I want to calculate enter image description here automation id of text block inside the content presenter. My visual tree looks like this-
You can use System.Windows.Media.VisualTreeHelperto determine any control in visual tree.
There are two helpful methods
System.Windows.Media.VisualTreeHelper.GetParent(DependencyObject reference)
to go up in tree hierarchy
System.Windows.Media.VisualTreeHelper.GetChiled(DependencyObject refernce, int childIndex)
to go down in tree hierarchy
See more: VisualTreeHelper
Related
I created a WPF steckflow project under Expression Blend 2013.
I would like to sketch a navigation tree to demonstrate how users can select items in a tree. The tree should represent categories at the first level (Cat 1, Cat 2, ...) and items should be under each category node. It should be pretty similar to the navigation tree of the Assets in Blend.
How can I sketch this tree?
Thank you
Right so what you're referring to is called a TreeView that you can find and use by going to your "Assets" tab and choosing "Controls" then selecting the TreeView and dragging it to your design surface. Then of course you'll have to add items and sub-items to it.
Hope this helps. Cheers
I'm new to WPF and tyring to uderstand the best way I can modify any given control attributes. What I was trying to achieve is to show tooltip for a cell. Yes a quick google and can see xaml of how to do it. But I want to understand how can one learn to figure out this out using some tool.
I came across Snoop that can show visual tree of a control very easily (CTRL+SHIFT Mouse over). What I'm trying to understand is if one knows of visual tree, how can one change it? For example, let's say I use WPF DataGrid and bind it to a source and display column using DataGridTextColumn.
<DataGridTextColumn Header="First Name" Binding="{Binding FirstName}">
Now let's say I want to show tooltip for each cell. So I fire up Snoop and CTRL+SHIFT mouse over the cell. Snoop shows me that its a DataGridCell that is using Border and withing it ContentPresenter which ends up using TextBlock to show the value. So that means that if I can somehow access that textblock, I can set its tooltip property using binding. Issue is that I don't know how I can access it in xaml.
In other words, knowing a visual tree, how can one access it in xaml for any given control. This will also be very handly for 3rd party controls.
Thanks
Your'e asking quite a bit here, and i'm not sure I completely understand your intention, so I hope I got this right. Your'e asking if you can access the complete visual representation of each control and change it using xaml. The answer to that is yes, but you shouldn't.
I'll get to what I mean in a bit, but first I'd like to clarify some concepts, since i'm not sure you're using them correctly.
XAML:
Xaml is the declarative markup representation of your views and nothing more. Xaml syntax directly corresponds to it's respective classes and their properties. Xaml maps tags to classes and attributes to properties. It's a small distinction, but it's important to think this way. Everything you can do in xaml you can also do in code (although it would often be much more work). Again: xaml refers to markup code only.
<ClassA PropertyA="Value">
<ClassA.PropertyB>
<ClassB />
</ClassA.PropertyB>
Default property value
</ClassA>
Logical tree:
The logical tree is the runtime representation of your xaml code. it consists (mostly) of the controls you set in your xaml files.
Visual tree:
The visual tree is the visual representation the logical tree. It contains much more since it contains the concrete visual representation of everything displayed in your view. Most of the logical tree can't be directly displayed. WPF uses Data and Control Templates together with Styles to determine exactly how each object is supposed to look. In case of data templates that can also mean simple data objects and not only WPF controls.
Now for your question: so can you access the concrete visual representation of each control?
Yes, but you'll have to use control templates to manipulate it's visuals. Also, control templates are usually applied to control types and not specific controls, so you'll have to deal with that as well.
And that's why you shouldn't access it. The xaml representation usually gives you all you need to modify your control, and even if you do use templates you shouldn't change every last piece of it. Templates are used to style a control, so only write enough to show it as you wish. There's no need specify everything.
However you can access the entire visual tree more easily using procedural code, if you use the VisualTreeHelper class (that's how snoop does it, by the way). Using it you can traverse the visual tree and access all it's classes and members. If you really want to access every single visual object you'll do it much more easily with the VisualTreeHelper.
If in my wpf application there are multiple grids and a dragable user control.Can anyone suggest code that could return different grid id every time the control is dragged over different grids.
You can use Mouse.DirectlyOver then go up the visual tree to find the first Grid up the tree.
Mouse.DirectlyOver returns the IInputElement that is under the mouse at the time you check the property.
You can walk up the visual tree using a method described in this SO question
Edit: I found the SO question about visual tree walking i was thinking about. (much better than the first link IMHO).
We have a WPF application (.Net 4.0) using a Docking Control (Actipro). We can dock out the docking windows. In that case, a "real" Window is created and the content is assigned to that window.
Of course, moving stuff in the Visual Tree will re-trigger the complete layouting. This is problematic, because in one of these docking windows, we have a diagramming control (Mindfusion Diagramming,WPF control) that can take up to 10 seconds to completely layout itself (very large diagrams).
I don't think that there's any direct solution to this problem. I wonder however how other programmers with similar issues approached this problem. Is there any clever way to avoid recalculating the layout?
In theory, nothing really changes since the diagram is inside a ScrollViewer, so whenever it is placed, the amount of avaiable space remains the same(infinite).
Edit: Also note that the diagram control inside is interactive. We need Drag&Drop.
Here is an idea.
Create a custom class inheriting from Decorator.
Wrap your diagramming control inside the decorator.
Override MeasureOverride and simply call base.Measure but store the result in a field before returning.
Add a property which enables you to disable the measure call. If the property is true simply return the previous size in MeasureOverride instead of calling base.Measure.
Set the property while changing the visual hierarchy.
From the top of my head I can't think of any reason why this shouldn't work.
I have actually done something very similar not too long ago. When implementing the sliding animation for the side panels in NovaMind I used a Decorator to prevent the content from performing layout while the panel animates its width. I calculated the size with the final width, stored it and then used MeasureOverride to fake the current size... This prevented the performance issues involved when trying to animate the width of a complex control. :)
Another possibility is that the problem isn't related to layout so much as the "severing" of the visual tree when moving the content from one window to another. This seems to cause a slew of recalculations for dependency properties, which if your visual tree for content was like mine, upwards of 2000 controls, it was really slow.
I couldn't find an elegant solution to this using Actipro docking library itself, so I thought how I could divert WPF from doing this behavior. The solution I came up with was to create my content as a single WinFormsHost control with a single child of a WinForms UserControl. Then, I made that WinForms UserControl have it's content be the WPF based content that should appear as the docking window content. I figured that when WPF started walking the visual tree from the top to re-evaluate all dependency properties when the tree was "snipped", it would run into the WinForms control and stop.
My Actipro docking tool windows used to take 6 seconds or so just to switch tabs or to float. Now they are essentially instaneous. You have to ensure that any command handlers are not at the application level, but instead at your WPF content level and you might have to finagle wtih the location of some style files, but it worked fantastic.
you might want to replace your diagramming control in the visual tree with an Image, render the diagram offscreen and use rendertargetbitmap to convert the rendered diagram to an image, which you can use as the source for the Image in the visual tree.
something like this:
// image is the Image from the visual tree
int h = image.ActualHeight;
int w = image.ActualWidth;
// layout the diagram to the size of the image
diagram.Measure(new Size(w, h));
diagram.Arrange(new Rect(newSize(w,h)));
diagram.UpdateLayout();
// render the diagram to a bitmap
RenderTargetBitmap bmp = new RenderTargetBitmap((int)w, (int)h, 96, 96, PixelFormats.Default);
bmp.Render(diagram);
// set the source of your image to the bitmap
image.Source = bmp;
in the example if PixelFormats.Default doesn't seem to work, you might try PixelFormats.Pbgra32, which I think is a more common format to use in this type of thing.
you might also be able to use a VisualBrush in a similar manner. I can imagine in the long run you could probably create a wrapper class for the diagram to automatically display the image copy and re-layout the diagram only if something changes (ie a part of the diagram or the size).
I'm looking for a 2 sided winform Tree control. something like what you see in the math books. meaning that the tree can go both right and left in the control.
Something like http://www.math.bas.bg/~nkirov/2010/NETB201/slides/ch06/pic3.jpg
Thanks
Avi
You can possibly create a control for yourself deriving from the treeview and doing all the styling in the derived control. But I am sure it will be tedious thing. If you need to just show some data, in that case you can think of using SVG (its an XML inside) so that you can change data as you wish. Otherwise, think of WPF.