title: Silverlight 4 DataGrid border around a column
body: <p>I haven't been able to find anyway to dynamically add a border around a column in a silverlight datagrid. Here is my xaml of my datagrid:</p>
  
  <pre><code>&lt;sdk:DataGrid x:Name="PlannedAndBookedMonthlyTable" ItemsSource="{Binding}" AutoGenerateColumns="False" Margin="5,0,5,5"&gt;
     &lt;sdk:DataGrid.Columns&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderName" Header="" Binding="{Binding SeriesName}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderJan" Header="Jan" Binding="{Binding JanValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderFeb" Header="Feb" Binding="{Binding FebValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderMar" Header="Mar" Binding="{Binding MarValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderApr" Header="Apr" Binding="{Binding AprValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderMay" Header="May" Binding="{Binding MayValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderJun" Header="Jun" Binding="{Binding JunValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderJul" Header="Jul" Binding="{Binding JulValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderAug" Header="Aug" Binding="{Binding AugValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderSep" Header="Sep" Binding="{Binding SepValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderOct" Header="Oct" Binding="{Binding OctValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderNov" Header="Nov" Binding="{Binding NovValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderDec" Header="Dec" Binding="{Binding DecValue}" /&gt;
        &lt;sdk:DataGridTextColumn x:Name="MonthlyHeaderTotal" Header="Total" Binding="{Binding Total}" /&gt;
     &lt;/sdk:DataGrid.Columns&gt;
  &lt;/sdk:DataGrid&gt;
  </code></pre>
  
  <p>This is the effect that I want to accomplish:</p>
  
  <p><img src="https://i.stack.imgur.com/rsFta.png" alt="alt text"></p>
  
  <p>How do I set the border on a column of data that depends on what current calendar month it is? </p>