Bind +/- images to slider? - silverlight

Hi I have an image of a '-' to the left of my slider, and an image of a '+' to the right.
How do I bind these images such that if they are clicked on they will increase or decrease the slider by my value of SMALLCHANGE?
Thanks.

Mind that the easiest way is to just name your Slider, handle the Image.MouseLeftButtonUp in the UserControl and change its value in code behind. If you doesn't plan to reuse this behavior, there is no need to do any further.
To make this behavior reusable, there are several approaches. Initially I'd suggest using a EventTrigger in the image with a CallMethodAction bound to the Slider, but the Slider does not has methods like LargeIncrement, SmallIncrement, LargeDecrement, SmallDecremenet. You could subclass it and implement these methods yourself, though.
Another option is to create an AttachedProperty like "IncrementSlider" to the Image (or any FrameworkElement), which would receive a Slider instance through a ElementName binding. In the PropertyChangedCallback (see this) of the PropertyMetadata, you could subscribe to the MouseLeftButtonUp event of the control and modify the Slider. You could create other attached properties as well, like "DecrementSlider", "SmallIncrementSlider", as well.
A better solution than the AttachedProperty in this case would be an AttachedBehavior. You can create a behavior to a FrameworkElement (or just Image) with a Slider property and other control properties, like "IncrementOrDecrement" and "SmallOrLarge". In the behavior's OnAttached method you would subscribe to the MouseLeftButtonUp of the control to update the Slider (if there is one available). You could then attach the behavior to the Images, bind the Slider property of the behavior to the desired Slider, and configure it to each of them, to increment or decrement in large or small steps.

Related

How to change panel width when panel's width is already binded to a Storyboard

I have applied a storyboard animation at design time to change a stackpanel width. But when I explicitly change same control's width on a button click, then there is no change in its width.
When I do not apply any storyBoard at design time, then width change works.
Is there any way to remove storyboard binding from a panel control and apply same whenever I want on a button click.
thanks
DependencyPropertys react to change requests from different sources with different precedences. You can find out more in the Dependency Property Value Precedence article on MSDN. In your situation, the change requests to the StackPanel.Width DependencyProperty sent from the Animation object override any changes made in a Trigger Setter object.
The easiest thing to do is to pause or stop the Storyboard in the Button.Click handler before you change the StackPanel.Width. See this post which deals with a similar situation. You can find further information in the MSDN Storyboard.Pause Method article.

Windows Phone Setting Visibity of an Element based on ImageOpened event

I'm trying to find a way to set the visibility of a Visual element based on the completion of an loading and display state of Image Element.
Is there a property I can bind to on an Image that will indicate display state?
Note: The app is using MVVM so I would like to avoid code behind if at all possible.
You could avoid the code behind by creating a behavior that hooks into the events and sets the visibility. Then you can attach this behavior to your images using xaml.
You will need to use the ImageOpened and ImageFailed events and then set the visibility in code behind.
There is no member of the Image control that will give you the state of the image.

WPF scrollviewer

Is there a posibility to scroll to a specific place in a ScrollViewer from your code behind?
So something like the Slider element you can change the value property...
You need the ScrollToHorizontalOffset and ScrollToVerticalOffset methods.
Annoyingly, there aren't corresponding (settable) properties, so you can't databind the scroll position, but these methods do at least let you set it from code.
In most cases if you're trying to show a specific control it's simpler to call BringIntoView on any FrameworkElement (Panel, Control, etc) contained in the ScrollViewer which will take care of all the size and offset calculations for you.

How can I get WPF binding to occur on controls which have not yet been shown?

I have a custom text box control which raises a routed event when its TEXT property changes. This text property is data bound to a property on our view-model object.
When I place this control on a TabControl page or Expander control, it appears as if data binding only occurs when the control becomes visible for the first time, therefore I never receive any of the routed events until I swap to the tab the control is on or expand the expander.
Is there any way I can force data binding to occur before the control is shown?
Sounds like you relying on the data binding to genreate the routed event is the wrong approach. Instead you need to have your Model or ViewModel generate an event when the text is modified and then you watch this event from an appropriate place in your View.
Not very likely. WPF is a fairly efficient framework and won't do any work that it doesn't absolutely have to. This includes scenarios like data binding. Why bother exercising a collection for a control that might not ever be shown?

WPF: binding seletion of text to sliders?

In a WPF based project I would like to bind the content of a TextBox to two sliders in such a way that first slider would start selection (from left or right based on a checkbox) from the
n-th character (n being slider value) to the m-th character (based on second slider value).
In essence I would like to specify selection range based on slider values.
How can I achieve it?
Ideally, you would bind TextBox.SelectionStart and TextBox.SelectionLength to values from the slider. (Probably via a converter that implements IMultiValueConverer)
Unfortunately, you can't, because you can only bind Dependency Properties, and SelectionStart and SelectionLength are not dependency properties.
To solve this problem you would have to handle the OnValueChanged event on the sliders, then update the SelectionStart and SelectionLength properties via code in the event handler.
Disappointing answer - I bet you were hoping for some slick XAML code :-)

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