Add project files.

MainWindow.xaml

@@ -0,0 +1,97 @@
+<Window x:Name="Processing" x:Class="ProgressBar.MainWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        mc:Ignorable="d"
+        Title="Processing..."
+        HorizontalAlignment="Center"
+        VerticalAlignment="Center"
+        Width="360"
+        Height="100"
+        ResizeMode="NoResize"
+        WindowStartupLocation="CenterScreen" Topmost="True">
+    <Viewbox HorizontalAlignment="Center" VerticalAlignment="Center">
+        <Grid VerticalAlignment="Center" HorizontalAlignment="Center">
+            <Grid.RowDefinitions>
+                <RowDefinition Height="60" Name="RowActions"/>
+            </Grid.RowDefinitions>
+            <Grid.ColumnDefinitions>
+                <ColumnDefinition Width="Auto"/>
+                <ColumnDefinition Width="150"/>
+            </Grid.ColumnDefinitions>
+
+            <Button
+                x:Name="BtnStart"
+                Content="Start processing"
+                Grid.Column="1"
+                Margin="6,20,4,20"
+                Click="BtnStart_Click"
+                VerticalAlignment="Center"
+                />
+
+            <Grid Margin="5,5,0,0">
+                <Grid.RowDefinitions>
+                    <RowDefinition Height="20" />
+                </Grid.RowDefinitions>
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="30"/>
+                    <ColumnDefinition Width="Auto"/>
+                </Grid.ColumnDefinitions>
+
+                <TextBox
+                    x:Name="Amount"
+                    Grid.Column="0"
+                    Text="{Binding Countdown, FallbackValue=1, Mode=TwoWay, NotifyOnTargetUpdated=True, NotifyOnSourceUpdated=True, NotifyOnValidationError=True, StringFormat=\{0:D\}, TargetNullValue=1, UpdateSourceTrigger=LostFocus}"
+                    MaxLength="3"
+                    TextAlignment="Right"
+                    BorderBrush="{x:Null}"
+                    Background="{x:Null}"
+                    SelectionBrush="{x:Null}"
+                    IsEnabled="False"
+                />
+                <Label
+                    x:Name="AmountLabel"
+                    Grid.Column="1"
+                    Content="seconds to process" Padding="5,0"
+                />
+            </Grid>
+            <Slider
+                x:Name="Slider"
+                VerticalAlignment="Bottom"
+                Value="{Binding Countdown, FallbackValue=1, Mode=TwoWay, NotifyOnTargetUpdated=True, NotifyOnSourceUpdated=True, NotifyOnValidationError=True, TargetNullValue=1, ValidatesOnDataErrors=True, ValidatesOnExceptions=True}"
+                Margin="10,0,0,10"
+                ValueChanged="Slider_ValueChanged"
+                Minimum="1"
+                Maximum="3600"
+                SmallChange="1"
+                />
+
+            <ProgressBar
+                x:Name="ProgressBar"
+                Grid.Column="0"
+                Grid.ColumnSpan="2"
+                Grid.Row="0"
+                Value="0"
+                Maximum="100"
+                Height="20"
+                Margin="10,5"
+                Visibility="Hidden"
+                />
+
+            <Button
+                x:Name="ButtonDone"
+                Grid.ColumnSpan="2"
+                Grid.RowSpan="2"
+                AutomationProperties.Name="ButtonDone"
+                Content="Done processing. Click to confirm and close."
+                Click="ButtonDone_Click"
+                Visibility="Hidden"
+                VerticalAlignment="Center"
+                HorizontalAlignment="Center"
+                Padding="5"
+                />
+
+        </Grid>
+    </Viewbox>
+</Window>