自定义FileDialog的外观

在.NET里面，MS提供了OpenFileDialog和SaveFileDialog，但是MS暴露给我们的方法和属性很少。有的时候我们需要修改他们的外观，比如修改默认的显示风格，默认的排序，甚至要求在Dialog中浏览图片等。这个时候我们除了重做一个Dialog那么就只能依靠消息来达到我们的目的。

关于如果在Dialog中浏览图片的文章，大家可以参考下CodeProject上的http://www.codeproject.com/KB/dialog/OpenFileDialogEx.aspx 这篇文章。

那么如何来改变默认的显示方式，以及如果是Details形式的话，如何更改默认的排序属性呢，这个就是我这篇文章需要介绍的内容。

 

我先说一下大致的思路：

我们用Spy++看到，点击列排序的时候是LVM_SORTITEMS消息

通过MSDN我们知道，发送LVM_SORTITEMS需要同时提供排序的方法，因此要把你排序的方法放到SendMessage的参数中
在排序的方法中通过LVM_FINDITEM和LVM_GETITEMTEXT等消息获得需要排序的列
然后比较并且返回比较结果

MSDN里面有个例子，大家可以参考下： http://support.microsoft.com/kb/170884/

 

好了，接下来就说下我实现的方式吧，我这次主要是实现对日期列的排序，如果大家需要用到其他的列的话，请注意修改排序的代码

  首先，我们需要定义两个enum，一个是用来表示默认的显示类型，一个是表示排序类型，具体代码如下

 

public enum FileListView{ Icons = 0x7029, SmallIcons = 0x702a, List = 0x702b, Details = 0x702c, Thumbnails = 0x7031, XpThumbnails = 0x702d}public enum DialogOrderType{ Ascending, Descending}

 

 

然后需要定义一些消息常量以及结构，这个没什么说的了，都是通过MSDN查到的

 

[StructLayout(LayoutKind.Sequential)]private struct LV_FINDINFO{ public int flags; public string psz; public int lParam; public POINT pt; public int vkDirection;}[StructLayout(LayoutKind.Sequential)]private struct LV_ITEM{ public int mask; public int iItem; public int iSubItem; public int state; public int stateMask; public string pszText; public int cchTextMax; public int iImage; public int lParam; public int iIndent;}[StructLayout(LayoutKind.Sequential)]private struct NMHDR{ public int hwndFrom; public int idFrom; public int code;}[StructLayout(LayoutKind.Sequential)]private struct POINT{ public int x; public int y;}[StructLayout(LayoutKind.Sequential)]private struct NM_LISTVIEW{ public NMHDR hdr; public int iItem; public int iSubItem; public int uNewState; public int uOldState; public int uChanged; public POINT ptAction; public int lParam;}[StructLayout(LayoutKind.Sequential)]private struct HDITEM{ public int mask; public int cxy; public string pszText; public int hbm; public int cchTextMax; public int fmt; public int lParam; public int iImage; public int iOrder;}public const int WM_COMMAND = 0x0111;public const int WM_ENTERIDLE = 0x0121;public const int LVFI_PARAM = 0x1;public const int LVIF_TEXT = 0x1;public const int LVM_FIRST = 0x1000;public const int LVM_FINDITEM = (LVM_FIRST + 13);public const int LVM_GETITEMTEXT = (LVM_FIRST + 45);public const int LVM_SORTITEMS = (LVM_FIRST + 48);public const int LVM_GETHEADER = (LVM_FIRST + 31);public const int LVM_SETSELECTEDCOLUMN = LVM_FIRST + 140;public const int HDI_FORMAT = 0x4;public const int HDF_LEFT = 0;public const int HDF_STRING = 0x4000;public const int HDF_SORTUP = 0x400;public const int HDF_SORTDOWN = 0x200;public const int HDM_FIRST = 0x1200;public const int HDM_SETITEM = HDM_FIRST + 12;public const int HDM_GETITEM = HDM_FIRST + 11;

 

接下来就是API的引用，这里主要用到SendMessage和FindWindowEx

[DllImport("user32.dll", EntryPoint = "SendMessageA", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]private static extern int SendMessage(int Hdc, int Msg_Const, int wParam, ref HDITEM lParam);[DllImport("user32.dll", EntryPoint = "SendMessageA", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]private static extern int SendMessage(int Hdc, int Msg_Const, int wParam, int lParam);[DllImport("user32.dll", EntryPoint = "SendMessageA", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]private static extern int SendMessage(int Hdc, int Msg_Const, int wParam, ref LV_FINDINFO lParam);[DllImport("user32.dll", EntryPoint = "SendMessageA", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]private static extern int SendMessage(int Hdc, int Msg_Const, int wParam, ref LV_ITEM lParam);[DllImport("user32.dll", EntryPoint="FindWindowExA", CallingConvention=CallingConvention.StdCall,CharSet=CharSet.Ansi)]private static extern int FindWindowEx(int hwndParent, int hwndChildAfter, string lpszClass, string lpszWindow);

 

 

上面这些代码我建议大家专门放到一个类里面，以后用到的所有的API方面的东西都可以从这个类里面获得

 

以下就是FileDialogExtender类的内容，这个类继承自我的HookWndProc类，

这个类的代码在以前写的那篇NativeWindow的文章，建议大家先去看看

http://blog.csdn.net/lovefootball/archive/2007/09/14/1784882.aspx

 

 public class FileDialogExtender : HookWndProc{ //排序用的委托 private delegate int CompareDatesDelegate(int lParam1, int lParam2, int wnd); private ApiHelp.LV_FINDINFO lvFindInfo = new ApiHelp.LV_FINDINFO(); private ApiHelp.LV_ITEM lvItem = new ApiHelp.LV_ITEM(); private int lastListViewHandle = 0; //日期数据的排序方法 private int CompareDates(int lParam1, int lParam2, int wnd) { bool order = (OrderType == DialogOrderType.Descending); DateTime dDate1; DateTime dDate2; string temp1 = GetItemDate(wnd, lParam1); string temp2 = GetItemDate(wnd, lParam2); if (temp1.IndexOf("@") >= 0 && temp2.IndexOf("@") >= 0) { dDate1 = Convert.ToDateTime(temp1.Substring(1)); dDate2 = Convert.ToDateTime(temp2.Substring(1)); } else if (temp1.IndexOf("@") >= 0 && temp2.IndexOf("@") < 0) { dDate1 = DateTime.MinValue; dDate2 = Convert.ToDateTime(temp2); } else if (temp1.IndexOf("@") < 0 && temp2.IndexOf("@") >= 0) { dDate1 = Convert.ToDateTime(temp1); dDate2 = DateTime.MinValue; } else { dDate1 = Convert.ToDateTime(temp1); dDate2 = Convert.ToDateTime(temp2); } if (order) { if (dDate1 < dDate2) { return 2; } else if (dDate1 == dDate2) { return 1; } else { return 0; } } else { if (dDate1 > dDate2) { return 2; } else if (dDate1 == dDate2) { return 1; } else { return 0; } } } //获得日期列的数据 private string GetItemDate(int wnd, int lParam) { lvFindInfo.flags = ApiHelp.LVFI_PARAM; lvFindInfo.lParam = lParam; int index = ApiHelp.SendMessage(wnd, ApiHelp.LVM_FINDITEM, -1, ref lvFindInfo); lvItem.mask = ApiHelp.LVIF_TEXT; lvItem.iSubItem = 3; lvItem.pszText = " "; lvItem.cchTextMax = 32; int result = ApiHelp.SendMessage(wnd, ApiHelp.LVM_GETITEMTEXT, index, ref lvItem); if (result > 0) { //由于Dialog的排序时区分文件和文件夹，所以自己写排序的时候也要区分一下， //这里我偷懒了，直接用大小这个列来判断是文件还是文件夹，如果大小为“”，则为文件夹 string size = GetItemSize(wnd, lParam); if (String.IsNullOrEmpty(size)) { return "@" + lvItem.pszText.ToString(); } return lvItem.pszText.ToString(); } return ""; } //获得大小列的数据 private string GetItemSize(int wnd, int lParam) { ApiHelp.LV_FINDINFO find = new ApiHelp.LV_FINDINFO(); find.flags = ApiHelp.LVFI_PARAM; find.lParam = lParam; int index = ApiHelp.SendMessage(wnd, ApiHelp.LVM_FINDITEM, -1, ref find); ApiHelp.LV_ITEM item = new ApiHelp.LV_ITEM(); item.mask = ApiHelp.LVIF_TEXT; item.iSubItem = 1; item.pszText = " "; item.cchTextMax = 32; int result = ApiHelp.SendMessage(wnd, ApiHelp.LVM_GETITEMTEXT, index, ref item); if (result > 0) { return item.pszText.Trim(); } return ""; } private FileListView view = FileListView.Details; public FileListView View { get { return view; } set { view = value; } } private DialogOrderType orderType = DialogOrderType.Descending; public DialogOrderType OrderType { get { return orderType; } set { orderType = value; } } protected override void WndProc(ref Message m) { if (m.Msg == ApiHelp.WM_ENTERIDLE) { if (lastListViewHandle == 0) { int dialogHandle = m.LParam.ToInt32(); int listviewHandle = ApiHelp.FindWindowEx(dialogHandle, 0, "SHELLDLL_DefView", ""); if (listviewHandle != 0) { //默认显示Details ApiHelp.SendMessage(listviewHandle, ApiHelp.WM_COMMAND, (int)View, 0); } if (View == FileListView.Details) { int listHandle = ApiHelp.FindWindowEx(listviewHandle, 0, "SysListView32", "FolderView"); if (listHandle != 0) { //得到Header int hHeader = ApiHelp.SendMessage(listHandle, ApiHelp.LVM_GETHEADER, 0, 0); //去掉名称列的图标 ApiHelp.HDITEM hdName = new ApiHelp.HDITEM(); hdName.mask = ApiHelp.HDI_FORMAT; ApiHelp.SendMessage(hHeader, ApiHelp.HDM_GETITEM, 0, ref hdName); hdName.fmt ^= ApiHelp.HDF_SORTUP; ApiHelp.SendMessage(hHeader, ApiHelp.HDM_SETITEM, 0, ref hdName); //设置日期列为排序列，并且根据排序种类设置排序顺序 ApiHelp.HDITEM hd = new ApiHelp.HDITEM(); hd.mask = ApiHelp.HDI_FORMAT; hd.fmt = ApiHelp.HDF_LEFT | ApiHelp.HDF_STRING; if (OrderType == DialogOrderType.Descending) { hd.fmt |= ApiHelp.HDF_SORTDOWN; } else { hd.fmt |= ApiHelp.HDF_SORTUP; } ApiHelp.SendMessage(hHeader, ApiHelp.HDM_SETITEM, 3, ref hd); ApiHelp.SendMessage(listHandle, ApiHelp.LVM_SORTITEMS, listHandle, Marshal.GetFunctionPointerForDelegate(new CompareDatesDelegate(CompareDates)).ToInt32()); //设置日期列为最后的选择列 ApiHelp.SendMessage(listHandle, ApiHelp.LVM_SETSELECTEDCOLUMN, 3, 0); } } lastListViewHandle = listviewHandle; } } this.FireWndProcEvent(ref m); }}

 

 

调用的方法如下：

 

 FileDialogExtender fd = new FileDialogExtender();OpenFileDialog of = new OpenFileDialog();fd.BeginHookProc(this);fd.View = FileListView.Details;of.ShowDialog();fd.EndHookProc(this);

 

 

恩，大致的功能就实现了

 

大家需要注意的是设置完默认显示为Details格式的时候，他默认的是名称排序，

这个时候我们不仅要去掉名称列上的三角图标，还要改成其他列排序，

而且还需要发送LVM_SETSELECTEDCOLUMN消息，告诉对话框，我们选择的是哪个列

 

大家如果有兴趣的话，可以参照这个例子进行扩展

首先列的排序应该是做成属性，在外面调用的时候配置的

另外Details形式下还可以默认显示成其他的列，而不是对话框给我们的四个列

或者可以改变列的顺序，把日期弄到第一列等等

 

 

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