Converting UserControl and Code-Behind to Style and Dependency Property

Question

How can I convert a customNumericUpDown created using a UserControl and Code-Behind to a ResourceDictionary and a C# class where all the DependencyProperties are defined? I want to copy and paste the ResourceDictionary into Themes.Generic.xaml. While I know how to do this for the Properties, what about the Methods? Here's the link to my customControl Github repository for reference: https://github.com/MeshkaM/customNUD.

Answer

Hi,@Jin Ka . Welcome to Microsoft Q&A.

Here is a complete example of a NumericUpDown custom control that uses a ResourceDictionary for styling and defines Dependency Properties. The control includes event handling for value changes. You could try to refer to it.

I removed the code Style="{StaticResource MaterialDesignFloatingHintTextBox}" here. Since I will get an error when adding this code, I haven't determined the reason yet.

NumericUpDown.cs:


using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Input;

namespace DecimalUpDownCustomizationTEST
{
   /// 
  /// Follow steps 1a or 1b and then 2 to use this custom control in a XAML file.
  ///
  /// Step 1a) Using this custom control in a XAML file that exists in the current project.
  /// Add this XmlNamespace attribute to the root element of the markup file where it is 
  /// to be used:
  ///
  ///     xmlns:MyNamespace="clr-namespace:DecimalUpDownCustomizationTEST"
  ///
  ///
  /// Step 1b) Using this custom control in a XAML file that exists in a different project.
  /// Add this XmlNamespace attribute to the root element of the markup file where it is 
  /// to be used:
  ///
  ///     xmlns:MyNamespace="clr-namespace:DecimalUpDownCustomizationTEST;assembly=DecimalUpDownCustomizationTEST"
  ///
  /// You will also need to add a project reference from the project where the XAML file lives
  /// to this project and Rebuild to avoid compilation errors:
  ///
  ///     Right click on the target project in the Solution Explorer and
  ///     "Add Reference"->"Projects"->[Browse to and select this project]
  ///
  ///
  /// Step 2)
  /// Go ahead and use your control in the XAML file.
  ///
  ///     
  ///
  /// 

  [TemplatePart(Name = "UpButtonElement", Type = typeof(RepeatButton))]
  [TemplatePart(Name = "DownButtonElement", Type = typeof(RepeatButton))]
  [TemplateVisualState(Name = "Positive", GroupName = "ValueStates")]
  [TemplateVisualState(Name = "Negative", GroupName = "ValueStates")]
  [TemplateVisualState(Name = "Focused", GroupName = "FocusedStates")]
  [TemplateVisualState(Name = "Unfocused", GroupName = "FocusedStates")]
  public class NumericUpDown : Control
  {
    public NumericUpDown()
    {
      DefaultStyleKey = typeof(NumericUpDown);
      this.IsTabStop = true;
    }

    public static readonly DependencyProperty ValueProperty =
        DependencyProperty.Register(
            "Value", typeof(double), typeof(NumericUpDown),
            new PropertyMetadata(
                new PropertyChangedCallback(ValueChangedCallback)));

    public double Value
    {
      get
      {
        return (double)GetValue(ValueProperty);
      }

      set
      {
        SetValue(ValueProperty, value);
      }
    }

    private static void ValueChangedCallback(DependencyObject obj,
        DependencyPropertyChangedEventArgs args)
    {
      NumericUpDown ctl = (NumericUpDown)obj;
      double newValue = (double)args.NewValue;

      ctl.UpdateStates(true);

      ctl.OnValueChanged(
          new ValueChangedEventArgs(NumericUpDown.ValueChangedEvent,
              newValue));
    }

    public static readonly RoutedEvent ValueChangedEvent =
        EventManager.RegisterRoutedEvent("ValueChanged", RoutingStrategy.Direct,
                      typeof(ValueChangedEventHandler), typeof(NumericUpDown));

    public event ValueChangedEventHandler ValueChanged
    {
      add { AddHandler(ValueChangedEvent, value); }
      remove { RemoveHandler(ValueChangedEvent, value); }
    }

    protected virtual void OnValueChanged(ValueChangedEventArgs e)
    {
      RaiseEvent(e);
    }

    private void UpdateStates(bool useTransitions)
    {
      if (Value >= 0)
      {
        VisualStateManager.GoToState(this, "Positive", useTransitions);
      }
      else
      {
        VisualStateManager.GoToState(this, "Negative", useTransitions);
      }

      if (IsFocused)
      {
        VisualStateManager.GoToState(this, "Focused", useTransitions);
      }
      else
      {
        VisualStateManager.GoToState(this, "Unfocused", useTransitions);
      }
    }

    public override void OnApplyTemplate()
    {
      UpButtonElement = GetTemplateChild("UpButton") as RepeatButton;
      DownButtonElement = GetTemplateChild("DownButton") as RepeatButton;
    
      UpdateStates(false);
    }

    private RepeatButton downButtonElement;

    private RepeatButton DownButtonElement
    {
      get
      {
        return downButtonElement;
      }

      set
      {
        if (downButtonElement != null)
        {
          downButtonElement.Click -=
              new RoutedEventHandler(downButtonElement_Click);
        }
        downButtonElement = value;

        if (downButtonElement != null)
        {
          downButtonElement.Click +=
              new RoutedEventHandler(downButtonElement_Click);
        }
      }
    }

    void downButtonElement_Click(object sender, RoutedEventArgs e)
    {
      Value=Value-0.1;
    }

    private RepeatButton upButtonElement;

    private RepeatButton UpButtonElement
    {
      get
      {
        return upButtonElement;
      }

      set
      {
        if (upButtonElement != null)
        {
          upButtonElement.Click -=
              new RoutedEventHandler(upButtonElement_Click);
        }
        upButtonElement = value;

        if (upButtonElement != null)
        {
          upButtonElement.Click +=
              new RoutedEventHandler(upButtonElement_Click);
        }
      }
    }

    void upButtonElement_Click(object sender, RoutedEventArgs e)
    {
      Value = Value +0.1;
    }

    protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
    {
      base.OnMouseLeftButtonDown(e);
      Focus();
    }


    protected override void OnGotFocus(RoutedEventArgs e)
    {
      base.OnGotFocus(e);
      UpdateStates(true);
    }

    protected override void OnLostFocus(RoutedEventArgs e)
    {
      base.OnLostFocus(e);
      UpdateStates(true);
    }
  }

  public delegate void ValueChangedEventHandler(object sender, ValueChangedEventArgs e);

  public class ValueChangedEventArgs : RoutedEventArgs
  {
    private double _value;

    public ValueChangedEventArgs(RoutedEvent id, double num)
    {
      _value = num;
      RoutedEvent = id;
    }

    public double Value
    {
      get { return _value; }
    }
  }

}

MainWindow.xaml:

The result:

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Converting UserControl and Code-Behind to Style and Dependency Property

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