BrightIdeasSoftware.ObjectListView.LowLevelHitTest C# (CSharp) Method

        protected OlvListViewHitTestInfo LowLevelHitTest(int x, int y)
        {
            // If it's not even in the control, don't bother with anything else
            if (!this.ClientRectangle.Contains(x, y))
                return new OlvListViewHitTestInfo(null, null, 0, null);

            //if (Control.ModifierKeys == Keys.Control)
            //    System.Diagnostics.Debugger.Break();

            // Call the native hit test method, which is a little confusing.
            NativeMethods.LVHITTESTINFO lParam = new NativeMethods.LVHITTESTINFO();
            lParam.pt_x = x;
            lParam.pt_y = y;
            int index = NativeMethods.HitTest(this, ref lParam);

            // Setup the various values we need to make our hit test structure
            bool isGroupHit = (lParam.flags & (int)HitTestLocationEx.LVHT_EX_GROUP) != 0;
            OLVListItem hitItem = isGroupHit || index == -1 ? null : this.GetItem(index);
            OLVListSubItem subItem = (this.View == View.Details && hitItem != null) ? hitItem.GetSubItem(lParam.iSubItem) : null;

            // Figure out which group is involved in the hit test. This is a little complicated:
            // If the list is virtual:
            //   - the returned value is list view item index
            //   - iGroup is the *index* of the hit group.
            // If the list is not virtual:
            //   - iGroup is always -1.
            //   - if the point is over a group, the returned value is the *id* of the hit group.
            //   - if the point is not over a group, the returned value is list view item index.
            OLVGroup group = null;
            if (this.ShowGroups && this.OLVGroups != null) {
                if (this.VirtualMode) {
                    group = lParam.iGroup >= 0 && lParam.iGroup < this.OLVGroups.Count ? this.OLVGroups[lParam.iGroup] : null;
                } else {
                    if (isGroupHit) {
                        foreach (OLVGroup olvGroup in this.OLVGroups) {
                            if (olvGroup.GroupId == index) {
                                group = olvGroup;
                                break;
                            }
                        }
                    }
                }
            }
            OlvListViewHitTestInfo olvListViewHitTest = new OlvListViewHitTestInfo(hitItem, subItem, lParam.flags, group);
            // System.Diagnostics.Debug.WriteLine(String.Format("HitTest({0}, {1})=>{2}", x, y, olvListViewHitTest));
            return olvListViewHitTest;
        }