The custom filtering is based on four different xaml parts:
- Input field
- EvalExpression
- List filter
- List control
With this Filter, we can filter dynamically without using any evaluate button or something, you just input a value that you want to filter with and it will directly output you any item that contains the filter input.
Input field
The input field is just a basic Textbox/Entry we will use to input the filter criteria value.
It will look like this:
UWP
Xamarin
EvalExpression
With this EvalExpression, we can combine the Input text field with the value parameter (property from the item we want to filter).
Here is the final XAML EvalExpression solution:
UWP
Context="{Binding}"
Expression="FC1">
<controls:EvalExpressionParameter Name="FC1"
Value="{Binding ElementName=InputTextboxName, Path=Text, Converter={StaticResource StringFormatConverter}, ConverterParameter='Item.Values["NAME"].ToLower().Contains("{0}".ToLower())==true'}" />
</controls:EvalExpression>
Xamarin
<controls:EvalExpressionParameter Name="P0" Value="{Binding Path=Text, Source={x:Reference Filter_Input}, Converter={StaticResource Formatter}, ConverterParameter='Item.Values["NAME"].ToLower().Contains("{0}".ToLower())==true'}" />
<controls:EvalExpressionParameter Name="P1" Value="{Binding Path=Text, Source={x:Reference Filter_Input}}" />
</controls:EvalExpression>
The best solution would be to place this eval expression into the <Grid.Resources>.
Used namespace:
UWP
Xamarin
List filter
To get used to this EvalExpression we also need to configure a List filter component like in this case ListCollectionView for UWP & Content filtering for Xamarin:
UWP
Expression="{Binding ElementName=FilterExpression, Path=Result}"
ItemsSource="{Binding Children.Items}" />
Xamarin
Expression="{Binding Path=Result, Source={StaticResource FilterExpression}}"
ItemsSource="{Binding Children.Items}" />
Used namespace:
UWP
Xamarin
List control
The ListView is for using/displaying filtered results.
UWP
x:Name="FilterQueryList"
ItemsSource="{StaticResource FilterView}" />
Xamarin
x:Name="FilterQueryResultList"
ItemsSource="{Binding DisplayItems, Source={StaticResource FilterView}}" />
Used namespace: