How to maintain the group expanded states while ungrouping and grouping the columns at runtime in WPF DataGrid?
In WPF DataGrid (SfDataGrid), allows you to maintain the expanded state of the group while ungrouping and grouping the columns at runtime by handling the events CollectionChanged, GroupExpanded and GroupCollapsed.
public Dictionary<string, bool> GroupStates = new Dictionary<string, bool>();
public MainWindow()
{
InitializeComponent();
this.dataGrid.Loaded += OnDataGrid_Loaded;
}
private void OnDataGrid_Loaded(object sender, RoutedEventArgs e)
{
this.dataGrid.View.CollectionChanged += OnView_CollectionChanged;
this.dataGrid.GroupExpanded += OnDataGrid_GroupExpanded;
this.dataGrid.GroupCollapsed += OnDataGrid_GroupCollapsed;
}
private void OnDataGrid_GroupCollapsed(object sender, GroupChangedEventArgs e)
{
GroupStates[e.Group.Key.ToString()] = false;
}
private void OnDataGrid_GroupExpanded(object sender, GroupChangedEventArgs e)
{
GroupStates[e.Group.Key.ToString()] = true;
}
private void OnView_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
var collectionViewWrapper = sender as GridQueryableCollectionViewWrapper;
if (collectionViewWrapper != null)
{
if (collectionViewWrapper.Groups != null && collectionViewWrapper.Groups.Count > 0)
{
foreach (var group in collectionViewWrapper.Groups)
{
var grp = group as Group;
var key = grp.Key.ToString();
if (GroupStates.ContainsKey(key))
{
grp.IsExpanded = GroupStates[key];
while (!grp.IsBottomLevel)
{
var innergroups = grp.Groups;
if (innergroups != null && innergroups.Count > 0)
{
foreach (var innerGroup in innergroups)
{
if (GroupStates.ContainsKey(innerGroup.Key.ToString()))
innerGroup.IsExpanded = GroupStates[innerGroup.Key.ToString()];
else
GroupStates.Add(innerGroup.Key.ToString(), innerGroup.IsExpanded);
grp = innerGroup;
}
}
}
}
else
{
GroupStates.Add(key, grp.IsExpanded);
}
}
}
}
}
Take a moment to peruse the WPF DataGrid - Grouping documentation, where you can find about grouping in DataGrid with code examples.
Conclusion
I hope you enjoyed learning about how to maintain group expanded states in DataGrid.
You can refer to our WPF DataGrid feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications. You can also explore our WPF DataGrid example to understand how to create and manipulate data.
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