This can be done using System.Windows.Markup.MarkupExtension (docs).

This will allow you pass values to the converter which could be used as arguments or return values, for example:

public class CustomNullToVisibilityConverter : MarkupExtension, IValueConverter
{
    public object NullValue { get; set; }
    public object NotNullValue { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null) return NullValue;

        return NotNullValue;
    }

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

Usage:

...
Visibility="{Binding Property, Converter={cnv:CustomNullToVisibilityConverter NotNullValue=Visible, NullValue=Collapsed}}" />
...

Be sure to reference the namespace of the converter in the .xaml.

This can be done using System.Windows.Markup.MarkupExtension (docs).

This will allow you pass values to the converter which could be used as arguments or return values, for example:

public class CustomNullToVisibilityConverter : MarkupExtension, IValueConverter
{
    public object NullValue { get; set; }
    public object NotNullValue { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null) return NullValue;

        return NotNullValue;
    }

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

Usage:

...
Visibility="{Binding Property, 
 Converter={cnv:CustomNullToVisibilityConverter NotNullValue=Visible, NullValue=Collapsed}}"  
/>
...

Be sure to reference the namespace of the converter in the .xaml.

This can be done using System.Windows.Markup.MarkupExtension (docs).

This will allow you pass values to the converter which could be used as parameters or return values, for example:

public class CustomNullToVisibilityConverter : MarkupExtension, IValueConverter
{
    public object NullValue { get; set; }
    public object NotNullValue { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null) return NullValue;

        return NotNullValue;
    }

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

Usage:

...
Visibility="{Binding Property, Converter={cnv:CustomNullToVisibilityConverter NotNullValue=Visible, NullValue=Collapsed}}" />
...

Be sure to reference the namespace of the converter in the .xaml.

This can be done using System.Windows.Markup.MarkupExtension (docs).

This will allow you pass values to the converter which could be used as arguments or return values, for example:

public class CustomNullToVisibilityConverter : MarkupExtension, IValueConverter
{
    public object NullValue { get; set; }
    public object NotNullValue { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null) return NullValue;

        return NotNullValue;
    }

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

Usage:

...
Visibility="{Binding Property, Converter={cnv:CustomNullToVisibilityConverter NotNullValue=Visible, NullValue=Collapsed}}" />
...

Be sure to reference the namespace of the converter in the .xaml.