private static bool IsDropAllowed(DirectionalDropArea dropArea, NamingRuleTreeItemViewModel target, NamingRuleTreeItemViewModel source)
{
switch (dropArea)
{
case DirectionalDropArea.On:
// Naming Rules can't be dropped on themselves or on any of their descendants.
if (source == target || source.IsAncestorOfMe(target))
{
return false;
}
else
{
return true;
}
case DirectionalDropArea.Above:
case DirectionalDropArea.Below:
// Naming Rules can't be dropped on themselves, or on any of their descendants.
if (source == target || source.IsAncestorOfMe(target))
{
return false;
}
// There must always be a single root Naming Rule
if (target.Parent == null)
{
return false;
}
// Insertions that would lead to the same order don't make sense
int direction = dropArea == DirectionalDropArea.Above ? -1 : 1;
return source.Parent != target.Parent || source.Parent.Children.IndexOf(source) != target.Parent.Children.IndexOf(target) + direction;
default:
return false;
}
}
public void OnDrop(DirectionalDropArea dropArea, DragEventArgs e)
{
if (e.Data.GetDataPresent(typeof(NamingRuleTreeItemViewModel)))
{
NamingRuleTreeItemViewModel namingRule = e.Data.GetData(typeof(NamingRuleTreeItemViewModel)) as NamingRuleTreeItemViewModel;
if (!namingRule.IsAncestorOfMe(this))
{
switch (dropArea)
{
case DirectionalDropArea.On:
namingRule.Parent.Children.Remove(namingRule);
this.Children.Add(namingRule);
break;
case DirectionalDropArea.Above:
namingRule.Parent.Children.Remove(namingRule);
this.Parent.Children.Insert(this.Parent.Children.IndexOf(this), namingRule);
break;
case DirectionalDropArea.Below:
namingRule.Parent.Children.Remove(namingRule);
this.Parent.Children.Insert(this.Parent.Children.IndexOf(this) + 1, namingRule);
break;
}
}
}
}
public void OnDrop(DirectionalDropArea dropArea, DragEventArgs e)
{
if (e.Data.GetDataPresent(typeof(NamingRuleTreeItemViewModel)))
{
NamingRuleTreeItemViewModel namingRule = e.Data.GetData(typeof(NamingRuleTreeItemViewModel)) as NamingRuleTreeItemViewModel;
if (!namingRule.IsAncestorOfMe(this))
{
switch (dropArea)
{
case DirectionalDropArea.On:
namingRule.Parent.Children.Remove(namingRule);
this.Children.Add(namingRule);
break;
case DirectionalDropArea.Above:
namingRule.Parent.Children.Remove(namingRule);
this.Parent.Children.Insert(this.Parent.Children.IndexOf(this), namingRule);
break;
case DirectionalDropArea.Below:
namingRule.Parent.Children.Remove(namingRule);
this.Parent.Children.Insert(this.Parent.Children.IndexOf(this) + 1, namingRule);
break;
}
}
}
}
private void UpdateAllowedEffects(DirectionalDropArea dropArea, DragEventArgs e)
{
if (e.Data.GetDataPresent(typeof(NamingRuleTreeItemViewModel)))
{
NamingRuleTreeItemViewModel namingRule = e.Data.GetData(typeof(NamingRuleTreeItemViewModel)) as NamingRuleTreeItemViewModel;
if (namingRule != null && IsDropAllowed(dropArea, target: this, source: namingRule))
{
e.Effects = DragDropEffects.All;
}
}
}
private void UpdateAllowedEffects(DirectionalDropArea dropArea, DragEventArgs e)
{
if (e.Data.GetDataPresent(typeof(NamingRuleTreeItemViewModel)))
{
NamingRuleTreeItemViewModel namingRule = e.Data.GetData(typeof(NamingRuleTreeItemViewModel)) as NamingRuleTreeItemViewModel;
if (namingRule != null && IsDropAllowed(dropArea, target: this, source: namingRule))
{
e.Effects = DragDropEffects.All;
}
}
}
private static bool IsDropAllowed(DirectionalDropArea dropArea, NamingRuleTreeItemViewModel target, NamingRuleTreeItemViewModel source)
{
switch (dropArea)
{
case DirectionalDropArea.On:
// Naming Rules can't be dropped on themselves or on any of their descendants.
if (source == target || source.IsAncestorOfMe(target))
{
return(false);
}
else
{
return(true);
}
case DirectionalDropArea.Above:
case DirectionalDropArea.Below:
// Naming Rules can't be dropped on themselves, or on any of their descendants.
if (source == target || source.IsAncestorOfMe(target))
{
return(false);
}
// There must always be a single root Naming Rule
if (target.Parent == null)
{
return(false);
}
// Insertions that would lead to the same order don't make sense
int direction = dropArea == DirectionalDropArea.Above ? -1 : 1;
return(source.Parent != target.Parent || source.Parent.Children.IndexOf(source) != target.Parent.Children.IndexOf(target) + direction);
default:
return(false);
}
}
public void OnDragOver(DirectionalDropArea dropArea, DragEventArgs e)
{
UpdateAllowedEffects(dropArea, e);
}
public void OnDragLeave(DirectionalDropArea dropArea, DragEventArgs e)
{
}
public void OnDragOver(DirectionalDropArea dropArea, DragEventArgs e)
{
UpdateAllowedEffects(dropArea, e);
}
public void OnDragLeave(DirectionalDropArea dropArea, DragEventArgs e)
{
}
