title: WPF DataGrid : Set Width of Columns to occupy all space dynamically Issue
body: <p>I have a case where I have to show data in Datagrid. Cols of DataGrid may vary from 2 to 20, I add cols dynamically. I just want to set the width of cols to "*<em>" and make it utilize all available space on the screen. But as I am adding cols dynamically, I can't assign "</em>" to the width in code. I tried with Auto, but no difference. What can be done to achieve the goal ? My XML :</p>
  
  <pre><code>           &lt;DataGrid AutoGenerateColumns="False" HorizontalAlignment="Stretch"  Margin="20,0,0,0"  x:Name="outputGrid" VerticalAlignment="Top"  HorizontalScrollBarVisibility="Visible"
                  VerticalScrollBarVisibility="Visible" BorderBrush="#FFB7B39D" Background="LightYellow" RowBackground="LightGray" AlternatingRowBackground="#FFFFFFF5" BorderThickness="2" 
                  CanUserReorderColumns="False" CanUserSortColumns="False" FontSize="13" MinWidth="675"
                  IsReadOnly="True" ColumnWidth="*"
                  ColumnHeaderStyle="{DynamicResource ColumnHeaderStyle}" ClipboardCopyMode="IncludeHeader" Foreground="Black"    &gt;
                  &lt;DataGrid.RowHeaderStyle&gt;
                      &lt;Style TargetType="DataGridRowHeader"&gt;
                          &lt;Setter Property="Content" Value="{Binding Title}" /&gt;
                      &lt;/Style&gt;
                  &lt;/DataGrid.RowHeaderStyle&gt;
  
              &lt;/DataGrid&gt;
  </code></pre>
  
  <p>Code that adds cols :</p>
  
  <pre><code>            foreach (Step2Model sm in xlsImpExp.Step2InfoDataModel.Step2ModelList)
          {
              DataGridTextColumn column = new DataGridTextColumn();
              column.Header = sm.LayerName;
              column.Width = DataGridLength.Auto;
              column.Binding = new Binding("Lay" + i + "Vol");
              outputGrid.Columns.Add(column);
              i++;
          }
  </code></pre>
  
  <p>How do I make sure that it utilize all space that is free on right side of the screen ? 
  I searched a lot on this problem, but couldn't find any solution. Any help is highly appreciated.</p>
  
  <p>Thanks</p>