WPF

<Grid Name="GrdParams" >
<TextBlock Grid.Column="0" Grid.Row="0" Text="Frequency"  VerticalAlignment="Center" />
<Slider Grid.Column="1" Grid.Row="0" Minimum="0" Maximum="0.25" SmallChange="0.001" Value="{Binding Mode=TwoWay, Path=Frequency}" ValueChanged="FreqSlider_ValueChanged" />
<TextBlock Name="TxtFreq" Grid.Column="2" Grid.Row="0" />
</Grid>

private void FreqSlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
    if (this.TxtFreq != null)
    {
        this.TxtFreq.Text = (sender as Slider).Value.ToString("###0.####");
    }
}

Paul Selormey wrote:

How can I render this on a canvas of the main thread after the background thread is completed?

Mark Salsbery
Microsoft MVP - Visual C++

<DataTemplate x:Key="Column3">
    <Border BorderThickness="0,0,1,0" BorderBrush="Gray" Margin="-6,0,-6,0">
        <TextBlock Margin="2,1,1,1" Text="{Binding Path=stand_name}"></TextBlock>
    </Border>
</DataTemplate>
<DataTemplate x:Key="Column3_Alternative">
    <Border BorderThickness="0,0,0,0" BorderBrush="Gray" Margin="-6,0,-6,0">
        <TextBlock Margin="2,1,1,1" Text="{Binding Path=stand_name}"></TextBlock>
    </Border>
</DataTemplate>

DataTemplate dt = lstvTCKeyValue.FindResource("Column3_Alternative") as DataTemplate;
lstvTCKeyValue.ItemTemplate = dt;

<DataTemplate x:Key="Column3_ShowStandColumn">
    <Border BorderThickness="0,0,1,0" BorderBrush="Gray" Margin="-6,0,-6,0">
        <TextBlock Margin="2,1,1,1" Text="{Binding Path=stand_name}"></TextBlock>
    </Border>
</DataTemplate>
<DataTemplate x:Key="Column3_HideStandColumn">
    <Border BorderThickness="0,0,0,0" BorderBrush="Gray" Margin="-6,0,-6,0">
        <TextBlock Margin="2,1,1,1" Text="{Binding Path=stand_name}"></TextBlock>
    </Border>
</DataTemplate>

if (selectedStand.stand_name != "Все")
{
  ...
  DataTemplate dt = lstvTCKeyValue.FindResource("Column3_HideStandColumn") as DataTemplate;
  gv.Columns[2].CellTemplate = dt;
  ...
}
else
{
  ...
  DataTemplate dt = lstvTCKeyValue.FindResource("Column3_ShowStandColumn") as DataTemplate;
  gv.Columns[2].CellTemplate = dt;
  ...
}

<ControlTemplate x:Key="OnTemplate">
 <Grid ToolTip="{Binding Tag, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type CheckBox}}}">
  <Rectangle HorizontalAlignment="Left" Margin="0" VerticalAlignment="Center" Width="80" Height="20" RadiusX="3" RadiusY="3">
   <Rectangle.Fill>
    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
     <GradientStop Color="#FF6183DC" Offset="0"/>
     <GradientStop Color="#FFC6CDE0" Offset="1"/>
    </LinearGradientBrush>
   </Rectangle.Fill>
  </Rectangle>
  <TextBlock HorizontalAlignment="Left" VerticalAlignment="Center" Text="ON" TextWrapping="Wrap" Margin="8,0,0,0" FontSize="16" FontWeight="Bold" Foreground="#FFFEFCFC"/>
  <Rectangle RadiusX="3" RadiusY="3" HorizontalAlignment="Left" Margin="40,0,0,0" VerticalAlignment="Center" Width="40" Height="20">
   <Rectangle.Fill>
    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
     <GradientStop Color="#FFB5B1B1" Offset="0.004"/>
     <GradientStop Color="White" Offset="1"/>
    </LinearGradientBrush>
   </Rectangle.Fill>
  </Rectangle>
 </Grid>
</ControlTemplate>
<ControlTemplate x:Key="OffTemplate">
 <Grid ToolTip="{Binding Tag, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type CheckBox}}}">
  <Rectangle HorizontalAlignment="Left" Margin="0" VerticalAlignment="Center" Width="80" Height="20" RadiusX="3" RadiusY="3">
   <Rectangle.Fill>
    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
     <GradientStop Color="#FFE0E7F8" Offset="0"/>
     <GradientStop Color="#FFF2F4FA" Offset="1"/>
    </LinearGradientBrush>
   </Rectangle.Fill>
  </Rectangle>
  <TextBlock HorizontalAlignment="Left" VerticalAlignment="Center" Text="OFF" TextWrapping="Wrap" Margin="44,0,0,0" FontSize="16" FontWeight="Bold" Foreground="#FFB3ABAB"/>
  <Rectangle RadiusX="3" RadiusY="3" HorizontalAlignment="Left" Margin="1,0,0,0" VerticalAlignment="Center" Width="40" Height="20">
   <Rectangle.Fill>
    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
     <GradientStop Color="#FFB5B1B1" Offset="0.004"/>
     <GradientStop Color="White" Offset="1"/>
    </LinearGradientBrush>
   </Rectangle.Fill>
  </Rectangle>
 </Grid>
</ControlTemplate>

<DataTemplate x:Key="toggleTemplate">
 <Control x:Name="toggleControl" Template="{StaticResource OnTemplate}" />
 <DataTemplate.Triggers>
  <DataTrigger Binding="{Binding IsChecked, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type CheckBox}}}" Value="False">
   <Setter Property="Template" TargetName="toggleControl" Value="{StaticResource OffTemplate}" />
  </DataTrigger>
 </DataTemplate.Triggers>
</DataTemplate>

<Style TargetType="ToggleButton">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="ToggleButton">
                <Image MouseDown="Image_MouseDown" Source="{StaticResource CheckedImage}" Height="16" />
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=IsChecked, RelativeSource={RelativeSource Mode=TemplatedParent}}" Value="True">
            <Setter Property="Opacity" Value="1" />
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=IsMoueseOver, RelativeSource={RelativeSource Mode=TemplatedParent}}" Value="True">
            <Setter Property="Opacity" Value="0.7" />
        </DataTrigger>
    </Style.Triggers>
</Style>

private void Image_MouseDown(object sender, MouseButtonEventArgs e)
{
    var img = (Image)sender;
    var toggle = (ToggleButton)img.TemplatedParent;
    toggle.IsChecked = true;
}

<ControlTemplate.Triggers>
    <Trigger Property="IsChecked" Value="True">
        <Setter Property="Opacity" Value="1" />
    </Trigger>
</ControlTemplate.Triggers>