Button not disabled on page load in Xamarin.Forms - xamarin

Question

I have a button in my page. I want to disable this button on page load, but its not disabled.
XAML:
<Button IsEnabled="{Binding IsEnabledSaveBtn,Mode=TwoWay}" Text="Save" Command="{Binding SaveItem}" />
ViewModel:
bool _isEnabledSaveBtn = false;
public bool IsEnabledSaveBtn
{
get { return _isEnabledSaveBtn; }
set
{
_isEnabledSaveBtn = value;
OnPropertyChanged();
}
}
Inside ViewModel Constructor:
public CreateDiscountViewModel(INavigation navigation)
{
Navigation = navigation;
IsEnabledSaveBtn=False;
}
I'm also validating data on TextChange event and it's working fine. But I want to disable this button on page load.
How can I solve this?

Answer 1

You need the following changes:
In your XAML you do not need two-way binding :
<Button IsEnabled="{Binding IsEnabledSaveBtn}" Text="Save" Command="{Binding SaveItem}" />
Your Property should look something like this:
private bool _isEnabledSaveBtn;
public bool IsEnabledSaveBtn
{
get { return _isEnabledSaveBtn; }
set
{
_isEnabledSaveBtn = value;
OnPropertyChanged(nameof(IsEnabledSaveBtn));
}
}
And in your ViewModel constructor set the value:
public CreateDiscountViewModel(INavigation navigation)
{
Navigation = navigation;
IsEnabledSaveBtn = false;
}

Answer 2

Something seems to be wrong with your OnPropertyChanged event.
Try the following, it will work.
is Button Enabled:
bool _isEnabledSaveBtn = false;
public bool IsEnabledSaveBtn
{
get { return _isEnabledSaveBtn; }
set
{
_isEnabledSaveBtn = value;
OnPropertyChanged("IsEnabledSaveBtn");
}
}
OnPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
and in your contructor
IsEnabledSaveBtn = false;