C#拖放问题
本文关键字:问题 拖放 | 更新日期: 2023-09-27 17:52:12
我有一个C#.NET 3.5应用程序,它允许从树中拖动项目,并将它们作为文件放到文件夹中。这是我的代码
String absolutePathToFile=...get absolute path
DataObject dataObject = new DataObject();
StringCollection paths = new StringCollection();
paths.Add(absolutePathToFile);
dataObject.SetFileDropList(paths);
DoDragDrop(dataObject, DragDropEffects.Copy);
除了与另一个通过拖放接受文件的C#应用程序交互时,这一操作效果很好。另一个C#应用程序具有以下DragOver 处理程序
if ((e.Data is DataObject) && (e.Data as DataObject).ContainsFileDropList())
{
e.Effect = DragDropEffects.Copy;
}
由于e.数据是__ComObject而不是DataObject,因此从未执行该块。有趣的是,当我把一个文件从文件夹拖到第二个应用程序上时,它会把它看作DataObject。
如何使第一个C#应用程序中的DataObject在第二个C#应用中显示为DataObject?
我决定从IDataObjec
t实现开始,使用.NET Interop实现IDataObject
。然后定义了DROPFILES
结构
[StructLayoutAttribute(LayoutKind.Sequential)]
internal struct _DROPFILES
{
public Int32 pFiles;
public Int32 X;
public Int32 Y;
public bool fNC;
public bool fWide;
}
并实现填充所有OLE结构的代码。下面的函数返回我在DoDragDrop:中使用的IDataObject
DoDragDrop(GetDataObject(new String[] { file name }), DragDropEffects.Copy);
DataObject2 GetDataObject(String[] strFiles)
{
byte[] bData;
_DROPFILES df = new _DROPFILES();
int intChar, intFile, intDataLen, intPos;
IntPtr ipGlobal = IntPtr.Zero;
// Calculate total data length
intDataLen = 0;
for (intFile = 0; intFile <= strFiles.GetUpperBound(0);intFile++)
{
intDataLen += strFiles[intFile].Length + 1;
}
// Terminating double zero
intDataLen++;
bData = new Byte[intDataLen];
intPos = 0;
// Build null terminated list of files
for (intFile = 0; intFile <= strFiles.GetUpperBound(0); intFile++)
{
for (intChar = 0; intChar < strFiles[intFile].Length;intChar++)
{
bData[intPos++] = (byte)strFiles[intFile][intChar];
}
bData[intPos++] = 0;
}
// Terminating double zero
bData[intPos++] = 0;
// Allocate and get pointer to global memory
int intTotalLen = Marshal.SizeOf(df) + intDataLen;
ipGlobal = Marshal.AllocHGlobal(intTotalLen);
if (ipGlobal == IntPtr.Zero)
{
return null;
}
// Build DROPFILES structure in global memory.
df.pFiles = Marshal.SizeOf(df);
df.fWide = false;
Marshal.StructureToPtr(df, ipGlobal, true);
IntPtr ipNew = new IntPtr(ipGlobal.ToInt32() + Marshal.SizeOf(df));
Marshal.Copy(bData, 0, ipNew, intDataLen);
short CF_HDROP = 15;
System.Runtime.InteropServices.ComTypes.FORMATETC formatEtc;
System.Runtime.InteropServices.ComTypes.STGMEDIUM stgMedium;
formatEtc = new System.Runtime.InteropServices.ComTypes.FORMATETC();
formatEtc.cfFormat = CF_HDROP;
formatEtc.dwAspect = System.Runtime.InteropServices.ComTypes.DVASPECT.DVASPECT_CONTENT;
formatEtc.lindex = -1;
formatEtc.tymed = System.Runtime.InteropServices.ComTypes.TYMED.TYMED_HGLOBAL;
stgMedium = new System.Runtime.InteropServices.ComTypes.STGMEDIUM();
stgMedium.unionmember = ipGlobal;
stgMedium.tymed = System.Runtime.InteropServices.ComTypes.TYMED.TYMED_HGLOBAL;
DataObject2 dobj = new DataObject2();
dobj.SetData(ref formatEtc, ref stgMedium, false);
return dobj;
}
有了新代码,第二个应用程序在e.Data
中看到DataObject
,我可以将该文件拖放到任何应用程序。只是现在资源管理器不接受文件。我的实现中是否遗漏了什么?