Line Charts

To display a line chart, use the Chart control and add a LineSeries to the chart. The LineSeries must specify an ItemsSource, which is a collection containing the data to be displayed, and will normally specify a XBinding and a YBinding, which are data bindings specifying how the points along the line are determined from the data.
CopyCreating a line chart
<ms:Chart Title="Sales" Width="600" Height="400">
  <ms:LineSeries ItemsSource="{Binding}" 
                 XBinding="{Binding Quarter}" 
                 YBinding="{Binding Amount}" 
                 />
</ms:Chart>

If the ItemsSource contains a collection of Point objects, you can omit the XBinding and YBinding.
 

To change the color of the line, use the SeriesBrush property:

CopySetting the line color
<ms:LineSeries SeriesBrush="Red" />

To show a dashed line, use the DashArray property. The XAML syntax for DashArray is the same as for Shape.StrokeDashArray—see the Silverlight SDK documentation for details.

CopyShowing a dashed line
<ms:LineSeries DashArray="2 1" />

To make broader changes to the appearance of the line, use the LineStyle property. The target type for the LineStyle should be Path.

CopySetting the line style
<ms:LineSeries>
  <ms:LineSeries.LineStyle>
    <Style TargetType="Path">
      <Setter Property="StrokeThickness" Value="4" />
      <Setter Property="Stroke" Value="Red" />
      <Setter Property="StrokeDashArray" Value="2 1" />
    </Style>
  </ms:LineSeries.LineStyle>
</ms:LineSeries>

You can optionally show a symbol at each point on the line by setting the SymbolStyle property. The target type of the SymbolStyle should be ChartSymbol, and to change the shape of the point you must set the control Template.

CopyDisplaying a square at each point of the line
<ms:LineSeries>
  <ms:LineSeries.SymbolStyle>
    <Style TargetType="ms:ChartSymbol">
      <Setter Property="Width" Value="8" />
      <Setter Property="Height" Value="8" />
      <Setter Property="Margin" Value="-4,-4,4,4" />
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="ms:ChartSymbol">
            <Rectangle Stroke="Red" 
                       StrokeThickness="1" 
                       Fill="Pink" 
                       />
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
  </ms:LineSeries.SymbolStyle>
</ms:LineSeries>

The template origin is the location of the data point. If you want your shape to be centred on the data point, set negative left and top margins equal to half the width and height respectively.
 

Area Charts

To display an area chart, add a AreaSeries to a Chart control.

Area series have the same options as line series and are drawn in the same way, except that the area between the line and the X axis is filled with the SeriesBrush. To make multiple overlapping area series visible, the fill is made slightly transparent. To make the fill opaque, or to otherwise customise the appearance of the filled area, use the AreaStyle property. The target type for the AreaStyle should be Path.

CopyAll glory to the hypnotoad
<ms:AreaSeries ItemsSource="{Binding}" 
               XBinding="{Binding Quarter}" 
               YBinding="{Binding Amount}" 
               >
  <ms:AreaSeries.AreaStyle>
    <Style TargetType="Path">
      <Setter Property="Fill">
        <Setter.Value>
          <RadialGradientBrush SpreadMethod="Repeat">
            <GradientStop Offset="0" Color="Blue" />
            <GradientStop Offset="0.2" Color="Purple" />
            <GradientStop Offset="0.4" Color="Red" />
            <GradientStop Offset="0.6" Color="Yellow" />
            <GradientStop Offset="0.8" Color="Lime" />
            <GradientStop Offset="1" Color="Blue" />
          </RadialGradientBrush>
        </Setter.Value>
      </Setter>
    </Style>
  </ms:AreaSeries.AreaStyle>
</ms:AreaSeries>

In the absence of LineStyle and AreaStyle, the SeriesBrush is used to draw the line and the fill, but these elements are drawn separately. Using a brush other than a SolidColorBrush for the SeriesBrush may not produce the expected visual effect.