dataviz: was a common xml namespace alias used to display silverlight toolkit object names. This was for Silverlight 3 at a time when libraries could not define their own XML namespaces.
.NET. System.Windows.Controls.DataVisualization dataviz : -
xmlns:dataviz="clr-namespace:System.Windows.Controls.DataVisualization;assembly=System.Windows.Controls.DataVisualization.Toolkit"
xmlns:charting="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit"
Silverlight 4 URL- .NET, : -
xmlns:toolkit="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit"
xmlns , , , Xaml ( ). - , Silverlight 4 , , .