Develop Reference

WPF hide slider track

I'm using WPF (and the MVVM framework) to create an interface which has a slider on it.
<Slider Value="{Binding MotorDemandSpeed}" Maximum="3500" />
I'm trying to hide the track part on the slider so that you are left with just the 'thumb tack'. This is what the slider currently looks like (styles are controlled by a theme):
I've looked around at various methods, however I can't find a method that changes only a single slider.
Help is appreciated.

You need to set the Template property of this particular Slider instance to be able to override its ControlTemplate:
<Slider Value="{Binding MotorDemandSpeed}" Maximum="3500">
<Slider.Template>
<ControlTemplate TargetType="Slider">
<!-- define the custom template without a track here... -->
</ControlTemplate>
</Slider.Template>
</Slider>

In order to change the appearance of a control you will need to modify the control template. Each control is made up of many parts, and each part many objects. You can modify individual parts (such as the track) with the correct x:Key and TargetType.
This Question has an example of modifying a scrollbar control template, which is most likely similar to the template of this slider you have. The first step would be to identify the Xaml file in your theme which this slider uses and find the parts that define the trackbar, thumb, etc. From there you should be able to recreate the control to your liking, or just completely remove parts you do not need.
Are you using any third party controls that may have information on how to edit their themes? Perhaps try investigating Modifying Control Templates to get a better understanding of control templates.
Here is the MDSN page for the slider control template, you may find this useful.

Do I need dependency properties for all basic properties on my user control?

I am currently writing my first user control which would consist of a label and a text box in a stack panel like follows:
<Grid>
<StackPanel Orientation="Horizontal" DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Label Content="{Binding Label}" Width="60"></Label>
<TextBox Text="{Binding TextBoxContent}" Width="60"/>
</StackPanel>
</Grid>
This will be most useful to be in a settings page, as it will be reused for several different settings. With each of these settings, I will want to set (at a minimum) the width, height, validation rule and error template properties. As for the text itself, I have already created a dependency property both for the label and the text box (as you can see in my snippet above).
My question is this: Do I need to create a dependency property for all of the properties I just mentioned that I would like to set when I actually use my user control? This seems like redundant work (since they already exist on the text box, basically they would just redirect my user control's property to the text box's property of the same name)? This is even more work if I want to use even more properties on my text box (for example, AcceptsReturn, etc).

The redundant work can be saved if you decide to derive from TextBox rather than UserControl - just think of your control as a "labeled textbox" and all you need to do is derive from TextBox and add the needed dependency properties to accommodate for the label. This of course would not be the case for more complex user controls, but it seems OK in your case.
The downside to this though is that you'll have to take the default control template for TextBox and work with it to add your label, which may be a bit trickier.
Either way, I recommend having a look at the Control Authoring Overview page on MSDN, which is extremely useful when writing your first controls in WPF.

Force Refreshing WPF Bindings (one source)

I have this situation:
A IsToolbarButtonsEnabledProperty DependencyProperties
A have plenty of other DependencyProperties in a class (a huge class, needs to be this way)
A serie of Buttons on a toolbar.
The (IsEnabled) property of each of these buttons is a function of (IsToolbarButtonsEnabledProperty) throught a special converter, the buttons a differenced by ConvertParameter ("PreviousButton", "NextButton"...)
Opacity="{Binding IsEnabled, RelativeSource={RelativeSource Self}, Converter={StaticResource OpacityBoolToIntConverter}, UpdateSourceTrigger=PropertyChanged}"
IsEnabled="{Binding Path=DPEnableLinks, Converter={StaticResource ToolButtonEnableConverter}, ConverterParameter='ZoomOut' }"
ToolButtonEnableConverter is a converter that compares ConverterParameter "PreviousButton" with other value of other dependency property (in class). I have to many DP to make one multivalueconverter, so I read them straight from my class ((MainWindow)App.Current.MainWindow;)
Questions
When I update other DPs the value isEnabled / Opacity, dont change. How to fix this?
Is there a general solution to make a Binding refresh everytime a DP changes.
(Repeating myself): I will be adding more and more DPs over time, so a MultiValueConverter seams odd.

One way to force the Binding to update is to create a (meaningless) property and add it to the Binding (using MultiBinding), and when you want to update your Binding you change that property, and all the Binding is updated.
I must add that the more "straightforward" way is to use MultiBinding to all the relevant properties. If you have way to many properties that you need to bind, maybe you should re-think if you can build this functionality some other way.

Change inner user control in Silverlight/WPF by a property at design time

I am creating some custom user controls for WPF. This user controls contain custom dependency properties so I can fill them in the designer.
One of this properties is called "InnerUserControlType". This dependency proeprty is a custom enumeration containing some values like TextBox, ComboBox, Label, CheckBox, etc.
I would like to be able to set this property in my XAML pages in the designer and then see the user control change the displayed inner control depending on the property.
How should I implement this? The grid which will contain the inner control in my user control is a normal field, so it cannot be accessed from a static method property (like the dependency properties).
I want it to have it working in the designer so the designers can work easily.
Thanks a lot!

Put a ContentControl in the grid, bind the Content property to the UserControl via relative source
<ContentControl Content="{Binding RelativeSource={RelativeSource FindAnsector,
AncestorType={x:Tyle myNamespace:MyControl}}}"
and make a DataTemplateSelector that will check the value of InnerUserControlType and will return an appropriate data template containing the control that was asked for in the property.
Depending on your scenarios, you might need to make sure the controls in the data template have the right data context. If the data context of the controls should be the same as of the user control, then on the root element in the data template, add relative binding for data context. Something like (for the text box data template):
<TextBox DataContext="{Binding DataContext,
RelativeSource={RelativeSource FindAnsector,
AncestorType={x:Tyle myNamespace:MyControl}}}"
......
</TextBox>
EDIT:
I've noticed only the wpf tag and missed the silverlight one.
In Silverlight you don't have ...TemplateSelector properties, so use a converter instead.

Difference between Style and ControlTemplate

Could you tell me what is the main differences between Style and ControlTemplate ?
When or why to use one or the other ?
To my eyes, they are exactly the very same. As I am beginner I think that I am wrong, thus my question.

In a style you set properties of a control.
<Style x:Key="MyButtonStyle" TargetType="Button">
<Setter Property="Background" Value="Red"/>
</Style>
<Button Style="{StaticResource MyButtonStyle}"/>
All buttons that use this style will have their Backgrounds set to Red.
In a template you define the UI (structure) of the control.
<ControlTemplate x:Key="MyButtonTemplate" TargetType="Button">
<Grid>
<Rectangle Fill="Green"/>
<ContentPresenter/>
</Grid>
</ControlTemplate>
<Button Template="{StaticResource MyButtonTemplate}"/>
All buttons that use this template will have a green background that cannot be changed.
Values set in a template can only be replaced by replacing the entire template. Values in a style can be replaced by setting the value explicitly when using the control. That is why is better to use the properties of the control by using TemplateBinding instead of coding values.
<ControlTemplate x:Key="MyButtonTemplate" TargetType="Button">
<Grid>
<Rectangle Fill="{TemplateBinding Background}"/>
<ContentPresenter/>
</Grid>
</ControlTemplate>
Now the template uses the value of the Background property of the button it is applied to, so it can be customized:
<Button Template="{StaticResource MyButtonTemplate}" Background="Yellow"/>
Another useful feature is that controls can pick up a default style without having a specific style being assigned to them. You can't do that with a template.
Just remove the x:Key attribute of the style (again: you can't do this with templates). All buttons in the visual tree below the style will have this style applied.
Combining Templates and Styles is extra powerful: you can set the Template property in the style:
<Style TargetType="Button">
<Setter Property="Background" Value="Red"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid>
<Rectangle Fill="{TemplateBinding Background}"/>
<ContentPresenter/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

No indeed you are quite wrong.
Styles set properties on controls. ControlTemplate is a property shared by most controls that specify how they are rendered.
To elaborate, you can use a style to group settings for a bunch of properties so you can re-use that to standardize your controls. Styles can be set explicitly on controls or applied too all of a certain type.
Control Templates can be set by a style or set explicitly on a control to change the way it appears. All controls have default templates (and styles for that matter) that are embedded in the .net wpf assemblies. It is quite enlightening to see these and understand how the wpf developers implemented the normal versions of all controls. If you have Expression blend installed, look in its "SystemThemes" folder.
UPDATE:
To understand how Styles and ControlTemplates can "add controls". In some way or another, the ControlTemplate is the only way to define the controls a control is made up of. But, some default .net controls allow you to use controls in place of text.
For example:
<GroupBox>
<GroupBox.Header>
<CheckBox/>
</GroupBox.Header>
</GroupBox>
This "adds" a checkbox to the groupbox without changing the ControlTemplate, but this is because the default ControlTemplate for GroupBox allows anything as the Header. This is done by using special controls such as ContentPresenter.
However, sometimes the default ControlTemplate for a control doesn't allow you to change something that you want to change via properties. Then you must change the ControlTemplate.
Whether you set the Properties of a control (Content, Header, ControlTemplate, IsEnabled, etc.) directly or via a style does not matter, Styles are only a convenience.
Hopefully this answers your question more clearly.

You can think of a Style as a convenient way to apply a set of property values to more than one element. You can change the default appearance by setting properties, such as FontSize and FontFamily, on each TextBlock element directly. However, if you want your TextBlock elements to share some properties, you can create a Style in the Resources section of your XAML file.
On the other hand, a ControlTemplate specifies the visual structure and visual behavior of a control. You can customize the appearance of a control by giving it a new ControlTemplate. When you create a ControlTemplate, you replace the appearance of an existing control without changing its functionality. For example, you can make the buttons in your application round instead of the default square shape, but the button will still raise the Click event.
Ref: http://msdn.microsoft.com/en-us/library/ms745683.aspx

I found some interesting differences in
The difference between styles and templates (msdn)
Style:
You can set only pre-existing properties in the style. For example, you cannot set a default value for a property that belongs to a new part that you added to the template.
Template:
When you modify a template, you have access to more parts of a control than when you modify a style. For example, you can change the way the pop-up list appears in a combo box, or you change the look of the button that triggers the pop-up list in the combo box by modifying the items template.
Style:
You can use styles to specify the default behavior of a control. For example, in a style for a button, you can specify a trigger so that when users move their mouse pointer over the button, the background color will change. These property changes are instantaneous (they cannot be animated gradually).
Template:
You can specify the behavior of any new and existing parts in a template by using triggers. For example, you can specify a trigger so that when users move their mouse pointer over a button, the color of one of the parts will change. These property changes can be instantaneous or animated gradually to produce a smooth transition.

OK, I had the exact same question and the answers I found in this thread pointed me in the right direction so I'm sharing, if only so I can understand it better myself.
A Style is more flexible than a ControlTemplate.
From Windows Presentation Foundation Unleashed, Adam Nathan and gang (writers) state this:
"Besides the convenience of combining a template [with a style using the Style's ControlTemplate setter] with arbitrary property settings, there are important advantages of doing this [setting the ControlTemplate setter on a style]:
It gives you the effect of default templates. For example, when a typed Style gets applied to elements by default, and that Style contains a custom control template, the control template gets applied without any explicitly markings on those elements.
It enables you to provide default yet overridable property valus that control the look of the template. In other words, it enables you to respect the templated parent's properties but still provide your own default values."
In other words, creating a style allows the user of the Style's Template setter to override the values set, even if they did not use a TemplateBinding ({TemplateBinding Width} for example). If you hardcoded the Width in your style, the user of the Style could still override it, but if you hardcoded that Width property in a Template, the user is stuck with it.
Also, (and this is kind of confusing) when using a ContentTemplate with a TemplateBinding the onus is on the user to set that property otherwise it will use the default property for the TargetType. If you use a style, you can override the default property of the TargetType by using a setter for the property and then applying a TemplateBinding referencing back to that setter. The book explains it better, page 338 (Mixing Templates with Styles)