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How to make button highlight when hovered over using a template

Recently started WPF and am very new to XAML. I'm trying to make a calculator that looks similar to the IOS one. However, after I changed the Button to Ellipse, the highlighting when hovered over or clicking on stopped working, if also the highlighting issue were to be fixed, how would I go about changing the colour of it?
<Button x:Name="ButtonEquals" Grid.Column="4" Grid.Row="6" Width="47" Height="47"
Content="=" Foreground="White"
BorderBrush="{x:Null}" Background="#FFFF9500">
<Button.Template>
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse Fill="#FFFF9500"/>
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Button.Template>
</Button>

You can add a Trigger to the ControlTemplate and target the Ellipse by name assigning an x:Name and referring to it via TargetName. This way, you can define other states as well.
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse x:Name="MyEllipse" Fill="#FFFF9500"/>
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsDefaulted" Value="True">
<Setter TargetName="MyEllipse" Property="Fill" Value="OrangeRed"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter TargetName="MyEllipse" Property="Fill" Value="Blue"/>
</Trigger>
<Trigger Property="IsPressed" Value="True">
<Setter TargetName="MyEllipse" Property="Fill" Value="Red"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter TargetName="MyEllipse" Property="Fill" Value="Gray"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
This targets only the Fill of the Ellipse, without changing other controls in the template. However, the values are hardcoded and not changable from outside.
If you want the template to be customizable to a certain degree, then you can put it in a Style and bind properties on the templated control using TemplateBinding or a RelativeSource with TemplatedParent for two-way and special scenarios. Additionally, you can add a FocusVisualStyle that allows to specify a template for keyboard focusing.
<Style TargetType="Button">
<Setter Property="Background" Value="#FFFF9500"/>
<Setter Property="Foreground" Value="White"/>
<Setter Property="FocusVisualStyle">
<Setter.Value>
<Style>
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Ellipse StrokeDashArray="1 2" Stroke="DarkGreen" StrokeThickness="2"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse x:Name="MyEllipse" Fill="{TemplateBinding Background}"/>
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsDefaulted" Value="True">
<Setter TargetName="MyEllipse" Property="Fill" Value="OrangeRed"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter TargetName="MyEllipse" Property="Fill" Value="Blue"/>
</Trigger>
<Trigger Property="IsPressed" Value="True">
<Setter TargetName="MyEllipse" Property="Fill" Value="Red"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter TargetName="MyEllipse" Property="Fill" Value="Gray"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
If you want to reuse the style on multiple buttons, add it to a resource dictionary in scope and assign an x:Key to refer to it via StaticResource or DynamicResource.

You need to create Style of button instead Template. Button's template you can set inside style (read more about Style in WPF):
<Button x:Name="ButtonEquals"
Grid.Column="4"
Grid.Row="6"
Width="47"
Height="47"
Content="=">
<Button.Style>
<Style TargetType="Button">
<!-- Here is properties for buttons with same style-->
<Setter Property="Foreground" Value="White"/>
<Setter Property="BorderBrush" Value="{x:Null}"/>
<Setter Property="Background" Value="#FFFF9500"/>
<!-- Here is your template -->
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse Fill="{TemplateBinding Background}"/>
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<!-- Here is style triggers for interact with button -->
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<!-- Set color as you wish -->
<Setter Property="Background" Value="LightSalmon"/>
</Trigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
But actually, you need to create global ResourceDictionary (read about it) and there set styles for all buttons like <Style x:Key="CalculatorButton"> for set to buttons like <Button Content="1" Style="{StaticResource CalculatorButton}"/>

WPF changing button color, with a defined style already in place

i've made some rounded buttons, using a template. hovering the button changes the colour
MainWindow
<Button Grid.Column="1" x:Name="pressbtn" Command="{Binding TypeChange}"
CommandParameter="{Binding Name ,RelativeSource={RelativeSource Self}}"
Style="{StaticResource btnBlue}" BorderBrush="MidnightBlue"
HorizontalAlignment="Stretch">Press</Button>
Style Resource
<Style TargetType="Button" x:Key="btnBlue">
<Setter Property="Background" Value="Transparent"/>
<Setter Property="Foreground" Value="#000"/>
<Setter Property="FontSize" Value="13"/>
<Setter Property="Margin" Value="5"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="0,1,1,0"
CornerRadius="10">
<ContentPresenter HorizontalAlignment="Center"
VerticalAlignment="Center"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="MidnightBlue"/>
<Setter Property="Foreground" Value="White"/>
</Trigger>
</Style.Triggers>
</Style>
this works fine, but i'd like the button to stay on a background colour until another button is pressed, upon which it would go transparent and the other button would change colour
i have tried (where IsSelected is an integer, with each button triggering the property)
<DataTrigger Binding="{Binding IsSelected}" Value="0">
<Setter Property="Background" Value="MidnightBlue"/>
</DataTrigger>
i've also tried
<Trigger Property="IsPressed" Value="True">
<Setter Property="Background" Value="MidnightBlue"/>
<Setter Property="Foreground" Value="White"/>
</Trigger>
it seems that any of the button events (like IsPressed) are transient, so a button press works for a brief period but wont stick. reading up about the , it appears that it doesn't work because i set the Background inline in the main Setter
<Setter Property="Background" Value="Transparent"/>
However, if i take out that Property, nothing changes
this part of XAML is a weak point (Styles, Templates), and i can't find anything in searching that helps or at least that i understand very well. Any assistance in getting the <DataTrigger> or other method to work is appreciated

If you want a "sticky" version of IsPressed, you should use a ToggleButton and bind to its IsChecked property.
An ordinary Button has no property to indicate whether it has previously been clicked or not.
You will of course also have to write some code that sets the IsChecked property back to false or true when the other Button is clicked.
If IsChecked doesn't fits your requirements, there is the Tag property that you can set to anything.

Multiple styles and content on one button

I have a HomePage with a number of buttons on that I am trying to get to do a couple of things. Firstly, I have a Style in a ResourceDictionary that dictates the overall 'look and feel' of the buttons. It looks like this:
<Style TargetType="Button" x:Key="HomeButton">
<Setter Property="Foreground" Value="White"/>
<Setter Property="Background" Value="#06658D"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Border Background="{TemplateBinding Background}" BorderBrush="White" BorderThickness="1">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="Background" Value="White"/>
<Setter Property="Foreground" Value="#06658D"/>
</Trigger>
</Style.Triggers>
</Style>
Nothing too complicated, however I want the MouseOver effect to persist after being clicked. So now I am looking at doing something like this:
<Button Grid.Row="0" Style="{StaticResource HomeButton}" Content="Contacts">
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding ContactsClicked}" Value="True">
<Setter Property="Background" Value="White"/>
<Setter Property="Foreground" Value="#06658D"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button>
I'll bind the command element of the Button to set ContactsClicked = true and reset this when another button is pressed. However, I get the error saying that Content is set multiple times.
Is it possible to have an overall Style of the Button set, as well as a 'Clickedstyle and to have aTextBlockdisplaying text on the button all at once or am I approaching this wrong? I am trying to not have an individual overall style for every singleButton`as that's a lot of repeated code.
For clarity this is what I am aiming for:

I've managed to find a solution myself, instead of using a Button us a ToggleButton instead:
<Style TargetType="ToggleButton" x:Key="HomeButton">
<Setter Property="Foreground" Value="White"/>
<Setter Property="Background" Value="#06658D"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border Background="{TemplateBinding Background}" BorderBrush="White" BorderThickness="1">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Background" Value="Black" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="Background" Value="White"/>
<Setter Property="Foreground" Value="#06658D"/>
</Trigger>
<Trigger Property="IsChecked" Value="True">
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="Background" Value="White"/>
<Setter Property="Foreground" Value="#06658D"/>
</Trigger>
</Style.Triggers>
</Style>

I would add this as a comment but im not allowed.
If your goal is that the button will stay selected after it is clicked, why not use a RadioButton? A RadioButton has a built-in property called IsChecked but will also remain "Checked" or "Selected" even after multiple clicks.
Of course you can define the behavior and the styles in a similar manner, create a simple Trigger on the property IsChecked.
If more explanation is needed, just say so.

How to display validation error in button bound to command

I am developing an app and trying to stick to an MVVM model, I have a button that is just bound to a command. Currently the command can be enabled / disabled and greys out the button when the command is set to CanExecute false. But I want to add the ability to show validation errors on the button (by changing its color to red, maybe showing a tooltip).
The validation is currently already shown in another location in the UI, but the users are getting annoyed that the button is enabled and they click it only to have a message box pops up telling them they shouldn't of clicked the button because there is a validation error. But just disabling the button completely without showing them why would make the users confused(since they overlook the large red validation error at the bottom of the screen). So how can I show additional information on the save button?
This is my current button xaml:
<Button Name="SaveDataPointButton" Style="{StaticResource ImageButton}" Command="{Binding OpenDataPoint.SaveDataPointEditsCommand}" Margin="5,0" VerticalAlignment="Stretch">
<Image Source="save.png" Stretch="None" ToolTip="Save Edits"/>
</Button>
And the style that is changing its appearance when IsEnabled is false, is it possible to somehow inspect some other command state from the style to make the button red during validation errors?
<!-- Style for all of the nav and save buttons in the datapoints view -->
<Style x:Key="ImageButton" TargetType="Button">
<Setter Property="SnapsToDevicePixels" Value="true"/>
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border
x:Name="Border"
BorderThickness="0">
<ContentPresenter
Margin="2"
HorizontalAlignment="Center"
VerticalAlignment="Center"
RecognizesAccessKey="True"/>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="Border" Property="Background">
<Setter.Value>
<SolidColorBrush Color="LightGray"/>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="IsPressed" Value="true">
<Setter TargetName="Border" Property="Background">
<Setter.Value>
<SolidColorBrush Color="Gray"/>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Opacity" Value="0.3"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Command" Value="{x:Null}">
<Setter Property="IsEnabled" Value="False"/>
</Trigger>
</Style.Triggers>
</Style>

I ended up using a DataTrigger bound to another property on the view model to change the background color, but because I was setting a ControlTemplate in the style, the only way I could figure out to make the DataTrigger apply a background change was to copy the entire style and put the DataTrigger on the Border element in the control template. Since apparently you can't reference a child element from the new ControlTemplate from outside that control template.
<!-- Style for all of the nav and save buttons in the datapoints view -->
<Style x:Key="ImageSaveButton" TargetType="Button">
<Setter Property="SnapsToDevicePixels" Value="true"/>
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border
x:Name="Border"
BorderThickness="0">
<Border.Style>
<Style TargetType="Border">
<Style.Triggers>
<DataTrigger Binding="{Binding OpenDataPoint.HasValidationError}" Value="True">
<Setter Property="Background" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Style>
<ContentPresenter
Margin="2"
HorizontalAlignment="Center"
VerticalAlignment="Center"
RecognizesAccessKey="True"/>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="Border" Property="Background">
<Setter.Value>
<SolidColorBrush Color="LightGray"/>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="IsPressed" Value="true">
<Setter TargetName="Border" Property="Background">
<Setter.Value>
<SolidColorBrush Color="Gray"/>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Opacity" Value="0.3"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Command" Value="{x:Null}">
<Setter Property="IsEnabled" Value="False"/>
</Trigger>
</Style.Triggers>
</Style>

ResourceDictionary Style Triggers not working

from the following Trigger only the Foreground Setter is working. I do not understand why.
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="Red"/>
<Setter Property="BorderBrush" Value="Red"/>
<Setter Property="Foreground" Value="Red"/>
</Trigger>
Thanks for any help.

The reason this doesn't work is because the default Button template uses a ButtonChrome that draws the border and background and handles states like mouseover and disabled depending on the Windows theme (e.g. Windows XP style, Windows 7 style).
In order to allow your triggers to be applied, you will need to define a custom Button template that uses standard stylable WPF elements, like Border, instead of ButtonChrome. Here's a bare-bones working example:
<Button Content="button">
<Button.Style>
<Style TargetType="Button">
<Setter Property="BorderThickness" Value="3" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Border Background="{TemplateBinding Property=Background}"
BorderBrush="{TemplateBinding Property=BorderBrush}"
BorderThickness="{TemplateBinding Property=BorderThickness}">
<ContentPresenter />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="Red" />
<Setter Property="BorderBrush" Value="Green" />
<Setter Property="Foreground" Value="Blue" />
</Trigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>

Button in WPF has a default control template. The correct way to override the Button's default behavior is by overriding default control template. This can be done with something similar to below:
<Button Width="100" Height="50" Content="Click Me!">
<Button.Template>
<ControlTemplate TargetType="{x:Type Button}">
<Border x:Name="bdr_main" CornerRadius="20" Margin="4" BorderThickness="1" BorderBrush="Black" Background="LightGray">
<ContentPresenter VerticalAlignment="Center" HorizontalAlignment="Center" Margin="8,6,8,6" ContentSource="Content" />
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter TargetName="bdr_main" Property="Background" Value="LightGreen"/>
</Trigger>
<Trigger Property="IsPressed" Value="True">
<Setter TargetName="bdr_main" Property="Background" Value="Red"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Button.Template>
Found # http://harishasanblog.blogspot.com/2011/02/ismouseover-trigger-not-working-in-wpf.html
Hope it helps!

Try using the trigger on the controltemplate.
<ResourceDictionary>
<Style x:Key="TestButton" TargetType="Button">
<Setter Property="Height" Value="30" />
<Setter Property="Width" Value="30" />
<Setter Property="Background" Value="Transparent" />
<Setter Property="Foreground" Value="Green" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Foreground" Value="Purple" />
</Trigger>
</ControlTemplate.Triggers>
<Grid>
<Rectangle Fill="{TemplateBinding Foreground}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>