# Formatter Provider

This help topic will give an overview on the Formatter Provider feature of RadTimeBar.

## Using Formatter Providers

RadTimeBar provides means for customizing the interval formats through the `FormatterProvider` property of the `IntervalBase` class. Using it, you can specify different formats for each interval. To define a formatter provider, create a class that implements the `IIntervalFormatterProvider` interface.

## The IIntervalFormatterProvider interface

A formatter provider is a class that implements the `IIntervalFormatterProvider` interface. This interface has two methods that need to be implemented - `GetFormatters` and `GetIntervalSpanFormatters`. They both have to return a Func\<DateTime, string>\[] - an array of functions each of which given a DateTime value returns it as formatted string.

* `GetFormatters`—Used in the default scenario when Interval.CurrentIntervalSpan = 1, i.e. there is a period control for every interval item.
* `GetIntervalSpanFormatters`—Used when one period control corresponds to a couple of interval items. E.g. an HourInterval with CurrentIntervalSpan = 12 interval span will create two hour intervals per each day - (0:00 - 12:00) and (12:00 - 0:00). An appropriate format would be String.Format("{0} - {1}", currentIntevalString, nextIntervalString).

The following sample shows an implementation of a custom hour formatter provider and how to set it:

#### **Creating a custom formatter provider**

```C#
public class HourFormatterProvider : IIntervalFormatterProvider
{
	private static Func<DateTime, string>[] formatters;
	private Func<DateTime, string>[] intervalSpanFormatters;

	static HourFormatterProvider()
	{
		formatters = new Func<DateTime, string>[]
		{
			date => date.ToString("H:mm"),
			date => date.ToString("HH")
		};
	}

	public Func<DateTime, string>[] GetFormatters(IntervalBase interval)
	{
		return formatters;
	}

	public Func<DateTime, string>[] GetIntervalSpanFormatters(IntervalBase interval)
	{
		if (this.intervalSpanFormatters == null)
		{
			this.intervalSpanFormatters = new Func<DateTime, string>[]
			{
				date => String.Format("{0} - {1}", date.ToString("dddd H:mm"), interval.IncrementByCurrentInterval(date).ToString("H:mm"))
			};
		}

		return this.intervalSpanFormatters;
	}
}
```

#### **Setting the custom formatter provider**

```XAML
<telerik:RadTimeBar x:Name="timeBar">
	<telerik:RadTimeBar.Resources>
		<local:HourFormatterProvider x:Key="HourFormatterProvider"/>
	</telerik:RadTimeBar.Resources>
	<telerik:RadTimeBar.Intervals>
		<telerikDataVisualization:HourInterval FormatterProvider="{StaticResource HourFormatterProvider}"/>
	</telerik:RadTimeBar.Intervals>
    </telerik:RadTimeBar>
```

**RadTimeBar with a custom formatter provider for the HourInterval**

![RadTimeBar with a custom formatter provider for the HourInterval](https://www.telerik.com/winui/documentation/assets/ea3905c82e62e7c8feadde9a283969df/radtimebar-formatter-providers-0.png)