I'm writing the WPF app that uses TreeView control inside the UserControl. TreeView control has the same width as the UserControl.
The problem is that I need to make the children nodes to have the full with of the TreeView. I can't assign the width by the static expression as well as UserControl that contains TreeView may have variable width.
I thought that the solution can be reached by assigning the TreeView child item the width of the UserControl. But if I do so the TreeView child item will be out of control, as well as there is margin in the children item. For example
Item A
---Item B
Can you tell, how can I get the width of --- ? Or to make ItemB be under the Item A without using static margin metrics?
Thank you
You can edit the Style of TreeViewItem and make its Horizontal Alignment as Stretch instead of Left. Also ensure you host your ContentPresenter inside the Grid.
In this case, eventhough the header text seems to be leeser in width, the mouse hover or Selected color will cover the entire width of treeview. I hope that is what you need.
Related
I've been making a custom style for TabControls and TabItems for a program I'm designing, and would like to know if it's possible to have it so that if all TabItems in a TabControl have the property Visibility="Collapsed", the TabControl's TabPanel (where the tabs are displayed) can be collapsed or otherwise completely hidden. This is of course a default behaviour in TabControls, but since they're using a custom style (so they are no longer fugly, and are consistent with the theme of the application) this behaviour seems to have disappeared (likely because as of now I have the Height property set to a hardcoded value)... which brings me to my next point, the height of the TabPanel - when tabs are visible - should be several pixels more than the height of the tabs. Of course this makes using margins difficult, because that extra height should be removed if all TabItems are collapsed.
So to summarize, what I'm looking to do:
TabControl when any tabs are not collapsed:
TabPanel has a height of 26px (taller than the TabItems, which are 18px tall)
TabControl when all tabs are collapsed:
TabPanel is completely collpased/hidden, with zero height
Many thanks to any of you awesome people that can help me out. I've been working with WPF consecutively for long enough to fry my brain, and a simple solution to this problem escapes me (I need a break!)
Well nevermind!
This is what happens when you've spent too long working on stuff.
The solution was to give the TabItems a margin that gives the extra height above them, and then to set the TabPanel's Height property to Auto inside the TabControl's ControlTemplate. Duh!
I'm having a problem with a TreeView in WPF C#.
I have a TreeView with two TreeViewItems defined in XAML.
On the second TreeViewItem, I have a list of items defined by a binding.
When the list is too long, a vertical scrollbar appears and allows the entire TreeView to scroll.
But the two TreeViewItems must stay at the same place, so I'd like the content of the second to scroll instead, rather than the entire TreeView.
Left : what I get, and the two first items are scrolled out; Right what I'd like, with the two first items staying at the same spot. (The scrollbar is the red zone).
I look forward to hearing from you guys, and thanks in advance,
Raekh.
EDIT :
Found a solution : I removed the two treeviewitems and used a treeview with a item source obtained by binding, so the treeview starts after the treeviewitems and is scrolled properly.
I've put an Expander onto a Page. Within the expander there is a Label. After the page is loaded, the expander is not yet expanded. At this point, I inspect the Expander using VisualTreeHelper, I got a structure like this:
Expander
Border
DockPanel
ToggleButton
Border
Grid
Ellipse
Ellipse
Path
ContentPresenter
ContentPresenter
where there is no Label under the last ContentPresenter.
However, Once the expander is expanded and then collapsed, I got the a different structure using VisualTreeHelper:
Expander
Border
DockPanel
ToggleButton
Border
Grid
Ellipse
Ellipse
Path
ContentPresenter
ContentPresenter
Label
Border
ContentPresenter
This time, the Label appears under the ContentPresenter.
It seems that as long as the expander has been expanded, VisualTreeHelper will know the contents within the Expander. But is there a possible way to make VisualTreeHelper be aware of Expander's contents without expanding it?
Thanks.
There is a method for forcing a control to load its contents programmatically.
I imagine you have some sort of recursive loop that searches through your elements. Before you call to get its children, use this call:
if (element is FrameworkElement)
(element as FrameworkElement).ApplyTemplate()
That'll force it to apply its template and load the controls into memory. I imagine it is done this way for performance reasons, as controls are not normally needed until they are visible.
This approach also works for TabControl and any other control that can hide content, I believe.
Credit goes to Tao Liang who posted this solution over here. Read it also if you're having trouble with your recursive loop.
I have a WPF ListBox control which displays items of an RSS feed. I occasionally check the source of the RSS feed for new items. Once I detect a new item I add it to the observable collection which immediately adds the new item to the ListBox display.
Is there a way to 'slide in' the new item from the top, pushing down the existing items? How would I achieve such an effect? Can it be done with a ListBox, or do I need to resort to my own container, such as a StackPanel and animate for example the Height of newly added controls programmatically?
I just posted an answer to this question which is very similar to yours.
WPF how to animate a list of components
It can be done with a ListBox. Use the ItemContainerStyle to style the ListBoxItems that the binding creates for you: this style can include animations, e.g. by adding an EventTrigger for the Loaded event to the Style.Triggers, and transforms. For example, in your trigger action you could animate the Height so the item expands into place, or if the height is unknown you could have your style set a ScaleTransform and in your trigger action animate the ScaleY of that transform from 0 to 1.
I'm using a DataTemplate that animates a RenderTransform to increase its size when the mouse is over it. The problem I'm having is that when the animation is in effect the enlarged list box item appears behind other items. Is there a way to control the ZIndex of the list box item from within my DataTemplate so that it's always on top of other items?
You can set the Templated Element's ZIndex from template using Triggers. Find out the templated parent control by VisualTree parsing like bellow
{RelativeSource FindAncestor,AncestorType=...
The zIndex is only available on elements hosted inside a Canvas. Therefore you may be able to wrap the whole listbox control in a canvas then set Canvas.zIndex to 99 as part of the Trigger you are using to do the transform . However I could not get this to work.
The only other option that did work is to use a LayoutTransform rather than a RenderTransform as this will move the other items out of the way as the transform is calculated before the items are placed. This would mean there would be no need to set any zIndex, however it would depend on your requirements.