private bool RemoveVisualElement(DesignSurfacePair <VisualElement> pair)
{
// we don't allow the root element to be removed.
if (pair.XenWidget.Parent == null)
{
return(false);
}
var parentId = pair.XenWidget.Parent.Id;
var parentPair = this[parentId];
if (parentPair == null)
{
return(false);
}
// this is the only child of the content page
if (parentId == Root.Id)
{
var page = parentPair.VisualElement as ContentPage;
if (page != null)
{
page.Content = null;
return(true);
}
}
// this maybe a layout control
var viewContainer = parentPair.VisualElement as IViewContainer <View>;
var childView = pair.VisualElement as View;
var parentView = parentPair.VisualElement;
// we can only remove view types; this shouldn't happen.
if (childView == null)
{
return(false);
}
// is this a content property?
if (viewContainer == null && ElementHelper.HasContentProperty(parentView))
{
ElementHelper.ClearContentProperty(parentView);
}
// is it a layout control? i.e. stacklayout, grid..
if (viewContainer == null)
{
return(false);
}
// made it this far, it's a layout control.
viewContainer.Children.Remove(childView);
return(true);
}
private bool RemoveXenWidget(DesignSurfacePair <VisualElement> pair)
{
var child = pair.XenWidget;
var parent = child.Parent;
if (parent == null)
{
return(false);
}
if (!parent.Children.Contains(child))
{
return(false);
}
parent.Children.Remove(child);
return(true);
}
public override DesignSurfacePair <VisualElement> this[string id]
{
get
{
// No hierarchy exists, so we return null.
if (Root == null)
{
return(null);
}
if (string.IsNullOrWhiteSpace(id))
{
return(null);
}
VisualElement ve;
if (_lookup.ContainsKey(id))
{
ve = _lookup[id];
}
else
{
return(null);
}
// Placing the recursive lookup here to save cycles if the view is not "cached"
var all = Root.GetNodeAndDescendants();
var match = all.FirstOrDefault(w => w.Id != null && w.Id.Equals(id));
var result = new DesignSurfacePair <VisualElement>
{
XenWidget = match,
VisualElement = ve
};
return(result);
}
}
private void SetAttachedProperty(object value, AttachedPropertyInfo attachedProperty, DesignSurfacePair <VisualElement> pair)
{
var set = value;
if (set != null && (value.Equals("NULL") || value.Equals("null")))
{
set = null;
}
if (set != null)
{
set = Convert.ChangeType(value, attachedProperty?.GetMethod.ReturnType);
}
try
{
attachedProperty?.SetMethod.Invoke(null, new[] { pair.VisualElement, set });
}
catch (ArgumentException)
{
// ignored for now; this should be logged and the user should be notified with a validation message
}
catch (Exception)
{
// ignored for now; this should be logged and the user should be notified with a validation message
}
}
/// <summary>
/// Attach the child view to the parent.
/// Once attached, the visual tree will be rebuilt.
/// </summary>
/// <param name="child"></param>
/// <param name="parent"></param>
/// <returns>
/// Returns true if attached; otherwise, false.
/// </returns>
public override bool SetParent(VisualElement child, DesignSurfacePair <VisualElement> parent)
{
return(SetParent(child, parent.VisualElement));
}
