private void UpdateChildren(KTreeNodes newChildren)
{
Children.Owner?.BeginUpdate();
try
{
Children.Clear();
_placeholder = CreatePlaceholder(State, newChildren);
if (_placeholder != null)
{
Children.Add(_placeholder);
}
if (newChildren != null)
{
foreach (KTreeNode child in newChildren)
{
Children.Add(child);
}
}
}
finally
{
Children.Owner?.EndUpdate();
}
}
protected virtual string GetPlaceholderText(LoadingState state, KTreeNodes children)
{
if (PlaceholderText == null)
{
return(null);
}
return(PlaceholderText(Children.Parent, state, children));
}
public KTree()
{
SetStyle(ControlStyles.ResizeRedraw, true);
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.Selectable, true);
BackColor = SystemColors.Window;
_rootNodes = new KTreeNodes(this);
SetupRenderer();
InitScrollBars();
}
protected virtual KTreeNode CreatePlaceholder(LoadingState state, KTreeNodes children)
{
string text = GetPlaceholderText(state, children);
if (string.IsNullOrEmpty(text))
{
return(null);
}
KTreeNode node = new KTreeNode(text);
node.HasCheckBox = false;
node.IsSelectable = false;
return(node);
}
private void StartLoadChildren()
{
// Set the loading placeholder
State = LoadingState.Loading;
UpdateChildren(null);
// Load children asynchronously
KTreeNode node = Children.Parent;
OnBeginLoading(node);
KUITask
.New(() =>
{
return(DoLoadChildren(node));
})
// Continuation in UI thread
.OnSuccess(result =>
{
// Loaded successfully, render
KTreeNodes childrenTemp = new KTreeNodes(node);
DoRenderChildren(node, result, childrenTemp);
State = LoadingState.Loaded;
return(childrenTemp);
}, true)
.OnError(error =>
{
Logger.Instance.Error(this, "Exception while fetching child nodes: {0}", error);
// On error return an empty node list
State = LoadingState.Error;
return(new KTreeNodes(node));
}, true)
.OnCompletion(children =>
{
// Update nodes (or plaaceholder) and notify we're done
UpdateChildren(children);
OnEndLoading(node);
}, true)
.Start();
}
public KTreeNodeLoader(KTreeNode parent)
{
Children = new KTreeNodes(parent);
}
virtual protected void DoRenderChildren(KTreeNode node, object loaded, KTreeNodes children)
{
RenderChildren(node, loaded, children);
}
