add dyanmicly UIelement into stackpanel defined in dataTemplate

Question

hello everybody, i m looking for to add dynamically a user interface element inside my stack panel here 's my code

    <DataTemplate x:Name="Mydt" >
        <Border Name="border" Padding="5" Margin="5">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
                <StackPanel Orientation="Horizontal" Name="mystack">
                    <TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding q_LabelFR}"/>
                    <TextBox Grid.Row="0" Grid.Column="3" Margin="50,0,0,0" Text="{Binding q_Type}" />

                </StackPanel>
            </Grid>
        </Border>

    </DataTemplate>

Thank you very match for helping