I am working on making a barchart that shows running hours. The intended display would be 3 hours and 10 minutes Using the default tooltip label would mean that this would be shown as 3.1667 hours, which isn't user friendly way of displaying the data.

Since Blazorise 1.7 it is possible to do this using the ChartTooltipCallback however I can't seem to make it work.

If I look at the class itself

Callbacks = new ChartTooltipCallbacks
{
   Label = x => "Hello world"
}

should work but I get an SystemArgumentException

Unhandled exception rendering component: The expression must return a FormattableString. (Parameter 'expression')
      System.ArgumentException: The expression must return a FormattableString. (Parameter 'expression')
         at Blazorise.Utilities.ExpressionConverter.ToTemplatedStringLiteral(LambdaExpression expression)
         at Blazorise.Utilities.Converters.<ToDictionary>g__ProcessValue|1_0(Object value, Boolean emitDefaultValue, <>c__DisplayClass1_0&)
         at Blazorise.Utilities.Converters.ToDictionary(Object source, Boolean addEmptyObjects, Boolean forceCamelCase)
         at Blazorise.Utilities.Converters.<ToDictionary>g__ProcessValue|1_0(Object value, Boolean emitDefaultValue, <>c__DisplayClass1_0&)
         at Blazorise.Utilities.Converters.ToDictionary(Object source, Boolean addEmptyObjects, Boolean forceCamelCase)
         at Blazorise.Utilities.Converters.<ToDictionary>g__ProcessValue|1_0(Object value, Boolean emitDefaultValue, <>c__DisplayClass1_0&)
         at Blazorise.Utilities.Converters.ToDictionary(Object source, Boolean addEmptyObjects, Boolean forceCamelCase)
         at Blazorise.Utilities.Converters.<ToDictionary>g__ProcessValue|1_0(Object value, Boolean emitDefaultValue, <>c__DisplayClass1_0&)
         at Blazorise.Utilities.Converters.ToDictionary(Object source, Boolean addEmptyObjects, Boolean forceCamelCase)
         at Blazorise.Charts.BaseChart`4.SetOptions(TOptions options)

I've had a look at Difference between String, FormattableString, IFormattable which explains the formattable string, but even if I change it to

Callbacks = new ChartTooltipCallbacks
{
   Label = x=> $"Hello world {x.FormattedValue}"
}

the same exception gets thrown.