Question

I’ve got a property which is a database data type (char, DateTime, int, float etc…) and I want to change the control used to enter a value of the selected type. So for text values I want a TextBox and for date values I want a DatePicker.

One way I thought about doing it was to have one of each control on my form and set their Visibility using an appropriate IValueConverter implementation. I know this will work, but it would create a lot of code and doesn’t feel very nice.

The other way I thought was to use a ContentPresenter and set its content with a Style and DataTriggers but I can’t get it to work.

<Style x:Key="TypedValueHelper" TargetType="{x:Type ContentPresenter}">
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=DataType}" Value="Char">
            <Setter Property="Content" Value="???"/>
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=DataType}" Value="Date">
            <Setter Property="Content" Value="???"/>
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=DataType}" Value="Integer">
            <Setter Property="Content" Value="???"/>
        </DataTrigger>
    </Style.Triggers>
</Style>

If anyone can fill in my “???” or offer a better solution please do.

Answer 1

You could do a combination of style with setters and DataTemplates. You basically have the start for it in your code, although I don’t think ContentPresenter is the right control to style, since it does not have a template.

Create a style like this:

<Style x:Key="TypedValueHelper" TargetType="{x:Type ContentControl}">
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=DataType}" Value="Char">
            <Setter Property="ContentTemplate">
                <Setter.Value>
                    <DataTemplate>
                        <TextBox Text="{Binding Path=.}" />
                    </DataTemplate>
                </Setter.Value>
            </Setter>
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=DataType}" Value="Integer">
            <Setter Property="ContentTemplate">
                <Setter.Value>
                    <DataTemplate>
                        <Slider Maximum="100" Minimum="0" Value="{Binding Path=.}"
                                         Orientation="Horizontal" />
                    </DataTemplate>
                </Setter.Value>
            </Setter>
        </DataTrigger>
    </Style.Triggers>
</Style>

Then use the style in the ContentControl:

<ContentControl Content="{Binding MyValue}"
                        Style="{StaticResource TypedValueHelper}">