I have a Xceed Datagrid whose ItemsSource is CollectionViewSource defined in XAML. Whenever grid is updated, only the row which is in focus doesn't show updated values (revert back to original values) but all of other rows are updated. If I directly bound the grid to a Collection in ViewModel then everything works fine. The problem is only when, CollectionViewSource comes into picture. Any help is appreciated.
Can you try using the DataGridCollectionViewSource instead of a CollectionViewSource. By using this, you will reap the benefits of the DataGrid such as built in filtering, sorting, grouping, etc. An example from their documentation:
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">
<Grid.Resources>
<xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
Source="{Binding Source={x:Static Application.Current},
Path=Orders}"/>
</Grid.Resources>
<xcdg:DataGridControl x:Name="OrdersGrid"
ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
</Grid>
I got solution...
grid.CurrentItem = null
Related
WPF, MVVM
I'm finding that if I use a CollectionViewSource with my ComboBox, when I close the window, an extra call to the SelectedValue Setter is executing, if SelectedValue is bound to a string property. If I set the ItemsSource binding directly to the VM, this call does not happen. The extra call is causing values to change in the VM, resulting in incorrect data. I have other ComboBoxes setup the same way, but they bind to integer values.
CollectionViewSource definition:
<CollectionViewSource x:Key="AllClientsSource" Source="{Binding AllClients}" >
<CollectionViewSource.SortDescriptions>
<scm:SortDescription PropertyName="ClientName" />
</CollectionViewSource.SortDescriptions>
</CollectionViewSource>
ComboBox with CollectionViewSource:
<ComboBox Grid.Column="2"
ItemsSource="{Binding Source={StaticResource AllClientsSource}}"
DisplayMemberPath="ClientName" SelectedValuePath="ClientId"
SelectedValue="{Binding Path=ClientId}"
Visibility="{Binding Path=IsEditingPlan, Converter={StaticResource BoolVisibility}}" />
ComboBox direct to VM (Forgoing sorting):
<ComboBox Grid.Column="2" ItemsSource="{Binding AllClients}"
DisplayMemberPath="ClientName" SelectedValuePath="ClientId"
SelectedValue="{Binding Path=ClientId}"
Visibility="{Binding Path=IsEditingPlan, Converter={StaticResource BoolVisibility}}" />
Can anyone tell me why there is an extra setter call using the CollectionViewSource? What's different about the string binding? Is there a way to properly work around it?
EDIT: I tried changing it up and using the SelectItem property on the ComboBox. Same result. So it seems that if the item is a scalar data type, it works as expected. If it's an object, you get an extra setter call with a null value. Again, if I remove the CollectionViewSource from the equation, it works as expected.
EDIT, AGAIN: I added a link to a sample project that illustrates the issue. Targets .Net 4.5.
Run the project.
Click to display View One
Select a Client and the client's name will display on the right.
Click to display View Two
Go back to View One - Note that the selected client is no longer selected.
Click to display View Three
Select a Region and the region's name is displayed on the right.
Go back to View Two
Go back to View Three - Note that the selected region is still selected.
The only difference between the views is that One and Two use a CollectionViewSource. Three binds directly to the ViewModel. When you move to a new tab from One or Two, the setter for the selected item is getting called with a null value. Why? What's the best work-around?
Thanks.
Apparently this is caused when the CollectionViewSource is removed from the visual tree... I moved the CollectionViewSource to the ViewModel and exposed it as a property and the issue is effectively worked-around.
I'v a wizard style application that uses pages and the user can navigate between them either by Next and Previous buttons or by using a navigation bar to directely access certain pages.
On one page (i'll call it "grid page")i have a DataGrid bound to a DataTable. There is some initial data in the DataTable, but using the DataGrid the user can add, edit and delete rows as he wishes.
On the next page (i'll call i "combo box page") have a ComboBox which is bound to the same DataTable as the DataGrid on the grid page.
Both pages use the same object as data context.
If i jump to the combo box page directly everything works fine, the combo box has an entry for each row in the DataTable like it's supposed to be. Now i navigate to the grid page and don't touch anything there and then go to the combo box page again. Now the ComboBox displays a new item, a NewItemPlaceholder. Obviously this happens because the DataGrid has UserCanAddRows set to true and thus displays a placeholder row for a new item. But this should only concern the DataGrid and not the bound DataTable, so in my eyes this is a bug, or at least an absolutely horrible design.
Of course i don't want the NewItemPlaceholder in my ComboBox (and selecting it causes a lot of problems). So how can i prevent it from being displayed in the ComboBox?
Update: In the meantime i found out the placeholder item isn't in the DataTable as a row, which makes it even stranger, unless there is a flag in a DataTable that says "there is a NewItemPlaceholder in this table" but isn't a row itself. Additionally when i register to the Initialized event of the ComboBox i have the 2 items i'm looking for, when i register to the Loaded event i have the NewItemPlaceholder as well, so it must be added somewhere between those 2 events.
Use a CollectionViewSource. The problem occurs when more than one control shares the same view of a collection such as when a collection is bound in one case to a DataGrid and in another to the ComboBox. If the DataGrid allows the user to add items (i.e., the DataGrid's CanUserAddRows is true), the NewItemPlaceholder may have been added to the view. Try something like
<UserControl >
<UserControl.Resources >
<CollectionViewSource Source="{Binding MyCollection}"
x:Key="SourceWithoutNewItemPlaceholder" />
</UserControl.Resources>
<Grid Name="LayoutGrid" >
<ComboBox ItemsSource={Binding Source={StaticResource SourceWithoutNewItemPlaceholder}} >
</Grid>
</UserControl>
After several failed attempts i found 2 solutions:
1) In the Loaded event of the page i make a binding in the code behind, not to the DataTable itself, but to a DataTable.ToList. If i do it that way the NewItemPlaceholder won't show up.
2) In the view model i make a new property which returns the DataTable.ToList and bind to it. This way i can do the binding in XAML.
Just for reference, methods that don't work: Filter property on the ComboBox throws a NotSupportedException, seems the DataTable doesn't support this. Deleting the NewItemPlaceholder in the Loaded event of the ComboBox doesn't work either because you can't delete items when an ItemsSource is set. Removing the NewPlaceHolderItem when leaving the page with the data grid doesn't work either, because i can't find where it is (it's not in the DataTable or the View of the DataTable)
Use a CollectionViewSource to bind one control(Combobox) and collection property defined in ViewModel to bind another control (Datagrid).
Property in ViewModel :
private List<Rate> _rate = new List<Rate>();
public List<Rate> RatePlans
{
get { return _rate; }
set
{
_rate = value;
OnPropertyChanged("RatePlans");
}
}
Then in XAML :
<UserControl >
<UserControl.Resources >
<CollectionViewSource Source="{Binding RatePlans}" x:Key="RatesSource" />
</UserControl.Resources>
<Grid Name="LayoutGrid">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<ComboBox Grid.Row="0" DisplayMemberPath="RatePlanName" ItemsSource="{Binding Source={StaticResource RatesSource}}" HorizontalAlignment="Stretch"/>
<DataGrid Grid.Row="1" HorizontalAlignment="Stretch" CanUserAddRows="True" AutoGenerateColumns="False" ItemsSource="{Binding RatePlans}">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding RatePlanName}" Header="Rate Plan" />
<DataGridTextColumn Binding="{Binding RoomType}" Header="Room Type" />
<DataGridTextColumn Binding="{Binding Price}" Header="Price"/>
</DataGrid.Columns>
</DataGrid>
</Grid>
</UserControl>
I want to protect some rows of a DataGrid to be protected from deletion by the user, although the property CanUserDeleteRows is set to true.
Is there a possibility to protect some rows, hopefully through a databinding or a trigger? The ItemsSource is bound to an ObservableCollection of T.
If you have a property on your bound objects that can be used to determine if the current row can be deleted , like 'IsDeleteEnabled', then you can bind the DataGrid's CanUserDeleteRows property to SelectedItem.IsDeleteEnabled.
For example,
<DataGrid Name="dataGrid1"
CanUserDeleteRows="{Binding ElementName=dataGrid1, Path=SelectedItem.IsDeleteEnabled}"
Never done this with a DataGrid. Usually, when I need to control something like this, I use a ListBox and a DataTemplate with a Grid within to give it the idea of a Grid or a ListView with a GridView in the template because they both give you more control over the interaction.
A shot in the dark, since you're binding, you could use a DataGridTemplateColumn.CellEditingTemplate and make your own Delete button/text which is visible or enabled based off logic within your binding object. Maybe something like this (I didn't test this, but it should be a direction you can head)?
<dg:DataGridTemplateColumn Header="Action">
<dg:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Text Content="Delete" />
</DataTemplate>
</dg:DataGridTemplateColumn.CellTemplate>
<dg:DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<ButtonEnabled="{Binding Path=IsDeleteEnabled, Mode=OneWay}" Content="Delete" Command="{Binding Path=DeleteMe}" />
</DataTemplate>
</dg:DataGridTemplateColumn.CellEditingTemplate>
</dg:DataGridTemplateColumn>
Using this method, since the command is bound to the individual object, you would probably have to raise an event your screen's ViewModel handles to remove that row from the ObservableCollection.
Again, not sure if this is the best way, but it's my 10 minute stab at it. So if it's horrible, please don't vote me down too much.
I have a DataGrid bound to a CollectionViewSource in XAML.
<Window.Resources>
<local:MainWindowViewModel x:Key="ViewModel"/>
<CollectionViewSource x:Key="cvsEntries"
Source="{Binding LogEntriesStore,
Source={StaticResource ViewModel}}"/>
</Window.Resources>
LogEntriesStore is an ObservableCollection (LogEntry is a DTO that's not important in this discussion)
The DataGrid is declared as:
<DataGrid AutoGenerateColumns="False"
Margin="0"
Name="dataGrid1"
ItemsSource="{Binding Source={StaticResource cvsEntries}}"
IsReadOnly="True">
Now I have context menus on various cells in this DataGrid, to kick off a request for filtering. Right click on a cell, and pick filter to filter all the rows, and show only this particular value.
The MVVM gets the request to filter, but the now the tricky bit. How do I set the filter on the CollectionViewSource?
(as an aside -- this would have been a walk in the park with a Silverlight PagedCollectionView but that doesn't seem to be available in WPF, is that right?)
Very simple. You just need to move the collection view inside the view model:
In MainWindowViewModel define a property of type ICollectionView:
public ICollectionView LogEntriesStoreView { get; private set; }
Right after you have initialized the LogEntriesStore property, you need to initialize the LogEntriesStoreView property with the following code:
LogEntriesStoreView = CollectionViewSource.GetDefaultView(LogEntriesStore);
Then you need to remove the CollectionViewSource from XAML and modify the ItemsSource binding to point to the newly created collection view property:
<DataGrid AutoGenerateColumns="False"
Margin="0"
Name="dataGrid1"
ItemsSource="{Binding LogEntriesStoreView, Source={StaticResource ViewModel}}"
IsReadOnly="True">
That's it. Now you have the access to the collection view inside your view model, where you can modify the filter.
There are several solutions to your problem, but in my opinion, the best solutions are the ones which uses only styles with the standard WPF DataGrid control without inventing a new inherited DataGird type or depending on another third-party control. The followings are the best solutions I found:
Option 1: which I personally use: Automatic WPF Toolkit DataGrid Filtering
Option 2: Auto-filter for Microsoft WPF DataGrid
I have a datagrid. A column of the datagrid is a simple <DataGridTemplateColumn> with its CellTemplate containing a <DataTemplate> which contains a <ComboBox> such as
<my:DataGrid Name="dataGridMain" AutoGenerateColumns="False">
<my:DataGrid.Columns>
<my:DataGridTemplateColumn Header="Food" >
<my:DataGridTemplateColumn.CellTemplate >
<DataTemplate>
<ComboBox Name="comboDataTemplate"
Text="{Binding Path=Food,
Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding Source={StaticResource resFoodLookups}}"
DisplayMemberPath="FoodName"
SelectedValuePath="FoodID" IsEditable="True" />
</DataTemplate>
</my:DataGridTemplateColumn.CellTemplate>
</my:DataGridTemplateColumn>
</my:DataGrid.Columns>
</my:DataGrid>
All is working fine. Each combobox is bound to a static list due to the ItemsSource="{Binding Source={StaticResource resFoodLookups}}" statement.
But my requirement is that this list will change from row-to-row.
That is: each time a user types a new entry in the combobox list on one row, I want to have it available in the selection on the next row.
Basically, I want to create a new list for the user each time the user inserts a new word in the combobox on any of the rows. (The combobox is editable).
Now, I can wire up the "ItemsSource=..." at run-time, but I'm only able to do this once thus the <DataTemplate> propagates the 'same' list to 'all' the comboboxes on 'all' the rows.
My thoughts are that I need to change the ItemsSource=... property on an object-by-object basis on each combobox that is created in memory after the DataTemplate has created them - but I have no idea how to do this.
What you need to do is perform 2 way data binding to your the ItemsSource, this way when the ItemSource is updated in one of the combo boxes it will auto update your original collection and therefore your other combo boxes as well.
What I normally do is use the MVVM pattern. It is worth some research if you are not already using a particular pattern on your application.
Using it to solve your problem i would do the following:
Create a ViewModel (Lets call it MyViewModel) which has a collection of values called 'MyComboBoxItems' (It is important that you use ObservableCollection for the databinding to work)
When I create the Window/Control that contains your table, I also create an instance of MyViewModel and set its the Window.DataContext=myViewModelInstance
For your combobox binding use ItemsSource="{Binding Path=MyComboBoxItems, Mode=TwoWay}