This is more difficult than one might think. In order to get the information you're looking for, you have to execute the code in the same process space as the application containing the ListView control. You do that by allocating a block of memory in the target process that is large enough to hold the LVITEM structure and the string data you expect to be returned, then move that structure to the target process. The .NET Framework makes things quite a bit easier on us here with the Marshal class.
Once you've taken that into account, it's a simple matter of declaring the LVITEM structure and sending the LVM_GETITEM message to the control using the SendMessage function, as you suspected.
// P/Invoke declarationsprivateconstint LVM_FIRST =0x1000;privateconstint LVM_GETITEMCOUNT = LVM_FIRST +4;privateconstint LVM_GETITEM = LVM_FIRST +75;privateconstint LVIF_TEXT =0x0001;[DllImport("user32.dll"),CharSet=CharSet.Auto]privatestaticexternIntPtrSendMessage(IntPtr hWnd,intMsg,IntPtr wParam,IntPtr lParam);[StructLayoutAttribute(LayoutKind.Sequential)]privatestruct LVITEM
{publicuint mask;publicint iItem;publicint iSubItem;publicuint state;publicuint stateMask;publicIntPtr pszText;publicint cchTextMax;publicint iImage;publicIntPtr lParam;}And then you would use it like this (assuming hListView is a valid handle to a ListView control):
// Declare and populate the LVITEM structure
LVITEM lvi =new LVITEM();
lvi.mask = LVIF_TEXT;
lvi.cchTextMax =512;
lvi.iItem =1;// the zero-based index of the ListView item
lvi.iSubItem =0;// the one-based index of the subitem, or 0 if this// structure refers to an item rather than a subitem
lvi.pszText =Marshal.AllocHGlobal(512);// Send the LVM_GETITEM message to fill the LVITEM structureIntPtr ptrLvi =Marshal.AllocHGlobal(Marshal.SizeOf(lvi));Marshal.StructureToPtr(lvi, ptrLvi,false);SendMessage(hListView, LVM_GETITEM,IntPtr.Zero, ptrLvi);// Extract the text of the specified itemstring itemText =Marshal.PtrToStringAuto(lvi.pszText);