Xamarin: Hide the button if condition is false - xamarin.forms

Question

I am new to Xamarin Forms.
I want to know how to hide a button if a specific condition is false.
ex: I need to hide the submit button until the text field has a value.
(if the text field is null, cannot click the submit button)
this is my .xaml code
<Entry Grid.Row="0"
Margin="10,10,10,20"
x:Name="ground_area"
Grid.Column="1"
MaxLength="5"
HorizontalOptions="Center"
Placeholder="area"
FontSize="18"/>
<Button x:Name="avg_nut"
Text="Submit"
Grid.Row="5"
VerticalOptions="Center"
Margin="40,0,20,50"
Style="{StaticResource buttonStyle}"
Clicked="submit_click">
</Button>

Answer 1

Hey you can use the property of the button IsEnabled="{Binding booleanProperty}" and in your view model you can manipulate the value of this property depending in what you want
I recommended you to use View Model instead of Code Behind is not that hard learn how works MVVM (Model View ViewModel)
That's my advice.
I hope this can solve your problem

Answer 2

Use Trigger:
<Entry x:Name="ground_area"/>
<Button Text="Submit">
<Button.Triggers>
<DataTrigger TargetType="Button" Binding="{Binding Text.Length, Source={Reference ground_area}, FallbackValue=0}" Value="0">
<Setter Property="IsVisible" Value="False"/>
</DataTrigger>
</Button.Triggers>
</Button>
Also, check IsEnabled property, it's better than hiding the control.