Filter Transformation

This article contains example code that shows the usage of the FilterTransformation component.

Note

Instead of the FilterTransformation, you can also use Linking with different Predicates to achieve the same behaviour. Read more about linking with predicates

Filter with POCO

This example shows how to filter data in a data flow with a strongly typed objects

public class MyRow
{
    public int Id { get; set; }
    public string Value { get; set; }
}

public void ExampleFilterPoco() {
    var source = new MemorySource<MyRow>();
    source.DataAsList.Add(new MyRow() { Id = 1, Value = "Test1" });
    source.DataAsList.Add(new MyRow() { Id = 2, Value = "Test2" });
    source.DataAsList.Add(new MyRow() { Id = 3, Value = "Test3" });

    var filter = new FilterTransformation<MyRow>();
    filter.FilterPredicate = row => {
        return row.Id == 2;
    };

    var dest = new MemoryDestination<MyRow>();

    source.LinkTo(filter).LinkTo(dest);

    Network.Execute(source);

    foreach (var row in dest.Data)
        Console.WriteLine($"Id:{row.Id} Value:{row.Value}");

    //Outputs
    //Id:1 Value:Test1
    //Id:3 Value:Test3
}

Filter with Predicate linking

This example has the same effect as the previous code, but now we are using predicates in the LinkTo methods.

var source = new MemorySource<MyRow>();
source.DataAsList.Add(new MyRow() { Id = 1, Value = "Test1" });
source.DataAsList.Add(new MyRow() { Id = 2, Value = "Test2" });
source.DataAsList.Add(new MyRow() { Id = 3, Value = "Test3" });

var dest = new MemoryDestination<MyRow>();
var voidDest = new VoidDestination<MyRow>();

source.LinkTo(dest, row => row.Id != 2);
source.LinkTo(voidDest, row => row.Id == 2);

Network.Execute(source);

foreach (var row in dest.Data)
    Console.WriteLine($"Id:{row.Id} Value:{row.Value}");

//Outputs
//Id:1 Value:Test1
//Id:3 Value:Test3

/* Delete below here */
Assert.Collection(dest.Data,
    r => Assert.True(r.Id == 1 && r.Value == "Test1"),
    r => Assert.True(r.Id == 3 && r.Value == "Test3")
    );

Predicate linking with implicit void

This example shows how the third parameter of the LinkTo method can be used to discard unwanted records.

public void ExampleFilterLinkingWithPredicateAndImplicitVoid() {
    var source = new MemorySource<MyRow>();
    source.DataAsList.Add(new MyRow() { Id = 1, Value = "Test1" });
    source.DataAsList.Add(new MyRow() { Id = 2, Value = "Test2" });
    source.DataAsList.Add(new MyRow() { Id = 3, Value = "Test3" });

    var dest = new MemoryDestination<MyRow>();

    source.LinkTo(dest, row => row.Id != 2, row => row.Id == 2);

    Network.Execute(source);

    foreach (var row in dest.Data)
        Console.WriteLine($"Id:{row.Id} Value:{row.Value}");

    //Outputs
    //Id:1 Value:Test1
    //Id:3 Value:Test3
}