If you want to implement a grid for your Windows Phone 7 app you have to use a Listbox control because of the missing DataGrid at the Windows Phone 7 platform. A first idea for contsructing a Grid then could be to use the WrapPanel control in your ItemTemplate of the Listbox control. But if you do this, the data virtualization of the ListBox will be disabled (Virtualizing Data in Windows Phone 7 Silverlight Applications - Peter Torr's Blog - Site Home - MSDN Blogs). This will increase the loading time of your ListBox and results in a very poor UX handling. The problem is, that you can not use any complex data structures in the ItemTemplate at a Listbox for Windows Phone 7. Every line in the Listbox should be one data line. So a solution for developing a grid styled Listbox is to implement a RowAdapter class for your bounded data.
Here a implementation of a RowAdapter, I used in one of my projects:
public class RowAdapter<TItemType> : IList<IEnumerable<TItemType>>, INotifyCollectionChanged
{
private readonly IList<TItemType> _sourceList;
private readonly int _columns;
private class RowObject : IEnumerable<TItemType>
{
internal readonly RowAdapter<TItemType> Parent;
internal readonly int StartIndex;
public RowObject(RowAdapter<TItemType> parent, int startIndex)
{
Parent = parent;
StartIndex = startIndex;
}
#region IEnumerable<TItemType> Members
public IEnumerator<TItemType> GetEnumerator()
{
int limit = Parent._sourceList.Count;
int end = Math.Min(StartIndex + Parent._columns, limit);
for (int pos = StartIndex; pos < end; ++pos)
{
yield return Parent._sourceList[pos];
}
}
#endregion
#region IEnumerable Members
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
#endregion
}
public RowAdapter(IList<TItemType> sourceList, int columns)
{
if (null == sourceList)
throw new ArgumentNullException("sourceList", Resource.RowAdapter_RowAdapter_sourceList_is_null);
if (columns <= 0)
throw new ArgumentOutOfRangeException("columns", Resource.RowAdapter_RowAdapter_ColumnsGreaterOne);
// We require the source list to implement IList because we
// need to know how many item there are
_sourceList = sourceList;
_columns = columns;
var sourceNotify = sourceList as INotifyCollectionChanged;
if (null != sourceNotify)
{
sourceNotify.CollectionChanged += OnSourceCollectionChanged;
}
}
#region IList<IEnumerable<TItemType>> Members
public int IndexOf(IEnumerable<TItemType> item)
{
var realItem = item as RowObject;
if (null == realItem || !ReferenceEquals(realItem.Parent, this))
return -1; // It does not belong to this collection
Debug.Assert(0 == realItem.StartIndex % _columns, "RowObject item has a wierd index");
return realItem.StartIndex / _columns;
}
public void Insert(int index, IEnumerable<TItemType> item)
{
throw new NotSupportedException();
}
public IEnumerable<TItemType> this[int index]
{
get
{
if (index < 0 || index > Count)
return null;
return InternalGetRow(index);
}
set
{
throw new NotSupportedException();
}
}
public void RemoveAt(int index)
{
throw new NotSupportedException();
}
#endregion
#region ICollection<IEnumerable<TItemType>> Members
public void Add(IEnumerable<TItemType> item)
{
throw new NotSupportedException();
}
public bool Contains(IEnumerable<TItemType> item)
{
var realItem = item as RowObject;
return null != realItem && object.ReferenceEquals(realItem.Parent, this);
}
public void CopyTo(IEnumerable<TItemType>[] array, int arrayIndex)
{
// I haven't implemented this. It is easy to implement if you need it
throw new NotImplementedException();
}
public bool Remove(IEnumerable<TItemType> item)
{
throw new NotSupportedException();
}
public void Clear()
{
throw new NotSupportedException();
}
public int Count
{
get
{
return (_sourceList.Count + (_columns - 1)) / _columns;
}
}
public bool IsReadOnly
{
get { return true; }
}
#endregion
#region IEnumerable<IEnumerable<TItemType>> Members
public IEnumerator<IEnumerable<TItemType>> GetEnumerator()
{
for (int i = 0; i < Count; ++i)
{
yield return InternalGetRow(i);
}
}
#endregion
#region IEnumerable Members
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
#endregion
#region INotifyCollectionChanged Members
public event NotifyCollectionChangedEventHandler CollectionChanged;
private void FireCollectionChanged()
{
var handler = CollectionChanged;
if (null != handler)
{
handler(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
}
private void OnSourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
FireCollectionChanged();
}
#endregion
private RowObject InternalGetRow(int index)
{
return new RowObject(this, index * _columns);
}
}
