WPF MVVM: comment lier GridViewColumn à ViewModel-Collection?

J'ai pris Thomas Levesque est une excellente solution et l'a modifié pour supprimer la statique de la collection de GridViews et ajouter également la possibilité de définir la largeur d'une colonne et de format de chaîne de caractères, donc j'ai pensé partager mon code.

Modifié propriété attachée classe:

public static class GridViewColumnCollection
{
public static readonly DependencyProperty ColumnCollectionBehaviourProperty =
DependencyProperty.RegisterAttached("ColumnCollectionBehaviour", typeof(GridViewColumnCollectionBehaviour), typeof(GridViewColumnCollection), new UIPropertyMetadata(null));
public static readonly DependencyProperty ColumnsSourceProperty =
DependencyProperty.RegisterAttached("ColumnsSource", typeof(object), typeof(GridViewColumnCollection), new UIPropertyMetadata(null, GridViewColumnCollection.ColumnsSourceChanged));
public static readonly DependencyProperty DisplayMemberFormatMemberProperty =
DependencyProperty.RegisterAttached("DisplayMemberFormatMember", typeof(string), typeof(GridViewColumnCollection), new UIPropertyMetadata(null, GridViewColumnCollection.DisplayMemberFormatMemberChanged));
public static readonly DependencyProperty DisplayMemberMemberProperty =
DependencyProperty.RegisterAttached("DisplayMemberMember", typeof(string), typeof(GridViewColumnCollection), new UIPropertyMetadata(null, GridViewColumnCollection.DisplayMemberMemberChanged));
public static readonly DependencyProperty HeaderTextMemberProperty =
DependencyProperty.RegisterAttached("HeaderTextMember", typeof(string), typeof(GridViewColumnCollection), new UIPropertyMetadata(null, GridViewColumnCollection.HeaderTextMemberChanged));
public static readonly DependencyProperty WidthMemberProperty =
DependencyProperty.RegisterAttached("WidthMember", typeof(string), typeof(GridViewColumnCollection), new UIPropertyMetadata(null, GridViewColumnCollection.WidthMemberChanged));
[AttachedPropertyBrowsableForType(typeof(GridView))]
public static GridViewColumnCollectionBehaviour GetColumnCollectionBehaviour(DependencyObject obj)
{
return (GridViewColumnCollectionBehaviour)obj.GetValue(ColumnCollectionBehaviourProperty);
}
public static void SetColumnCollectionBehaviour(DependencyObject obj, GridViewColumnCollectionBehaviour value)
{
obj.SetValue(ColumnCollectionBehaviourProperty, value);
}
[AttachedPropertyBrowsableForType(typeof(GridView))]
public static object GetColumnsSource(DependencyObject obj)
{
return (object)obj.GetValue(ColumnsSourceProperty);
}
public static void SetColumnsSource(DependencyObject obj, object value)
{
obj.SetValue(ColumnsSourceProperty, value);
}
[AttachedPropertyBrowsableForType(typeof(GridView))]
public static string GetDisplayMemberFormatMember(DependencyObject obj)
{
return (string)obj.GetValue(DisplayMemberFormatMemberProperty);
}
public static void SetDisplayMemberFormatMember(DependencyObject obj, string value)
{
obj.SetValue(DisplayMemberFormatMemberProperty, value);
}
[AttachedPropertyBrowsableForType(typeof(GridView))]
public static string GetDisplayMemberMember(DependencyObject obj)
{
return (string)obj.GetValue(DisplayMemberMemberProperty);
}
public static void SetDisplayMemberMember(DependencyObject obj, string value)
{
obj.SetValue(DisplayMemberMemberProperty, value);
}
[AttachedPropertyBrowsableForType(typeof(GridView))]
public static string GetHeaderTextMember(DependencyObject obj)
{
return (string)obj.GetValue(HeaderTextMemberProperty);
}
public static void SetHeaderTextMember(DependencyObject obj, string value)
{
obj.SetValue(HeaderTextMemberProperty, value);
}
[AttachedPropertyBrowsableForType(typeof(GridView))]
public static string GetWidthMember(DependencyObject obj)
{
return (string)obj.GetValue(WidthMemberProperty);
}
public static void SetWidthMember(DependencyObject obj, string value)
{
obj.SetValue(WidthMemberProperty, value);
}
private static void ColumnsSourceChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
GridViewColumnCollection.GetOrCreateColumnCollectionBehaviour(sender).ColumnsSource = e.NewValue;
}
private static void DisplayMemberFormatMemberChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
GridViewColumnCollection.GetOrCreateColumnCollectionBehaviour(sender).DisplayMemberFormatMember = e.NewValue as string;
}
private static void DisplayMemberMemberChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
GridViewColumnCollection.GetOrCreateColumnCollectionBehaviour(sender).DisplayMemberMember = e.NewValue as string;
}
private static void HeaderTextMemberChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
GridViewColumnCollection.GetOrCreateColumnCollectionBehaviour(sender).HeaderTextMember = e.NewValue as string;
}
private static void WidthMemberChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
GridViewColumnCollection.GetOrCreateColumnCollectionBehaviour(sender).WidthMember = e.NewValue as string;
}
private static GridViewColumnCollectionBehaviour GetOrCreateColumnCollectionBehaviour(DependencyObject source)
{
GridViewColumnCollectionBehaviour behaviour = GetColumnCollectionBehaviour(source);
if (behaviour == null)
{
GridView typedSource = source as GridView;
if (typedSource == null)
{
throw new Exception("This property can only be set on controls deriving GridView");
}
behaviour = new GridViewColumnCollectionBehaviour(typedSource);
SetColumnCollectionBehaviour(typedSource, behaviour);
}
return behaviour;
}
}

Comportement (ce qui est stocké à l'encontre de chaque GridView et élimine la nécessité de stocker la collection-GridView mappages de manière centralisée):

public class GridViewColumnCollectionBehaviour
{
private object columnsSource;
private GridView gridView;
public GridViewColumnCollectionBehaviour(GridView gridView)
{
this.gridView = gridView;
}
public object ColumnsSource
{
get { return this.columnsSource; }
set
{
object oldValue = this.columnsSource;
this.columnsSource = value;
this.ColumnsSourceChanged(oldValue, this.columnsSource);
}
}
public string DisplayMemberFormatMember { get; set; }
public string DisplayMemberMember { get; set; }
public string HeaderTextMember { get; set; }
public string WidthMember { get; set; }
private void AddHandlers(ICollectionView collectionView)
{
collectionView.CollectionChanged += this.ColumnsSource_CollectionChanged;
}
private void ColumnsSource_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
ICollectionView view = sender as ICollectionView;
if (this.gridView == null)
{
return;
}
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
for (int i = 0; i < e.NewItems.Count; i++)
{
GridViewColumn column = CreateColumn(e.NewItems[i]);
gridView.Columns.Insert(e.NewStartingIndex + i, column);
}
break;
case NotifyCollectionChangedAction.Move:
List<GridViewColumn> columns = new List<GridViewColumn>();
for (int i = 0; i < e.OldItems.Count; i++)
{
GridViewColumn column = gridView.Columns[e.OldStartingIndex + i];
columns.Add(column);
}
for (int i = 0; i < e.NewItems.Count; i++)
{
GridViewColumn column = columns[i];
gridView.Columns.Insert(e.NewStartingIndex + i, column);
}
break;
case NotifyCollectionChangedAction.Remove:
for (int i = 0; i < e.OldItems.Count; i++)
{
gridView.Columns.RemoveAt(e.OldStartingIndex);
}
break;
case NotifyCollectionChangedAction.Replace:
for (int i = 0; i < e.NewItems.Count; i++)
{
GridViewColumn column = CreateColumn(e.NewItems[i]);
gridView.Columns[e.NewStartingIndex + i] = column;
}
break;
case NotifyCollectionChangedAction.Reset:
gridView.Columns.Clear();
CreateColumns(sender as ICollectionView);
break;
default:
break;
}
}
private void ColumnsSourceChanged(object oldValue, object newValue)
{
if (this.gridView != null)
{
gridView.Columns.Clear();
if (oldValue != null)
{
ICollectionView view = CollectionViewSource.GetDefaultView(oldValue);
if (view != null)
{
this.RemoveHandlers(view);
}
}
if (newValue != null)
{
ICollectionView view = CollectionViewSource.GetDefaultView(newValue);
if (view != null)
{
this.AddHandlers(view);
this.CreateColumns(view);
}
}
}
}
private GridViewColumn CreateColumn(object columnSource)
{
GridViewColumn column = new GridViewColumn();
if (!string.IsNullOrEmpty(this.HeaderTextMember))
{
column.Header = GetPropertyValue(columnSource, this.HeaderTextMember);
}
if (!string.IsNullOrEmpty(this.DisplayMemberMember))
{
string propertyName = GetPropertyValue(columnSource, this.DisplayMemberMember) as string;
string format = null;
if (!string.IsNullOrEmpty(this.DisplayMemberFormatMember))
{
format = GetPropertyValue(columnSource, this.DisplayMemberFormatMember) as string;
}
if (string.IsNullOrEmpty(format))
{
format = "{0}";
}
column.DisplayMemberBinding = new Binding(propertyName) { StringFormat = format };
}
if (!string.IsNullOrEmpty(this.WidthMember))
{
double width = (double)GetPropertyValue(columnSource, this.WidthMember);
column.Width = width;
}
return column;
}
private void CreateColumns(ICollectionView collectionView)
{
foreach (object item in collectionView)
{
GridViewColumn column = this.CreateColumn(item);
this.gridView.Columns.Add(column);
}
}
private object GetPropertyValue(object obj, string propertyName)
{
object returnVal = null;
if (obj != null)
{
PropertyInfo prop = obj.GetType().GetProperty(propertyName);
if (prop != null)
{
returnVal = prop.GetValue(obj, null);
}
}
return returnVal;
}
private void RemoveHandlers(ICollectionView collectionView)
{
collectionView.CollectionChanged -= this.ColumnsSource_CollectionChanged;
}
}