Adding Rows To data grid View in WPF 4.0 in already created column

See more:

C#

C#4.0

I have a datagrid of three columns and I want to add the values for it's rows manually, I want to add these values to it's row:
String Name = "Yasser";
double degree = 98 ;
string Class = "A1";

and this is the XML

<datagrid itemssource="Binding" name="dg_Test" width="Auto" height="312" autogeneratecolumns="&"True"" verticalalignment="Top" horizontalalignment="Stretch" headersvisibility="All" canuserreordercolumns="True" canuserresizecolumns="True">
                          CanUserSortColumns="True"  HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden" BorderBrush="Gray" BorderThickness="2" HorizontalGridLinesBrush="Red" VerticalGridLinesBrush="Red"
                          AlternationCount="2" AreRowDetailsFrozen="False" CanUserResizeRows="False" RowDetailsVisibilityMode="Visible" RowHeight="20" SelectionMode="Single" FlowDirection="RightToLeft" Margin="0,36,0,0" Grid.RowSpan="2" CanUserAddRows=vTrue" CanUserDeleteRows="True"
            <DataGrid.Columns">
                <DataGridTextColumn Header="Student Name" Width="200" </DataGridTextColumn>
                <DataGridTextColumn Header="Student Grade" Width="200" </DataGridTextColumn>
                <DataGridTextColumn Header="Student Class" Width="200" </DataGridTextColumn>
        </DataGrid.column>
</DataGrid></datagrid>