I have a WPF application using a WPF-Datagrid. I can click on the column header to sort columns, which works automatically. What I want is to programatically select a column at program start which is then sorted. Or to put it another way: I want to pretend a user has clicked the column header, but do it programatically, the MVVM way, omitting changes in the code behind. Is there any solution for that?
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So, you still want the user to click on the column header but the sorting code be in a view model instead?Timothy Ghanem– Timothy Ghanem2016-06-01 10:05:55 +00:00Commented Jun 1, 2016 at 10:05
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Timothy, no, I guess you missunderstood: I want the sorting performed programatically without the requirement that a user has pressed the column header. Or put it another way: a default-sorting for my datagrid. And yes, with the column header showing the correct sorting direction.Erik– Erik2016-06-01 10:59:03 +00:00Commented Jun 1, 2016 at 10:59
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2 Answers
I guess the "MVVM Way" of doing this is binding your DataGrid to a CollectionView which represents your objects collection and allows you to manage sorting via SortDescription property.
For example in your viewmodel you have a collection of objects:
private ObservableCollection<Entity> _entityCollection = null;
public ObservableCollection<Entity> EntityCollection
{
get
{
return _entityCollection;
}
set
{
_entityCollection = value;
RaisePropertyChanged("EntityCollection");
RaisePropertyChanged("CollectionView");
}
}
Note the RaisePropertyChanged("CollectionView") above: when your collection changes, the view should be notified that the collectionview has changed as well.
So instead of binding your datagrid directly to collection you define a read-only collectionview property like this:
private CollectionView _collectionView = null;
public CollectionView CollectionView
{
get
{
_collectionView = (CollectionView)CollectionViewSource.GetDefaultView(EntityCollection);
if (_collectionView != null)
_collectionView.SortDescriptions.Add(new SortDescription("PropertyName", ListSortDirection.Ascending));
return _collectionView;
}
}
Then you bind your datagrid:
<DataGrid ItemsSource="{Binding Path=CollectionView}">
Finally if you want to change the property by which the collection is sorted you should clear the collectionview's sortdescriptions and add a new one like this:
_collectionView.SortDescriptions.Clear();
_collectionView.SortDescriptions.Add(new SortDescription("NewPropertyName", ListSortDirection.Ascending));
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Tech vidhyarthi
I have grid with column having check box. I want to display selected items in the checkbox on top. I am trying to implement this way. But sorting is not working for me @Alex
you can do it by using Linq query if you have list and if you are using DataTables the you can use MyRows = myTable.Select(strExpr, strSort);
First you have to select the column you want to sort with and then at viewmodel you can can use either LINQ ormyTable.Select(strExpr, strSort)
Example code
switch(columnname)
{
case "name":
break;
case "FatherName"
break;
}
