The WPF DataGrid has columns of type Text, Hyperlink, CheckBox, and ComboBox. If these column types do not fulfill your needs, either in read-only mode or when the cells are in edit mode, then you can define your own column type using templates. Users of the ASP.NET GridView will find this approach very familiar; you simply define a DataTemplate for rendering https://traderoom.info/ your data in read-only or edit mode. Handling delete operations is relatively straightforward, but how about updates or insertions? You might think that the same approach can be used, the NotifyCollectionChangedEventArgs.Action property does include Add operations; however, this event is not fired when the items within the collection are updated.
Statistics Rows and Summary Rows
The templated control which displays the error indicator is a child of the DataGridRow; therefore, we can obtain the validation errors from the row via a FindAncestor RelativeSource binding. When a user deletes a row with the DataGrid control, the CollectionChanged event is fired on the bound collection. In the event handler, we invoke the DAL DeleteCustomer method with the wrapped data object passed as the parameter. An alternative method for providing data to your controls is through the use of an ObjectDataProvider.
Implementation of Filtering Functionality
DataGridCollectionView class is essentially a collection, with some useful functionality built into it allowing Filtering, Grouping and Sorting. Finally, here are the two filtering methods, the first is the one that applies the filter by aggregating all predicates, the second is the search method for all popups. The code for dates works the same, except that the list of items is retrieved by the method GetAllItemsTree of the class FilterCommon. Each PopUp contains a search TextBox to filter the items, this functionality requires a specially dedicated filter, again ICollectionView is used.
Use saved searches to filter your results more quickly
A popular alternative to the previous example, where exceptions are thrown on the property setters of the data objects, is the use of the IDataErrorInfo interface. Objects that implement this interface are validated on demand, rather than each time their state changes. For a discussion of how this can make your business objects more useable, the article Fort Knox Business Objects makes interesting reading. They also have the advantage that they are able to validate state which depends on multiple properties; there is clearly a synergy here with BindingGroups.
Custom type columns can also be filtered if they provide a TypeConverter (from string) and implement IComparable. The normal datagrid included in the Plus Edition only is a rock-solid, high performance product with zero-lag data virtualization, the ability to handle large datasets, and with many core features. Xceed offers an advanced version of this datagrid with certain added features. You can purchase it separately, or try it for 45 days by clicking the ‘Try it now’ button here, but it is also included in the Xceed Business Suite for WPF as well.
Interestingly, the DatePicker picks up the current culture, whereas the TextBlock binding does not (yes, I live in the UK!). The WPF DataGrid can be styled in a highly flexible manner by applying Styles or Templates in the same way as for all of the other WPF controls. Many of the grid’s properties such as CellStyle and RowStyle are quite obvious. Rather than exhaustively cover all the various styling properties, this section will cover some of the DataGrid specific features, and also how to style some of the more tricky parts of the grid.
This example demonstrates how to use a DataGrid to perform CRUD operations via binding where the database integration is decoupled via a Data Access Layer (DAL). However, please note that any exception that occurs when the data is being updated is not being handled, which will result in the in-memory DataTable no longer being synchronized with the database. The complete example above can be found in the DataSetCRUDExample class which shows how a CRUD interface can be created for a DataSet with a few lines of code. While waiting for the value to arrive, the binding reports the value set on the FallbackValue property, if one is available, or the default value of the binding target property.
The following code snippet shows how the CustomerObjectDataProvider (which is defined as an ObjectDataProvider in the XAML) constructs an ObservableCollection of CustomerUIObjects. These UI objects simply wrap their data object counterparts in order to expose the same properties. The DistinctValuesConstraint property can also be set to determine if the distinct values are to be filtered according to the result of previous auto-filtering operations. The example in the attached source code presents a UI for editing the Customer table.
- In the event handler, we invoke the DAL DeleteCustomer method with the wrapped data object passed as the parameter.
- Improve performance and reduce load times for very large data sets with on-demand loading virtual mode, where data is only retrieved as the user scrolls, or paging, where data is loaded in segments.
- The two methods SaveDataGridLayoutToFile(…) and RestoreDataGridLayoutFromFile(…) for saving and restoring the data grid layout correspondingly are defined within static DataGridColumnManipulationBehavior static class.
- However, in most of the applications, we define columns, their types and bind to data source properties.
- For the Name property, I’ve used a simple text based column, so the most interesting part of this example comes with the Birthday column, where I’ve used a DataGridTemplateColumn with a DatePicker control inside of it.
Probably, one of the most frequent uses of a DataGrid is to provide the user with CRUD functions (create, read, update, delete) for managing a persistent data source. This example describes how to connect a Typed DataSet to the DataGrid in such a way that row modifications, deletions, and insertions are written to the database. The settings of a grid and its elements can be persisted and re-applied using the SaveUserSettings and LoadUserSettings methods, respectively. By default, column widths, visibility, positions, and fixed-column counts as well as grouping and sorting criteria are persisted; merged columns, their positions, and their visibility can also be persisted. However, these settings can be modified when calling the SaveUserSettings and LoadUserSettings methods. The FilterRow class represents a row in which values can be entered to filter the items in the corresponding columns.
Filter data with the row filter or an intuitive, built-in, Excel-inspired filtering UI. We convert the column collection into a collection of ColumnSerializableData objects and then save it to a file using XmlSerializationUtils.SerializeToFile(…) method. Then, I use various attached properties and behaviors to wire the filtering behavior, classes that define the look and feel of the text box and whether the TextBox is visible or enabled. Defined within NP.Avalonia Visuals package, in order to save the layout of the DataGrid (which we pass as the first argument to the static method) into file “MyGridLayoutFile.xml” which we pass as the second argument.
Demo code is located within NP.Ava.Demos repository, under NP.Demos.VisualSamples/NP.Demos.AdvancedDataGridDemo project. This article presents a sample demonstrating how to use those advanced features. Avalonia has only recently become production ready and because of that, the major 3rd party component providers like Telerik, DevExpress or Infragistics still have not released the components for Avalonia. I wrote extensively about Avalonia on CodeProject and produced several Avalonia based packages/frameworks also described in my CodeProject articles. Aggregate performs an operation on each element of the list taking into account the operations which have preceded. The presentation as a checkbox depends on the field type, DateTime for the TreeView and all other types for the ListBox.
The View must be a valid instance or subclass of TableView (ex. TableFlowView, TreeGridflowView). The DataGridControl class also exposes the ExportToXps method, which allows a grid to be exported as an XPS document. The StatRow class represents a row that can be used to display statistical results.
As you can see, there are no UI framework specific interfaces or classes (such as ObservableCollection) exposed by the DAL. The problem here is how to bind the customers returned by ICustomerDataAccess.GetCustomers to our DataGrid and ensure that changes are synchronised https://traderoom.info/displaying-data-in-tables-with-wpf-s-datagrid/ with the database. Any updates / deletions to the Customer or Order rows are written to the database. However, the interface is a little peculiar in that when inserting a new order row via the bottom DataGrid, you have to type in the related CustomerID.
Cells with identical text can automatically be displayed as one larger horizontal or vertical cell (or both). Cells can also be merged programmatically to display their content in a combined way (as shown by the City and Country columns in the image below). The two methods SaveDataGridLayoutToFile(…) and RestoreDataGridLayoutFromFile(…) for saving and restoring the data grid layout correspondingly are defined within static DataGridColumnManipulationBehavior static class. The standard validation error indicator is a red exclamation mark which is displayed at the left hand side of the row. The DataGridRow has a ValidationErrorTemplate which defines the appearance of this indicator. With the example given below, the exclamation mark is rendered within a red circle in order to give it a more striking appearance.
Easily export the WPF DataGrid control to various file formats such as Excel, PDF, or CSV. This is supported when the ItemsSource is derived from the ISupportIncrementalLoading interface. Search and highlight text in the WPF DataGrid and filter records based on the search text. Quickly print and export the WPF DataGrid to Excel, CSV, and PDF file formats. Once these lists have been retrieved (checkedItems and uncheckedItems), we must test whether any filtered items have again been checked by an Intersection between checkedItems and previousFilteredItems. Except and Intersect are Linq methods, here is a diagram which explains how these two operations work.