BINDING DOES NOT RECOGNIZE TYPE

Hello,

Please change the Int64 to long for your property.

public static readonly BindableProperty Amount64Property = BindableProperty.Create(
     propertyName: nameof(Amount64),
     returnType: typeof(long),
     declaringType: typeof(NewContent1),
     defaultValue: default(long)
);
 
 
public long Amount64
{
     get => (long)GetValue(Amount64Property);
     set => SetValue(Amount64Property, value);
}

If you want to convert long to Int64, you can set convert it directly like following code. In C#, long and Int64 are the same. Long is a C# keyword, and Int64 is a structure in the .NET System namespace, both of which represent 64-bit signed integer types.

long myLong = 123456789L;
Int64 myInt64 = myLong; 

Best Regards,

Leon Lu

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I thought I was getting the same problem as Giorgio, I had a bool property in a custom control declared like this:

public BindableProperty IsCheckedProperty;
public bool IsChecked
{
    get => (bool)GetValue(IsCheckedProperty);
    set => SetValue(IsCheckedProperty, value);
}

Then instantiated in the constructor:

IsCheckedProperty = BindableProperty.Create(nameof(IsChecked), typeof(bool?), typeof(CheckmarkButton));

I could use this property in XAML as long as I was setting it with a static value like this:

IsChecked="true"

As soon as I tried to set it with a binding it would generate the error above. The fix is to declare the BindableProperty correctly as a static readonly property, instantiating it on the same line:

public static readonly BindableProperty IsCheckedProperty = BindableProperty.Create(nameof(IsChecked), typeof(bool), typeof(CheckmarkButton));