7
我想將一個listbox的元素拖放到資源管理器中。當拖放開始時,我需要按需準備文件並將其保存到內存流中。 你能否提供一個關於如何使用FileGroupDescriptor數據結構來實現的例子? 謝謝。 Andrea如何使用filegroupdescriptor將文件拖到資源管理器c#
我想將一個listbox的元素拖放到資源管理器中。當拖放開始時,我需要按需準備文件並將其保存到內存流中。 你能否提供一個關於如何使用FileGroupDescriptor數據結構來實現的例子? 謝謝。 Andrea如何使用filegroupdescriptor將文件拖到資源管理器c#
你可以在這裏找到一個關於如何做到這一點的例子Transferring Virtual Files to Windows Explorer in C#;關於這個主題的一些很好的信息在這裏:Outlook Drag and Drop in C#
總之你要做的就是用FILEDESCRIPTOR初始化DataObject(你可以在pinvoke.net上找到它的聲明細節)文件獲取的結構(s)轉移和他們的內容。下面是如何將文件從winforms ListBox轉移到資源管理器的示例。
鼠標按下事件處理程序列表框:給init數據對象需要
private void listBox1_MouseDown(object sender, MouseEventArgs e)
{
DataObject dataObject = new DataObject();
DragFileInfo filesInfo = new DragFileInfo("d:\\test.txt");
using (MemoryStream infoStream = GetFileDescriptor(filesInfo),
contentStream = GetFileContents(filesInfo))
{
dataObject.SetData(CFSTR_FILEDESCRIPTORW, infoStream);
dataObject.SetData(CFSTR_FILECONTENTS, contentStream);
dataObject.SetData(CFSTR_PERFORMEDDROPEFFECT, null);
DoDragDrop(dataObject, DragDropEffects.All);
}
}
代碼:
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
struct FILEDESCRIPTOR
{
public UInt32 dwFlags;
public Guid clsid;
public System.Drawing.Size sizel;
public System.Drawing.Point pointl;
public UInt32 dwFileAttributes;
public System.Runtime.InteropServices.ComTypes.FILETIME ftCreationTime;
public System.Runtime.InteropServices.ComTypes.FILETIME ftLastAccessTime;
public System.Runtime.InteropServices.ComTypes.FILETIME ftLastWriteTime;
public UInt32 nFileSizeHigh;
public UInt32 nFileSizeLow;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=260)]
public String cFileName;
}
public const string CFSTR_PREFERREDDROPEFFECT = "Preferred DropEffect";
public const string CFSTR_PERFORMEDDROPEFFECT = "Performed DropEffect";
public const string CFSTR_FILEDESCRIPTORW = "FileGroupDescriptorW";
public const string CFSTR_FILECONTENTS = "FileContents";
public const Int32 FD_WRITESTIME = 0x00000020;
public const Int32 FD_FILESIZE = 0x00000040;
public const Int32 FD_PROGRESSUI = 0x00004000;
public struct DragFileInfo
{
public string FileName;
public string SourceFileName;
public DateTime WriteTime;
public Int64 FileSize;
public DragFileInfo(string fileName)
{
FileName = Path.GetFileName(fileName);
SourceFileName = fileName;
WriteTime = DateTime.Now;
FileSize = (new FileInfo(fileName)).Length;
}
}
private MemoryStream GetFileDescriptor(DragFileInfo fileInfo)
{
MemoryStream stream = new MemoryStream();
stream.Write(BitConverter.GetBytes(1), 0, sizeof(UInt32));
FILEDESCRIPTOR fileDescriptor = new FILEDESCRIPTOR();
fileDescriptor.cFileName = fileInfo.FileName;
Int64 fileWriteTimeUtc = fileInfo.WriteTime.ToFileTimeUtc();
fileDescriptor.ftLastWriteTime.dwHighDateTime = (Int32)(fileWriteTimeUtc >> 32);
fileDescriptor.ftLastWriteTime.dwLowDateTime = (Int32)(fileWriteTimeUtc & 0xFFFFFFFF);
fileDescriptor.nFileSizeHigh = (UInt32)(fileInfo.FileSize >> 32);
fileDescriptor.nFileSizeLow = (UInt32)(fileInfo.FileSize & 0xFFFFFFFF);
fileDescriptor.dwFlags = FD_WRITESTIME | FD_FILESIZE | FD_PROGRESSUI;
Int32 fileDescriptorSize = Marshal.SizeOf(fileDescriptor);
IntPtr fileDescriptorPointer = Marshal.AllocHGlobal(fileDescriptorSize);
Byte[] fileDescriptorByteArray = new Byte[fileDescriptorSize];
try
{
Marshal.StructureToPtr(fileDescriptor, fileDescriptorPointer, true);
Marshal.Copy(fileDescriptorPointer, fileDescriptorByteArray, 0, fileDescriptorSize);
}
finally
{
Marshal.FreeHGlobal(fileDescriptorPointer);
}
stream.Write(fileDescriptorByteArray, 0, fileDescriptorByteArray.Length);
return stream;
}
private MemoryStream GetFileContents(DragFileInfo fileInfo)
{
MemoryStream stream = new MemoryStream();
using (BinaryReader reader = new BinaryReader(File.OpenRead(fileInfo.SourceFileName)))
{
Byte[] buffer = new Byte[fileInfo.FileSize];
reader.Read(buffer, 0, (Int32)fileInfo.FileSize);
if (buffer.Length == 0) buffer = new Byte[1];
stream.Write(buffer, 0, buffer.Length);
}
return stream;
}
希望這會給你如何進行的一個想法, 問候
我在C++上真的很差,但是這樣做是否與本文中討論的使用了錯誤的'sizeof()'運算符相同? http://www.codeproject.com/KB/cs/UnmanagedArraysInCSharp.aspx 他們說'Marshal.SizeOf'給出了編組後的大小。 – Maslow 2010-06-22 13:03:27