listviewextender.cs

基于ehotgis嵌入式gis平台的图层控制源码

using System;
using System.Drawing;
using System.Collections;
using System.Windows.Forms;
using System.Runtime.InteropServices;


namespace ListViewToolTip
{
	/// <summary>
	/// Summary description for ListViewExtender.
	/// </summary>
	public class ListViewExtender
	{
		protected ListView listView;
		protected IntPtr handle;

		public ListViewExtender(ListView listView)
		{
			this.listView = listView;
			this.listView.Capture = true;
			this.handle = this.listView.Handle;
			this.listView.Capture = false;
		}


		public HitItem GetItemAt(int x, int y)
		{
			HitItem hitItem = new HitItem();

			// Init LVHITTESTINFO structure
			LVHITTESTINFO hitTextInfo = new LVHITTESTINFO();
			hitTextInfo.x = x;
			hitTextInfo.y = y;
			hitTextInfo.flags = LVHT_ONITEM;
			
			// Allocate native memory
			IntPtr pointer = AllocHGlobal(Marshal.SizeOf(hitTextInfo));
			// Copy LVHITTESTINFO structure to the memory pointer
			Marshal.StructureToPtr(hitTextInfo, pointer, false);
			
			// Retreive item/subitem indexes
			SendMessage(handle, LVM_SUBITEMHITTEST, 0, pointer);

			hitTextInfo = (LVHITTESTINFO)Marshal.PtrToStructure(pointer, typeof(LVHITTESTINFO));
			FreeHGlobal(pointer);

			hitItem.ItemIndex = hitTextInfo.iItem;
			hitItem.SubItemIndex = hitTextInfo.iSubItem;
			
			return hitItem;

		}

		public Rectangle GetItemRectangle(int itemIndex, int subItemIndex)
		{
			RECT rect = new RECT();
			rect.left = 2;
			rect.top = subItemIndex;
			// Retreive item's rectangle
			SendMessage(handle, LVM_GETSUBITEMRECT, itemIndex, ref rect);
			// Convert to the screen coordinates
			Rectangle rc = listView.RectangleToScreen(new Rectangle(rect.left, rect.top - 26, rect.right - rect.left, rect.bottom - rect.top));
			return rc;
		}

		private static IntPtr AllocHGlobal(int cb)
		{
			IntPtr ptr = LocalAlloc(LPTR, (uint)cb);
			if (ptr == IntPtr.Zero)
			{
				throw new OutOfMemoryException();

			}
			return ptr;
		}


		private static void FreeHGlobal(IntPtr hGlobal)
		{
			if (hGlobal != IntPtr.Zero)
				LocalFree(hGlobal);
		}

		#region P/Invokes

		private const int GMEM_FIXED = 0x0000;
		private const int LMEM_MOVEABLE = 2;
		private const int LMEM_ZEROINIT = 0x0040;
		private const int LPTR = (GMEM_FIXED | LMEM_ZEROINIT);

		[DllImport("coredll.dll", EntryPoint = "LocalAlloc", SetLastError = true)]
		static extern IntPtr LocalAlloc(uint uFlags, uint Bytes);

		[DllImport("coredll.dll", EntryPoint = "LocalReAlloc", SetLastError = true)]
		static extern IntPtr LocalReAllocCE(IntPtr hMem, int uBytes, int fuFlags);

		[DllImport("coredll.dll", EntryPoint = "LocalFree", SetLastError = true)]
		static extern IntPtr LocalFree(IntPtr hMem);

		[DllImport("coredll.dll")] 
		static extern IntPtr GetCapture(); 

		[DllImport("coredll.dll", SetLastError = true)]
		static extern int SendMessage(IntPtr hwnd, int msg, int wParam, ref LVHITTESTINFO rect);

		[DllImport("coredll.dll", SetLastError = true)]
		static extern int SendMessage(IntPtr hwnd, int msg, int wParam, IntPtr lParam);

		[DllImport("coredll.dll", SetLastError=true)]
		static extern int SendMessage(IntPtr hwnd, int msg, int wParam, ref RECT rect);

		const int LVM_FIRST = 0x1000;
		const int LVM_GETITEMRECT = (LVM_FIRST + 14);
		const int LVM_HITTEST = (LVM_FIRST + 18);
		const int LVM_GETSUBITEMRECT = (LVM_FIRST + 56);
		const int LVM_SUBITEMHITTEST = (LVM_FIRST + 57); 


		const int LVHT_NOWHERE    =        0x0001;
		const int LVHT_ONITEMICON         =0x0002;
		const int LVHT_ONITEMLABEL       = 0x0004;
		const int LVHT_ONITEMSTATEICON   = 0x0008;
		const int LVHT_ONITEM = (LVHT_ONITEMICON | LVHT_ONITEMLABEL | LVHT_ONITEMSTATEICON);


		public struct RECT
		{
			public int left;
			public int top;
			public int right;
			public int bottom;
		}

		private struct POINT
		{
			public int x;
			public int y;
		}

		private struct LVHITTESTINFO 
		{
			//public POINT point;
			public int x; 
			public int y;
			public int flags;
			public int iItem;
			public int iSubItem;
		}

		#endregion

		public struct HitItem
		{
			public int ItemIndex;
			public int SubItemIndex;
		}

	}
}