WPF Child control, style only content part

Question

I have created a custom control called "Field", that inherits from ContentControl and that contains a Grid and a label to expose the field label, and a ContentPresenter to allow to put a control depending on the data we want to edit.

Then I created a custom control called "TextField", that inherits from Field, that should put a TextBox into the Content.

Here are the styles in Generic.xaml :

<Style TargetType="{x:Type controls:Field}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type controls:Field}">
                <Border Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}">
                    <Grid x:Name="grd" Margin="3px">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="{Binding Path=LabelLength, RelativeSource={RelativeSource AncestorType=Control}}" />
                            <ColumnDefinition Width="{Binding Path=ContentLength, RelativeSource={RelativeSource AncestorType=Control}}" />
                        </Grid.ColumnDefinitions>
                        <Label Grid.Column="0" Content="{Binding Path=Label, RelativeSource={RelativeSource AncestorType=Control}}" />
                        <ContentPresenter Grid.Column="1" Content="{TemplateBinding Content}" Margin="{TemplateBinding Padding}" />
                    </Grid>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Style TargetType="{x:Type controls:FieldText}" BasedOn="{StaticResource {x:Type controls:Field}}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type controls:FieldText}">
                <TextBox Grid.Column="1" MaxLines="1" TextWrapping="NoWrap" />
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

By evidence, this shows only a textbox when using a TextField. But how could I just style the content (eg the TextBox in this example) by keeping the rest of the control inheriting the parent style?

I know I could rewrite the whole control for each derivated control, but that's against the inheritence principles, no? Would mean duplicated code (duplicated markup here) and if I change anything in the parent "Field" I would have to change it in every child control, with the risk of errors...

You are saying yourself about putting TextBox into Content, but then you put that into Template overwriting everything. — Evk, Mar 07 '17 at 10:20

score 0 · Answer 1 · edited May 23 '17 at 12:17

Set the Content property of the parent control to an instance of a TextBox that you can style however you want:

<controls:Field Background="Gray">
    <TextBox Grid.Column="1" MaxLines="1" TextWrapping="NoWrap" />
</controls:Field>

This is how a ContentControl is supposed to be used.

You cannot override only a part of a ControlTemplate:

WPF: Is there a way to override part of a ControlTemplate without redefining the whole style?

WPF Child control, style only content part

1 Answers1