Tag

PivotGridField.ValueTemplate Property

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

Namespace: DevExpress.Xpf.PivotGrid

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

Declaration

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

Property Value

Type Description
DataTemplate

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

Remarks

If the ValueTemplate is not specified, the field values are displayed via the PivotGridControl.FieldValueTemplate template. The PivotGridField.ActualValueTemplate property allows you to obtain which template is currently used.

You can implement custom logic to choose the required template using the PivotGridField.ValueTemplateSelector property.

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