTOPLEFT = 13,
344 HTTOPRIGHT = 14,
345 HTBOTTOM = 15,
346 HTBOTTOMLEFT = 16,
347 HTBOTTOMRIGHT = 17,
348 HTBORDER = 18,
349 HTREDUCE = HTMINBUTTON,
350 HTZOOM = HTMAXBUTTON,
351 HTSIZEFIRST = HTLEFT,
352 HTSIZELAST = HTBOTTOMRIGHT,
353 HTOBJECT = 19,
354 HTCLOSE = 20,
355 HTHELP = 21
356 }
357 #endregion
358
359 #region Windows Messages
360 public enum Msg
361 {
362 WM_NULL = 0x0000,
363 WM_CREATE = 0x0001,
364 WM_DESTROY = 0x0002,
365 WM_MOVE = 0x0003,
366 WM_SIZE = 0x0005,
367 WM_ACTIVATE = 0x0006,
368 WM_SETFOCUS = 0x0007,
369 WM_KILLFOCUS = 0x0008,
370 WM_ENABLE = 0x000A,
371 WM_SETREDRAW = 0x000B,
372 WM_SETTEXT = 0x000C,
373 WM_GETTEXT = 0x000D,
374 WM_GETTEXTLENGTH = 0x000E,
375 WM_PAINT = 0x000F,
376 WM_CLOSE = 0x0010,
377 WM_QUERYENDSESSION = 0x0011,
378 WM_QUIT = 0x0012,
379 WM_QUERYOPEN = 0x0013,
380 WM_ERASEBKGND = 0x0014,
381 WM_SYSCOLORCHANGE = 0x0015,
382 WM_ENDSESSION = 0x0016,
383 WM_SHOWWINDOW = 0x0018,
384 WM_CTLCOLOR = 0x0019,
385 WM_WININICHANGE = 0x001A,
386 WM_SETTINGCHANGE = 0x001A,
387 WM_DEVMODECHANGE = 0x001B,
388 WM_ACTIVATEAPP = 0x001C,
389 WM_FONTCHANGE = 0x001D,
390 WM_TIMECHANGE = 0x001E,
391 WM_CANCELMODE = 0x001F,
392 WM_SETCURSOR = 0x0020,
393 WM_MOUSEACTIVATE = 0x0021,
394 WM_CHILDACTIVATE = 0x0022,
395 WM_QUEUESYNC = 0x0023,
396 WM_GETMINMAXINFO = 0x0024,
397 WM_PAINTICON = 0x0026,
398 WM_ICONERASEBKGND = 0x0027,
399 WM_NEXTDLGCTL = 0x0028,
400 WM_SPOOLERSTATUS = 0x002A,
401 WM_DRAWITEM = 0x002B,
402 WM_MEASUREITEM = 0x002C,
403 WM_DELETEITEM = 0x002D,
404 WM_VKEYTOITEM = 0x002E,
405 WM_CHARTOITEM = 0x002F,
406 WM_SETFONT = 0x0030,
407 WM_GETFONT = 0x0031,
408 WM_SETHOTKEY = 0x0032,
409 WM_GETHOTKEY = 0x0033,
410 WM_QUERYDRAGICON = 0x0037,
411 WM_COMPAREITEM = 0x0039,
412 WM_GETOBJECT = 0x003D,
413 WM_COMPACTING = 0x0041,
414 WM_COMMNOTIFY = 0x0044,
415 WM_WINDOWPOSCHANGING = 0x0046,
416 WM_WINDOWPOSCHANGED = 0x0047,
417 WM_POWER = 0x0048,
418 WM_COPYDATA = 0x004A,
419 WM_CANCELJOURNAL = 0x004B,
420 WM_NOTIFY = 0x004E,
421 WM_INPUTLANGCHANGEREQUEST = 0x0050,
422 WM_INPUTLANGCHANGE = 0x0051,
423 WM_TCARD = 0x0052,
424 WM_HELP = 0x0053,
425 WM_USERCHANGED = 0x0054,
426 WM_NOTIFYFORMAT = 0x0055,
427 WM_CONTEXTMENU = 0x007B,
428 WM_STYLECHANGING = 0x007C,
429 WM_STYLECHANGED = 0x007D,
430 WM_DISPLAYCHANGE = 0x007E,
431 WM_GETICON = 0x007F,
432 WM_SETICON = 0x0080,
433 WM_NCCREATE = 0x0081,
434 WM_NCDESTROY = 0x0082,
435 WM_NCCALCSIZE = 0x0083,
436 WM_NCHITTEST = 0x0084,
437 WM_NCPAINT = 0x0085,
438 WM_NCACTIVATE = 0x0086,
439 WM_GETDLGCODE = 0x0087,
440 WM_SYNCPAINT = 0x0088,
441 WM_NCMOUSEMOVE = 0x00A0,
442 WM_NCLBUTTONDOWN = 0x00A1,
443 WM_NCLBUTTONUP = 0x00A2,
444 WM_NCLBUTTONDBLCLK = 0x00A3,
445 WM_NCRBUTTONDOWN = 0x00A4,
446 WM_NCRBUTTONUP = 0x00A5,
447 WM_NCRBUTTONDBLCLK = 0x00A6,
448 WM_NCMBUTTONDOWN = 0x00A7,
449 WM_NCMBUTTONUP = 0x00A8,
450 WM_NCMBUTTONDBLCLK = 0x00A9,
451 WM_NCXBUTTONDOWN = 0x00AB,
452 WM_NCXBUTTONUP = 0x00AC,
453 WM_NCXBUTTONDBLCLK = 0x00AD,
454 WM_KEYDOWN = 0x0100,
455 WM_KEYUP = 0x0101,
456 WM_CHAR = 0x0102,
457 WM_DEADCHAR = 0x0103,
458 WM_SYSKEYDOWN = 0x0104,
459 WM_SYSKEYUP = 0x0105,
460 WM_SYSCHAR = 0x0106,
461 WM_SYSDEADCHAR = 0x0107,
462 WM_KEYLAST = 0x0108,
463 WM_IME_STARTCOMPOSITION = 0x010D,
464 WM_IME_ENDCOMPOSITION = 0x010E,
465 WM_IME_COMPOSITION = 0x010F,
466 WM_IME_KEYLAST = 0x010F,
467 WM_INITDIALOG = 0x0110,
468 WM_COMMAND = 0x0111,
469 WM_SYSCOMMAND = 0x0112,
470 WM_TIMER = 0x0113,
471 WM_HSCROLL = 0x0114,
472 WM_VSCROLL = 0x0115,
473 WM_INITMENU = 0x0116,
474 WM_INITMENUPOPUP = 0x0117,
475 WM_MENUSELECT = 0x011F,
476 WM_MENUCHAR = 0x0120,
477 WM_ENTERIDLE = 0x0121,
478 WM_MENURBUTTONUP = 0x0122,
479 WM_MENUDRAG = 0x0123,
480 WM_MENUGETOBJECT = 0x0124,
481 WM_UNINITMENUPOPUP = 0x0125,
482 WM_MENUCOMMAND = 0x0126,
483 WM_CTLCOLORMSGBOX = 0x0132,
484 WM_CTLCOLOREDIT = 0x0133,
485 WM_CTLCOLORLISTBOX = 0x0134,
486 WM_CTLCOLORBTN = 0x0135,
487 WM_CTLCOLORDLG = 0x0136,
488 WM_CTLCOLORSCROLLBAR = 0x0137,
489 WM_CTLCOLORSTATIC = 0x0138,
490 WM_MOUSEMOVE = 0x0200,
491 WM_LBUTTONDOWN = 0x0201,
492 WM_LBUTTONUP = 0x0202,
493 WM_LBUTTONDBLCLK = 0x0203,
494 WM_RBUTTONDOWN = 0x0204,
495 WM_RBUTTONUP = 0x0205,
496 WM_RBUTTONDBLCLK = 0x0206,
497 WM_MBUTTONDOWN = 0x0207,
498 WM_MBUTTONUP = 0x0208,
499 WM_MBUTTONDBLCLK = 0x0209,
500 WM_MOUSEWHEEL = 0x020A,
501 WM_XBUTTONDOWN = 0x020B,
502 WM_XBUTTONUP = 0x020C,
503 WM_XBUTTONDBLCLK = 0x020D,
504 WM_PARENTNOTIFY = 0x0210,
505 WM_ENTERMENULOOP = 0x0211,
506 WM_EXITMENULOOP = 0x0212,
507 WM_NEXTMENU = 0x0213,
508 WM_SIZING = 0x0214,
509 WM_CAPTURECHANGED = 0x0215,
510 WM_MOVING = 0x0216,
511 WM_DEVICECHANGE = 0x0219,
512 WM_MDICREATE = 0x0220,
513 WM_MDIDESTROY = 0x0221,
514 WM_MDIACTIVATE = 0x0222,
515 WM_MDIRESTORE = 0x0223,
516 WM_MDINEXT = 0x0224,
517 WM_MDIMAXIMIZE = 0x0225,
518 WM_MDITILE = 0x0226,
519 WM_MDICASCADE = 0x0227,
520 WM_MDIICONARRANGE = 0x0228,
521 WM_MDIGETACTIVE = 0x0229,
522 WM_MDISETMENU = 0x0230,
523 WM_ENTERSIZEMOVE = 0x0231,
524 WM_EXITSIZEMOVE = 0x0232,
525 WM_DROPFILES = 0x0233,
526 WM_MDIREFRESHMENU = 0x0234,
527 WM_IME_SETCONTEXT = 0x0281,
528 WM_IME_NOTIFY = 0x0282,
529 WM_IME_CONTROL = 0x0283,
530 WM_IME_COMPOSITIONFULL = 0x0284,
531 WM_IME_SELECT = 0x0285,
532 WM_IME_CHAR = 0x0286,
533 WM_IME_REQUEST = 0x0288,
534 WM_IME_KEYDOWN = 0x0290,
535 WM_IME_KEYUP = 0x0291,
536 WM_MOUSEHOVER = 0x02A1,
537 WM_MOUSELEAVE = 0x02A3,
538 WM_CUT = 0x0300,
539 WM_COPY = 0x0301,
540 WM_PASTE = 0x0302,
541 WM_CLEAR = 0x0303,
542 WM_UNDO = 0x0304,
543 WM_RENDERFORMAT = 0x0305,
544 WM_RENDERALLFORMATS = 0x0306,
545 WM_DESTROYCLIPBOARD = 0x0307,
546 WM_DRAWCLIPBOARD = 0x0308,
547 WM_PAINTCLIPBOARD = 0x0309,
548 WM_VSCROLLCLIPBOARD = 0x030A,
549 WM_SIZECLIPBOARD = 0x030B,
550 WM_ASKCBFORMATNAME = 0x030C,
551 WM_CHANGECBCHAIN = 0x030D,
552 WM_HSCROLLCLIPBOARD = 0x030E,
553 WM_QUERYNEWPALETTE = 0x030F,
554 WM_PALETTEISCHANGING = 0x0310,
555 WM_PALETTECHANGED = 0x0311,
556 WM_HOTKEY = 0x0312,
557 WM_PRINT = 0x0317,
558 WM_PRINTCLIENT = 0x0318,
559 WM_THEME_CHANGED = 0x031A,
560 WM_HANDHELDFIRST = 0x0358,
561 WM_HANDHELDLAST = 0x035F,
562 WM_AFXFIRST = 0x0360,
563 WM_AFXLAST = 0x037F,
564 WM_PENWINFIRST = 0x0380,
565 WM_PENWINLAST = 0x038F,
566 WM_APP = 0x8000,
567 WM_USER = 0x0400,
568 WM_REFLECT = WM_USER + 0x1c00
569 }
570 #endregion
571
572 #region SetWindowPosFlags
573 public enum SetWindowPosFlags
574 {
575 SWP_NOSIZE = 0x0001,
576 SWP_NOMOVE = 0x0002,
577 SWP_NOZORDER = 0x0004,
578 SWP_NOREDRAW = 0x0008,
579 SWP_NOACTIVATE = 0x0010,
580 SWP_FRAMECHANGED = 0x0020,
581 SWP_SHOWWINDOW = 0x0040,
582 SWP_HIDEWINDOW = 0x0080,
583 SWP_NOCOPYBITS = 0x0100,
584 SWP_NOOWNERZORDER = 0x0200,
585 SWP_NOSENDCHANGING = 0x0400,
586 SWP_DRAWFRAME = 0x0020,
587 SWP_NOREPOSITION = 0x0200,
588 SWP_DEFERERASE = 0x2000,
589 SWP_ASYNCWINDOWPOS = 0x4000
590 }
591 #endregion
592 }
593
594 #region WINDOWINFO
595 [StructLayout(LayoutKind.Sequential)]
596 public struct WINDOWINFO
597 {
598 public UInt32 cbSize;
599 public RECT rcWindow;
600 public RECT rcClient;
601 public UInt32 dwStyle;
602 public UInt32 dwExStyle;
603 public UInt32 dwWindowStatus;
604 public UInt32 cxWindowBorders;
605 public UInt32 cyWindowBorders;
606 public UInt16 atomWindowType;
607 public UInt16 wCreatorVersion;
608 }
609 #endregion
610
611 #region POINT
612 [StructLayout(LayoutKind.Sequential)]
613 public struct POINT
614 {
615 public int x;
616 public int y;
617
618 #region Constructors
619 public POINT(int x, int y)
620 {
621 this.x = x;
622 this.y = y;
623 }
624
625 public POINT(Point point)
626 {
627 x = point.X;
628 y = point.Y;
629 }
630 #endregion
631 }
632 #endregion
633
634 #region RECT
635 [StructLayout(LayoutKind.Sequential)]
636 public struct RECT
637 {
638 public uint left;
639 public uint top;
640 public uint right;
641 public uint bottom;
642
643 #region Properties
644 public POINT Location
645 {
646 get { return new POINT((int)left, (int)top); }
647 set
648 {
649 right -= (left - (uint)value.x);
650 bottom -= (bottom - (uint)value.y);
651 left = (uint)value.x;
652 top = (uint)value.y;
653 }
654 }
655
656 public uint Width
657 {
658 get { return right - left; }
659 set { right = left + value; }
660 }
661
662 public uint Height
663 {
664 get { return bottom - top; }
665 set { bottom = top + value; }
666 }
667 #endregion
668
669 #region Overrides
670 public override string ToString()
671 {
672 return left + ":" + top + ":" + right + ":" + bottom;
673 }
674 #endregion
675 }
676 #endregion
677
678 #region WINDOWPOS
679 [StructLayout(LayoutKind.Sequential)]
680 public struct WINDOWPOS
681 {
682 public IntPtr hwnd;
683 public IntPtr hwndAfter;
684 public int x;
685 public int y;
686 public int cx;
687 public int cy;
688 public uint flags;
689
690 #region Overrides
691 public override string ToString()
692 {
693 return x + ":" + y + ":" + cx + ":" + cy + ":" + ((SWP_Flags)flags).ToString();
694 }
695 #endregion
696 }
697 #endregion
698
699 #region NCCALCSIZE_PARAMS
700 [StructLayout(LayoutKind.Sequential)]
701 public struct NCCALCSIZE_PARAMS
702 {
703 public RECT rgrc1;
704 public RECT rgrc2;
705 public RECT rgrc3;
706 public IntPtr lppos;
707 }
708 #endregion
709
710 #region NMHDR
711 [StructLayout(LayoutKind.Sequential)]
712 public struct NMHDR
713 {
714 public IntPtr hwndFrom;
715 public uint idFrom;
716 public uint code;
717 }
718 #endregion
719
720 #region OFNOTIFY
721 [StructLayout(LayoutKind.Sequential)]
722 public struct OFNOTIFY
723 {
724 public NMHDR hdr;
725 public IntPtr OPENFILENAME;
726 public IntPtr fileNameShareViolation;
727 }
728 #endregion
补充一下
1.代码只提供思路，不能拿来继承一下，就能实现自己想要的功能。
2.可以自己将代码中DialogNativeWindow类的addControl替换为其他控件，比如PictureBox用来预览图片、TextBox用来预览txt文件、RichTextBox用来预览代码文件等等，还可自由组合。
3.可以自己将代码中DialogNativeWindow类的两个事件（SelectedFileChanged、SelectPathChanged）移到MultiOpenFileDialog中，并使其对外开放，外部程序可以监听该事件。
4.如果想做成通用类，拿过来继承一下就可以实现自己想要的效果，建议使MultiOpenFileDialog从UserControl，并将addControl设为自己。也就是说将自己添加到OpenFileDialog中去，MultiOpenFileDialog的派生类就可以在VS中设计自己想要的效果。
5.一个窗体新建显示时，它的拥有者会接收许多消息，包括WM_ACTIVATE、WM_IDLE等等，并且Lparam参数为新建窗体的句柄。
View Code
1 class Form1:Form
2 {
3 private void Form1_Load(Object sender,EventArgs e)
4 {
5 using(OpenFileDialog dia = new OpenFileDialog())
6 {
7 dia.ShowDialog(this);
8 }
9 }
10 protected override void WndProc(ref Message m)
11 {
12 //当dia显示时，它的拥有者即为this，这里会接受一连串的Window消息，并且它的Lparam参数为dia的句柄
13 base.WndProc(ref m);
14 }
15 }
6.Windows中窗体和所谓的控件（button、textbox）本质上没有区别，任务栏与QQ聊天框或者Chrome浏览器的地址栏对我们程序员来讲，是同一个东西。
7.与窗体有关的Win32 API基本都需要窗体句柄，其实任何一个API几乎都需要知道操作对象的句柄（不一定是窗体）。
8.Windows中任何一个窗体（控件）理论上都是平级的，不管是否同一进程，也就是说，我的winform应用程序只要知道了Chrome浏览器窗体的句柄，就可以控制Chrome浏览器，监听Chrome窗体的Windows消息（除非Chrome程序本身禁止了此操作）。
9.Windows桌面应用程序开发中，（部分平台、语言）理解四个东西，即进程、线程 、窗体（已经说了，是广义上的窗体）、消息。
10.查看系统中以上四个东西，可以使用Spy++工具。
完了，剩下那个下次再写了，太多了。希望有帮助~
