//------------------------------------------------------------------- // // Internal Methods // //------------------------------------------------------------------- // // ProcessTemplateBeforeSeal // // This is used in the case of templates defined with FEFs. For templates // in Baml (the typical case), see the OnApply override. // // 1. Verify that // a. root element is a Panel // 2. Set IsItemsHost = true // internal override void ProcessTemplateBeforeSeal() { FrameworkElementFactory root; if (HasContent) { // This is a Baml-style template // Validate the root type (it must be a Panel) TemplateContent templateHolder = Template as TemplateContent; System.Xaml.XamlType panelType = templateHolder.SchemaContext.GetXamlType(typeof(Panel)); if (templateHolder.RootType == null || !templateHolder.RootType.CanAssignTo(panelType)) { throw new InvalidOperationException(SR.Get(SRID.ItemsPanelNotAPanel, templateHolder.RootType)); } } else if ((root = this.VisualTree) != null) { // This is a FEF-style template if (!typeof(Panel).IsAssignableFrom(root.Type)) { throw new InvalidOperationException(SR.Get(SRID.ItemsPanelNotAPanel, root.Type)); } root.SetValue(Panel.IsItemsHostProperty, true); } }
// workaround, pending bug 953483. The panel is // being removed from the tree, so it should release // its resources (chiefly - stop listening for generator's // ItemsChanged event). Until there's a mechanism for // this, just mark the panel as a non-ItemsHost, so // that the next time it gets ItemsChanged it will // stop listening. (See also bug 942265) private void ClearPanel() { Panel oldPanel = (this.VisualChildrenCount > 0) ? this.GetVisualChild(0) as Panel : null; Type type = null; if (Template != null) { // Get the type of the template content's root // Is this a FEF-based template? if (Template.VisualTree != null) { type = Template.VisualTree.Type; } // Or, is it a (non-empty) Baml-based template? else if (Template.HasXamlNodeContent) { System.Xaml.XamlType xType = (Template.Template as TemplateContent).RootType; type = xType.UnderlyingType; } } if (oldPanel != null && oldPanel.GetType() == type) { oldPanel.IsItemsHost = false; } }