Inheriting ComboBox in WPF using C# - c#

I am deriving from Combobox to add some additional functionality, such as a checkbox.
The issue is, even with a simple implementation the Items.Add method does not work.
For example, here is the XAML:
<Style TargetType="{x:Type local:CustomControl1}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:CustomControl1}">
<ComboBox>
</ComboBox>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
The ComboBox is visible, but no information is added when I call the Items.Add method. What do I need to implement from the ComboBox class to achieve this? Do I need to do something with the popup? Add a Textblock?

That doesn't look to me like you're deriving from ComboBox... It looks to me like you're putting a ComboBox inside the ControlTemplate of your custom control.
If you are also deriving your custom control from ComboBox and calling Items.Add on your custom control, then you've basically got two lists of data (one for your custom control and one for the combobox in your controltemplate) and they are not linked in any way.
I'd suggest popping open Expression Blend and taking a look at the control template for a default ComboBox. If you want to derive from ComboBox you can then modify that controltemplate to suit your needs.

Related

Change the control property globally in wpf

I have a back button which is copied almost to all the Controls in my application.
I have set the styles and properties of the button on each individual control (usercontrol)
Now I want to change the text property of the button of all the control (usercontrol).
I don't want to go and change the property of each control.
Please help me setting a global property which sets the property in one place.
Since the style is common to all pages. Create the style without a key/name, just the target type would do.
<Style TargetType="{x:Type Button}">
Then do either of the following -
Add it to the App.XAML for visibility throughout the app
Better approach would be to define a resource dictionary file and import it, wherever you need it.
<Style TargetType="{x:Type Button}">
<Setter Property="Text" Value="{Binding text}" />
<Setter Property="...." Value="{Binding ....}"/>
</Style>
Add this to App.xaml file as you want it to be global style for all your user controls.

WPF: Which properties are applied to the ControlTemplate

I'd like to understand which properties of an xaml Control are applied to the ControlTemplate of that Control. F.e. If I create a Control based on the Window Class like this:
(This is very simplified — It doesn't make sense in the current state I know...)
public class BaseWindow : Window {
public BaseWindow() { }
}
And the Template:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:shell="clr-namespace:Microsoft.Windows.Shell;assembly=Microsoft.Windows.Shell"
xmlns:local="clr-namespace:Arctic">
<Style TargetType="{x:Type local:BaseWindow}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:BaseWindow}">
<Grid Background="Transparent">
<Border Background="{TemplateBinding Background}"/>
<ContentPresenter/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
Now, when I specify a BaseWindow Control in my app the Margin Property is applied to the BaseWindow without specifying a TemplateBinding. The Background isn't, I have to declare the TemplateBinding in the Template in order to achieve that. Can you explain to me why some properties are applied to the ControlTemplate by default and others are not?
My guess is, that the Window.xaml (Default Window Template of WPF) binds to some properties like the Margin but ignores some like Background. If that is true, then I do not understand why I can set the Background in a Window Control and it is applied to it. Seems like the Window binds to some properties and stops doing that when you derive from it…
This is probably completely wrong — I just wanted to explain my thoughts.
Window class inherit FrameworkElement and all its properties including FrameworkElement.Margin. Same goes for Control.Background. Your question is why you have to do something to have Control.Background working.
Answer is simple:
Margin is used in layouting, its functionality is implemented/provided by FrameworkElement and it happens always, invisible for you and disregarding of ControlTemplate (because all framework elements participate in layouting and use margin).
Background, in turn, is provided to be use by visuals. It's up to you how to use it, because only you know how control will looks like. Control doesn't know what to do with that property.
So, you have to use TemplateBinding to bind Background to some color in your ControlTemplate, but Margin works without need to do anything in control template.

How to work with control inheritance

I use Telerik as a WPF library. We can apply a theme on Telerik controls using application Theme (i.e. theme manager). For Microsoft controls we can set a property to make the theme apply.
The problem is : I don't want to write this line :
<Style TargetType="{x:Type CheckBox}">
<Setter Property="telerik:StyleManager.Theme" Value="{Binding Source={StaticResource Settings}, Path=Default.Theme}" />
</Style>
for every type: CheckBox, TextBlock, TextBox etc.. for maintenance purpose.
If I target <Style TargetType="{x:Type Control}"> inheritance doesn't work well.
Base class of CheckBox is Control but when I set property on every control it doesn't set property on every child of control too. Any idea how i can do this?

usercontrol (?) for WPF reusable menu

I am a beginner at WPF so please excuse me if this question is too simple :)
I have a listbox which I would like to filter by various filter conditions. This listbox I fill with instances of a particular type. Each filter condition is associated with one of the listbox items' properties. (They are like: this or that string property starts with string XXX.)
For this I would need a menu for each property from which users can select the filter conditions they want to filter the items with. Each property of the same type will have the very same set of menu items with the various filter conditions. (For strings: starts with, ends with... for ints: lower than, higher than, etc.)
The menus require some code behind too so I don't want to program these for each property separately.
My problem is that I don't know in what way could I program these. I cannot program them as UserControls because all what I need is MenuItems in a Menu. But I cannot program them as MenuItem derived classes because I would need the XAML for designing them for each type. Could I create a MenuItem derived class with a XAML somehow? Or do you have any other suggestions?
In WPF, we work with data elements whose public properties are data bound to the properties of various UI controls via DataTemplates. Please see the Data Templating Overview page on MSDN for the full story.
In order to do this, we develop custom classes that contain all of the necessary properties that we need to display and then we declare one or more DataTemplates that define the binding connections between the classes and the UI controls, or MenuItems in your case.
The benefit of this is that in order to display a Menu in the UI, you just need to data bind one of your custom menu class objects to a control in the UI and let the DataTemplate do the rest. So if you want to change the menu contents, you just need to change the data item that is data bound to the Menu.
So to answer your question directly, a Menu control would be most suitable for you to use, but you don't store the Menu properties in your code behind... you store the property values in your custom classes that will be data bound to the Menu control properties:
<Menu ItemsSource="{Binding CollectionOfYourCustomClassItems}" ... />
It is worth pointing out that you may need to set the child MenuItem properties in a Style and not a DataTemplate as usual (taken from the accepted answer to the WPF MenuItem : Mix databound items and static content question (which I recommend that you read) here on Stack Overflow):
<MenuItem Header="_Recent Files" ItemsSource="{Binding Commands,Mode=OneWay}">
<MenuItem.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Header" Value="{Binding Path=ShortName}" />
<Setter Property="ToolTip" Value="{Binding Path=FileName}" />
<Setter Property="Command" Value="{Binding Path=OpenCommand}" />
<Setter Property="CommandParameter" Value="{Binding Path=OpenParameter}" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=IsSeparator}" Value="true">
<Setter Property="MenuItem.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type MenuItem}">
<Separator Style="{DynamicResource {x:Static MenuItem.SeparatorStyleKey}}"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</MenuItem.ItemContainerStyle>
</MenuItem>
You will find many more tutorials and related questions regarding data binding to MenuItems online, so I won't go over everything again here. Please see the following article to start with:
Binding menus using HeirarchicalDataTemplates

Styling a selected ListViewItem in Windows 8 CP

I want to change the appearance of the Border of the selected Item in the picture linked below.
I've already been looking around on msdn.com and on the internet, but I've found nothing useful.
How can I do this?
The selection appearance is part of the ControlTemplate for ListViewItem. To modify the template for an entire ListView use the ItemContainerStyle to apply a Style to each item, which can contain a modified version of the template.
<ListView>
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListViewItem">
...
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListView.ItemContainerStyle>
</ListView>
The default template for ListViewItem is pretty complex so in order to preserve as much of the default behavior as possible and give you a good starting point, it's easiest to use Blend to create a copy for you.
In Blend, right-click your ListView and select:
Edit Additional Templates -> Edit Generated Item Container -> Edit A Copy...
and it will create a Style for you in the form above with the default template filled in. The selection appearance uses a few different elements in the template which you may want to modify - these can be seen by selecting the Selected state in the States panel in Blend and drilling into the highlighted items in the Objects panel.
I've found out another solution that might be helpful for others: override specific brush resources in App.xaml. It works without cloning any default style, and is just as simple as:
<SolidColorBrush x:Key="ListViewItemSelectedBackgroundThemeBrush" Color="myColor1"/>
<SolidColorBrush x:Key="ListViewItemPointerOverBackgroundThemeBrush" Color="myColor2"/>
Of course, there are more bushes that can be overriden, and a list of them can be found here: ListViewItem styles and templates.
Note that this approach changes the appearance for ALL ListViews in the application.

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