CODEWITHSUNDEEP
xamarin.forms
henda79
henda79

Reputation: 535

Need a Null value from Xamarin Entry Control when Empty

It seems when using a Entry control in Xamarin forms if its not touched then it returns Null. However, if the user enters anything then clears the control, it returns string.Empty

Ideally I want to just keep the Null value as these go into the Database and as you can imagine its not very consistent with Nulls and empty strings.

What is the best way to achieve the goal of keeping the Null regardless if the control has been edited ?

I've considered Converters but this means adding them to all Entry controls, maybe doing something in the Data Access Layer... not sure what as wouldn't this mean extra code for all the properties.

Upvotes: 0

Views: 1195

Answers (2)

henda79
henda79

Reputation: 535

I actually ended up making a very simple custom control as since I required this function for all Entry controls it made no sense adding Behaviors to each one.

public class EntryEx : Entry
{
    protected override void OnTextChanged(string oldValue, string newValue)
    {
        base.OnTextChanged(oldValue, newValue == string.Empty ? null : newValue);
    }
}

Thanks to Jason for the idea.

Upvotes: 0

Shubham Tyagi
Shubham Tyagi

Reputation: 838

You can use behavior.

Code

public class EntryNullBehavior : Behavior<Entry>
{
    protected override void OnAttachedTo(Entry entry)
    {
        entry.TextChanged += OnEntryTextChanged;
        base.OnAttachedTo(entry);
    }

    protected override void OnDetachingFrom(Entry entry)
    {
        entry.TextChanged -= OnEntryTextChanged;
        base.OnDetachingFrom(entry);
    }

    void OnEntryTextChanged(object sender, TextChangedEventArgs args)
    {
        if (sender is Entry entry)
        {
            if (args.NewTextValue != null && args.NewTextValue.Equals(string.Empty))
            {
                entry.Text = null;
            }
        }
    }
}

Usgae in Xaml

xmlns:behavior="clr-namespace:DummyTestApp.Behavior"
...
<Entry x:Name="MyNullEntry" HeightRequest="50" FontSize="Large">
    <Entry.Behaviors>
        <behavior:EntryNullBehavior/>
    </Entry.Behaviors>
</Entry>

P.S. Now I don't know what you consider overkill (seeing your comment) but this solution is elegant

Upvotes: 2

Related Questions