bool IDropTarget.CanDropElement(UIElement draggedElement)
{
ColumnManagerCell cell = null;
HierarchicalGroupByItem hierarchicalGroupByItem = null;
bool canDrop = this.AllowGroupingModification;
if (canDrop)
{
cell = draggedElement as ColumnManagerCell;
if (cell != null)
{
ColumnBase parentColumn = cell.ParentColumn;
if ((parentColumn == null) || (!parentColumn.AllowGroup))
{
return(false);
}
// Check if already grouped using the cell's DataGridContext
canDrop = !GroupingHelper.IsAlreadyGroupedBy(cell);
if (canDrop)
{
// Get the HierarchicalGroupByControl for this HierarchicalGroupByControlNode
HierarchicalGroupByControl parentGBC = GroupingHelper.GetHierarchicalGroupByControl(this);
if (parentGBC == null)
{
throw new DataGridInternalException("The hierarchical group-by control node must be rooted by a HierarchicalGroupByControl.");
}
DataGridContext parentGBCDataGridContext = DataGridControl.GetDataGridContext(parentGBC);
Debug.Assert(parentGBCDataGridContext != null);
if (parentGBCDataGridContext.Items != null)
{
canDrop = parentGBCDataGridContext.Items.CanGroup;
}
if (canDrop)
{
canDrop = GroupingHelper.IsColumnManagerCellInDataGridContext(parentGBCDataGridContext, cell);
if (canDrop == true)
{
canDrop = GroupingHelper.ValidateMaxGroupDescriptions(DataGridControl.GetDataGridContext(draggedElement));
}
}
}
}
else
{
hierarchicalGroupByItem = draggedElement as HierarchicalGroupByItem;
if (hierarchicalGroupByItem == null)
{
canDrop = false;
}
if (canDrop)
{
HierarchicalGroupByControl parentGBC = GroupingHelper.GetHierarchicalGroupByControl(this);
if (parentGBC == null)
{
throw new DataGridInternalException("The hierarchical group-by control node must be rooted by a HierarchicalGroupByControl.");
}
// Try to get the HierarchicalGroupByControlNode in which this HierarchicalGroupByItem can be added using the parent HierarchicalGroupByControl => null it can't
HierarchicalGroupByControlNode draggedHierarchicalGroupByControlNode = parentGBC.GetHierarchicalGroupByControlNodeFromHierarchicalGroupByItem(hierarchicalGroupByItem);
if (draggedHierarchicalGroupByControlNode == null)
{
canDrop = false;
}
}
}
}
bool returnedValue = ((cell != null) || (hierarchicalGroupByItem != null)) &&// ColumnManagerCell or HierarchicalGroupByItem
(canDrop);
return(returnedValue);
}
bool IDropTarget.CanDropElement(UIElement draggedElement)
{
bool canDrop = this.AllowGroupingModification;
ColumnManagerCell cell = null;
HierarchicalGroupByItem hierarchicalGroupByItem = null;
if (canDrop)
{
cell = draggedElement as ColumnManagerCell;
if (cell != null)
{
ColumnBase parentColumn = cell.ParentColumn;
if ((parentColumn == null) || (!parentColumn.AllowGroup))
{
return(false);
}
// Check if already grouped using the cell's DataGridContext
canDrop = !GroupingHelper.IsAlreadyGroupedBy(cell);
if (canDrop)
{
DataGridContext thisDataGridContext = DataGridControl.GetDataGridContext(this);
if (thisDataGridContext.Items != null)
{
canDrop = thisDataGridContext.Items.CanGroup;
}
if (canDrop)
{
canDrop = GroupingHelper.IsColumnManagerCellInDataGridContext(thisDataGridContext, cell);
if (canDrop == true)
{
canDrop = GroupingHelper.ValidateMaxGroupDescriptions(DataGridControl.GetDataGridContext(draggedElement));
}
}
}
}
else
{
hierarchicalGroupByItem = draggedElement as HierarchicalGroupByItem;
if (hierarchicalGroupByItem == null)
{
canDrop = false;
}
if (canDrop)
{
// Try to get the HierarchicalGroupByControlNode in which this HierarchicalGroupByItem can be added using the parent HierarchicalGroupByControl => null it can't
HierarchicalGroupByControlNode draggedHierarchicalGroupByControlNode = this.GetHierarchicalGroupByControlNodeFromHierarchicalGroupByItem(hierarchicalGroupByItem);
if (draggedHierarchicalGroupByControlNode == null)
{
canDrop = false;
}
}
}
}
bool returnedValue = ((cell != null) || (hierarchicalGroupByItem != null)) && // ColumnManagerCell or HierarchicalGroupByItem
(canDrop);
return(returnedValue);
}
