PivotGridControl.FieldValueTemplate Property

Gets or sets a template used to display field values. This is a dependency property.

Namespace: DevExpress.Xpf.PivotGrid

Assembly: DevExpress.Xpf.PivotGrid.v20.1.dll

Declaration

public DataTemplate FieldValueTemplate { get; set; }
Public Property FieldValueTemplate As DataTemplate

Property Value

Type Description
DataTemplate

A DataTemplate object representing the template used to display field values.

Remarks

The FieldValueTemplate is applied to those fields whose PivotGridField.ValueTemplate property is set to null. The PivotGridField.ActualValueTemplate property allows you to obtain which template is currently used for a particular field.

You can implement custom logic to choose the required template using the PivotGridControl.FieldValueTemplateSelector property (or the PivotGridField.ValueTemplateSelector property to do this for individual fields).

Examples

This example demonstrates how to define a custom template used to display field values. The template in this example displays field values with images, as shown in the picture below.

Create the Field Value Template

TIP

A complete sample project is available in the DevExpress Code Examples database at http://www.devexpress.com/example=E2191.

A custom control CategoriesControl displays the field's text along with the related image. The required information is retrieved from the DataContext which is converted to the FieldValueElementData type.

A template for a certain field is assigned to the PivotGridField.ValueTemplate property . Also, you can use PivotGridControl.FieldValueTemplate property to apply a custom template to all field values.

using DevExpress.Xpf.PivotGrid;
using HowToCreateFieldValueTemplate.CategoryPicturesTableAdapters;
using System;
using System.Collections.Generic;
using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace HowToCreateFieldValueTemplate
{
    public class CategoriesControl : Control, IWeakEventListener {

        #region static staff
        static CategoriesTableAdapter categoriesTableAdapter;
        static Dictionary<string, ImageSource> categoriesPictures;
        public static readonly DependencyProperty ImageSourceProperty;

        static CategoriesControl() {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(CategoriesControl), 
                new FrameworkPropertyMetadata(typeof(CategoriesControl)));
            Type ownerType = typeof(CategoriesControl);
            ImageSourceProperty = DependencyProperty.Register("ImageSource", typeof(ImageSource),
                   ownerType, new UIPropertyMetadata());
            categoriesPictures = new Dictionary<string, ImageSource>();
        }

        static CategoriesTableAdapter CategoriesTableAdapter {
            get {
                if(categoriesTableAdapter == null)
                    categoriesTableAdapter = new CategoriesTableAdapter();
                return categoriesTableAdapter;
            }
        }

        static ImageSource GetImage(string categoryName) {
            if(string.IsNullOrEmpty(categoryName)) return null;
            if(categoriesPictures.ContainsKey(categoryName)) {
                return categoriesPictures[categoryName];
            } else {
                byte[] icon = CategoriesTableAdapter.GetIconImageByName(categoryName) as byte[];
                if(icon == null || icon.Length == 0) {
                    return null;
                }
                BitmapDecoder img = new PngBitmapDecoder(new MemoryStream(icon), 
                    BitmapCreateOptions.None, 
                    BitmapCacheOption.OnLoad);
                ImageSource imageSource = img.Frames[0];
                if(imageSource.Height < 1) return null;
                categoriesPictures.Add(categoryName, imageSource);
                return imageSource;
            }
        }

        #endregion

        public CategoriesControl()
            : base() {
            FrameworkElementDataContextChangedEventManager.AddListener(this, this);
            Unloaded += OnUnloaded;
        }

        public ImageSource ImageSource {
            get { return (ImageSource)GetValue(ImageSourceProperty); }
            set { SetValue(ImageSourceProperty, value); }
        }

        void OnUnloaded(object sender, RoutedEventArgs e) {
            ImageSource = null;
        }
        void OnDataContextChanged() {
            SetImageSource();
        }
        void SetImageSource() {
            FieldValueElementData item = this.DataContext as FieldValueElementData;
            if(item != null && !item.IsOthersRow && !string.IsNullOrEmpty(item.DisplayText)) {
                ImageSource = CategoriesControl.GetImage(item.Value as string);
            } else {
                ImageSource = null;
            }
        }

        #region IWeakEventListener Members
        bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e) {
            return OnReceiveWeakEvent(managerType, e);
        }
        protected virtual bool OnReceiveWeakEvent(Type managerType, EventArgs e) {
            if(managerType == typeof(FrameworkElementDataContextChangedEventManager)) {
                OnDataContextChanged();
                return true;
            }
            return false;
        }
        #endregion

        #region FrameworkElementDataContextChangedEventManager

        public class FrameworkElementDataContextChangedEventManager : WeakEventManager {
            static FrameworkElementDataContextChangedEventManager CurrentManager {
                get {
                    Type managerType = typeof(FrameworkElementDataContextChangedEventManager);
                    FrameworkElementDataContextChangedEventManager currentManager =
                        (FrameworkElementDataContextChangedEventManager)WeakEventManager
                        .GetCurrentManager(managerType);
                    if(currentManager == null) {
                        currentManager = new FrameworkElementDataContextChangedEventManager();
                        WeakEventManager.SetCurrentManager(managerType, currentManager);
                    }
                    return currentManager;
                }
            }

            FrameworkElementDataContextChangedEventManager() { }

            public static void AddListener(FrameworkElement source, IWeakEventListener listener) {
                CurrentManager.ProtectedAddListener(source, listener);
            }
            public static void RemoveListener(FrameworkElement source, IWeakEventListener listener) {
                CurrentManager.ProtectedRemoveListener(source, listener);
            }
            protected override void StartListening(object source) {
                FrameworkElement FrameworkElement = (FrameworkElement)source;
                FrameworkElement.DataContextChanged += OnDataContextChanged;
            }
            protected override void StopListening(object source) {
                FrameworkElement FrameworkElement = (FrameworkElement)source;
                FrameworkElement.DataContextChanged -= OnDataContextChanged;
            }
            void OnDataContextChanged(object sender, DependencyPropertyChangedEventArgs e) {
                base.DeliverEvent(sender, null);
            }
        }
        #endregion
    }
}
See Also