Create a Resizable Panel at Runtime

I'm trying to make a grid to be resizable by the user at runtime. I found a quite a few examples, but they all seem to make it a overly-complicated by using adorners etc.

I'd like just to use one simple control in the bottom-right corner, such as a thumb or ResizeGrip, that will enable to user to resize the panel.

You can use a Thumb to calculate the Resize logic and override the Style of a ContentPresenter then you can add a Grid to the ContentPresenter

Working Example:

Code:

namespace WpfApplication12
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }

    public class ResizeThumb : Thumb
    {
        public ResizeThumb()
        {
            DragDelta += new DragDeltaEventHandler(this.ResizeThumb_DragDelta);
        }

        private void ResizeThumb_DragDelta(object sender, DragDeltaEventArgs e)
        {
            Control designerItem = this.DataContext as Control;

            if (designerItem != null)
            {
                double deltaVertical, deltaHorizontal;

                switch (VerticalAlignment)
                {
                    case VerticalAlignment.Bottom:
                        deltaVertical = Math.Min(-e.VerticalChange, designerItem.ActualHeight - designerItem.MinHeight);
                        designerItem.Height -= deltaVertical;
                        break;
                    case VerticalAlignment.Top:
                        deltaVertical = Math.Min(e.VerticalChange, designerItem.ActualHeight - designerItem.MinHeight);
                        Canvas.SetTop(designerItem, Canvas.GetTop(designerItem) + deltaVertical);
                        designerItem.Height -= deltaVertical;
                        break;
                    default:
                        break;
                }

                switch (HorizontalAlignment)
                {
                    case HorizontalAlignment.Left:
                        deltaHorizontal = Math.Min(e.HorizontalChange, designerItem.ActualWidth - designerItem.MinWidth);
                        Canvas.SetLeft(designerItem, Canvas.GetLeft(designerItem) + deltaHorizontal);
                        designerItem.Width -= deltaHorizontal;
                        break;
                    case HorizontalAlignment.Right:
                        deltaHorizontal = Math.Min(-e.HorizontalChange, designerItem.ActualWidth - designerItem.MinWidth);
                        designerItem.Width -= deltaHorizontal;
                        break;
                    default:
                        break;
                }
            }

            e.Handled = true;
        }
    }

}

Xaml:

<Window x:Class="WpfApplication12.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication12"
        Title="MainWindow" Height="350" Width="525">

    <Window.Resources>

        <Style TargetType="{x:Type ContentControl}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ContentControl}">
                        <Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
                            <Control x:Name="resizer">
                                <Control.Style>
                                    <Style TargetType="{x:Type Control}">
                                        <Setter Property="Template">
                                            <Setter.Value>
                                                <ControlTemplate TargetType="{x:Type Control}">
                                                    <Grid Margin="-3">
                                                        <local:ResizeThumb Width="7" Height="7" Margin="-2" Cursor="SizeNWSE" VerticalAlignment="Bottom" HorizontalAlignment="Right"/>
                                                    </Grid>
                                                </ControlTemplate>
                                            </Setter.Value>
                                        </Setter>
                                    </Style>
                                </Control.Style>
                            </Control>
                            <ContentPresenter Content="{TemplateBinding Content}"/>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

    </Window.Resources>

    <Canvas>
        <ContentControl Width="200" Height="100"  Canvas.Left="10" Canvas.Top="10" >
            <Grid Background="Blue">
                <TextBlock Text="ResizeGrid" HorizontalAlignment="Center" VerticalAlignment="Center" Foreground="Red" />
            </Grid>
        </ContentControl>
    </Canvas>

</Window>

Result: