How to pass value from xamarin page to ivalueconverter class properties Xamarin Forms-CodePudding

I have a class of IValueConverter with a property named myValue which I want to divide the ivalueconverter by its property myValue! But, I want to know if it is possible to pass the myValue from xamarin page to ivalueconverter? If yes, how?

IvalueConverter

class salesUIbtnWidth : IValueConverter
{
    public double myValue { get; set; }
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return (double)value / myValue;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Try Implementing the class

 <Button Text="Click me" HorizontalOptions="Center" VerticalOptions="Center"
         CornerRadius="15" WidthRequest="{Binding Source={x:Reference 
         frame}, Path=Width,Converter={StaticResource salesUIbtnWidth}}">
 </Button>//how to bind also the MyValue

All I want is to know how to set myValue in page and pass it to (IvalueConverter) from xamarin during runtime!!

CodePudding user response：

You can pass the value by ConverterParameter.

You can refer to the sample code:

<Label Text="{Binding Red,
                  Converter={StaticResource doubleToInt},
                  ConverterParameter=255,
                  StringFormat='Red = {0:X2}'}" />


 <local:DoubleToIntConverter x:Key="doubleToInt" />

DoubleToIntConverter.cs

public class DoubleToIntConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return (int)Math.Round((double)value * GetParameter(parameter));
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return (int)value / GetParameter(parameter);
    }

    double GetParameter(object parameter)
    {
        if (parameter is double)
            return (double)parameter;

        else if (parameter is int)
            return (int)parameter;

        else if (parameter is string)
            return double.Parse((string)parameter);

        return 1;
    }
}

For more, you can check: Binding Converter Parameters

CodePudding user response：

If you don't want to use parameter, you can define MyValue when you create the converter.

<ContentPage.Resources>
    <app1:MyConverter x:Key="myConverter" MyValue="255"/>
</ContentPage.Resources>