Click here to Skip to main content
Click here to Skip to main content
Add your own
alternative version
Go to top

Auto-filter for Microsoft WPF DataGrid

, 29 Jan 2009
Allows auto filtering functionality for DataGrid columns.
WPFGridFilter.zip
WPFGridFilter
PowerCollections
PowerCollections.csproj.user
Properties
Stepi.Collections
bin
Filters
Properties
Stepi.UIFilters
bin
Initializers
Properties
Settings.settings
Themes
Test.GridSorting
bin
Debug
Test.GridFilter.vshost.exe
Properties
Settings.settings
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Collections;
using Stepi.Collections.Filters;
using System.ComponentModel;
using Stepi.Collections;
using System.Reflection;

namespace Stepi.UIFilters
{
    public class MultiValuePresentationModel<T> : IMultiValuePresentationModel
    {
        private static readonly PropertyChangedEventArgs _activeEventArgs = new PropertyChangedEventArgs("IsActive");

        private bool _isActive;
        private readonly string _name;
        private readonly ObservableCollection<UIFilterValueItem<T>> _availableValues = new ObservableCollection<UIFilterValueItem<T>>();
        private readonly IMultiValueFilter<T> _filter;
        private readonly ICollectionView _collection;
        public event PropertyChangedEventHandler PropertyChanged = delegate { };

        public MultiValuePresentationModel(IMultiValueFilter<T> filter, string name, ICollectionView collection)
        {
            if (filter == null)
            {
                throw new ArgumentNullException("filter");
            }
            if (collection == null)
            {
                throw new ArgumentNullException("filteredCollection");
            }
            _filter = filter;
            _collection = collection;
            _name = name;
            _availableValues.CollectionChanged += new NotifyCollectionChangedEventHandler(OnAvailableValuesCollectionChanged);
        }

        /// <summary>
        /// Gets the name(description) of the filter
        /// </summary>
        /// <value>The name.</value>
        public string Name
        {
            get { return _name; }
        }

        /// <summary>
        /// Gets or sets a value indicating whether this filter is active.
        /// </summary>
        /// <value><c>true</c> if this filter is active; otherwise, <c>false</c>.</value>
        public bool IsActive
        {
            get { return _isActive; }
            set
            {
                if (_isActive != value)
                {
                    _isActive = value;
                    PropertyChanged(this, _activeEventArgs);
                }
            }
        }

        /// <summary>
        /// Gets or sets a value indicating the filter can be applied
        /// </summary>
        /// <value><c>true</c> if this instance can apply; otherwise, <c>false</c>.</value>
        public bool CanApply
        {
            get { return true; }
            set { }
        }

        /// <summary>
        /// Gets the available values.
        /// </summary>
        /// <value>The available values.</value>
        public IList<UIFilterValueItem<T>> AvailableValues
        {
            get { return _availableValues; }
        }

        /// <summary>
        /// Gets the available values.
        /// </summary>
        /// <value>The available values.</value>
        IEnumerable IMultiValuePresentationModel.AvailableValues
        {
            get { return _availableValues; }
        }

        public  IFilter Filter
        {
            get { return _filter; }
        }

        /// <summary>
        /// Gives the UI the option to update its data.
        /// </summary>
        /// <param name="isDisplaying">if set to <c>true</c> [is displaying].</param>
        public void UpdateData(bool isDisplaying)
        {
            if (isDisplaying)
            {
                _availableValues.Clear();
                UpdateAvailableValues();
            }
        }

        /// <summary>
        /// Updates the available values.
        /// </summary>
        private void UpdateAvailableValues()
        {
            PropertyInfo propInfo = Filter.PropertyInfo;
            Dictionary<T, bool> localValues = new Dictionary<T, bool>();
            foreach (object element in _collection.SourceCollection)
            {
                try
                {
                    T value = (T)propInfo.GetValue(element, null);
                    if (!localValues.ContainsKey(value))
                    {
                        localValues[value] = true;
                        UIFilterValueItem<T> item = new UIFilterValueItem<T>(value);
                        if (_filter.Values.Contains(value))
                        {
                            item.IsSelected = true;
                        }
                        _availableValues.Add(item);
                    }
                }
                catch
                { }
            }
        }

        /// <summary>
        /// Called when [available values collection changed].
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="System.Collections.Specialized.NotifyCollectionChangedEventArgs"/> instance containing the event data.</param>
        private void OnAvailableValuesCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            if (e.NewItems != null)
            {
                foreach (UIFilterValueItem<T> value in e.NewItems)
                {
                    //AddValue(value);
                    value.PropertyChanged+=new PropertyChangedEventHandler(OnUIElementIsSelectedPropertyChanged);
                    if (value.IsSelected == true)
                    {
                        AddValue(value);
                    }
                }
            }
            if (e.OldItems != null)
            {
                foreach (UIFilterValueItem<T> value in e.OldItems)
                {
                    //value.SelectedChanged -= new EventHandler(OnFilterValueSelectedChanged);
                    value.PropertyChanged -= new PropertyChangedEventHandler(OnUIElementIsSelectedPropertyChanged);
                    RemoveValue(value);
                }
            }
        }

        /// <summary>
        /// Called when [UI element is selected property changed].
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="System.ComponentModel.PropertyChangedEventArgs"/> instance containing the event data.</param>
        private void OnUIElementIsSelectedPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            UIFilterValueItem<T> value = (UIFilterValueItem<T>)sender;
            if (value.IsSelected == true)
            {
                AddValue(value);
            }
            else 
            {
                RemoveValue(value);
            }
        }

        /// <summary>
        /// Removes the value.
        /// </summary>
        /// <param name="value">The value.</param>
        private void RemoveValue(UIFilterValueItem<T> value)
        {
            if (value.IsSelected == false)
            {
                _filter.Values.Remove(value.Value);
            }
        }

        /// <summary>
        /// Adds the value.
        /// </summary>
        /// <param name="value">The value.</param>
        private void AddValue(UIFilterValueItem<T> value)
        {
            if (value.IsSelected == true && !_filter.Values.Contains(value.Value))
            {
                _filter.Values.Add(value.Value);
            }
        }

        /// <summary>
        /// Called when [filter value selected changed].
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
        private void OnFilterValueSelectedChanged(object sender, EventArgs e)
        {
            UIFilterValueItem<T> value = (UIFilterValueItem<T>)sender;
            AddValue(value);
        }
    }
}

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article, along with any associated source code and files, is licensed under The Eclipse Public License 1.0

Share

About the Author

Stefan Bocutiu
Software Developer (Senior) Lab49
United Kingdom United Kingdom
No Biography provided

| Advertise | Privacy | Mobile
Web04 | 2.8.140926.1 | Last Updated 29 Jan 2009
Article Copyright 2009 by Stefan Bocutiu
Everything else Copyright © CodeProject, 1999-2014
Terms of Service
Layout: fixed | fluid