Dynamic Columns in a WPF DataGrid Control Part 1- CodeProject
Troubleshooting a Decimal-data error in an RPGLE program using embedded SQL. This guide covers various join strategies and indexing techniques for efficient data retrieval. Troubleshooting a Spring Boot pagination issue with Pageable in Spring Boot 3.1.0 and Hibernate 6.2. Data retrieval returns the entire dataset instead of the requested page.
Method analyses necessary changes and remove or add rows and remove or add cell view models to rows. Asynchronous method allows to keep application responsible, and using cancellation token allows to cancel updating if control size is changed again. Dynamic grid is implemented as user control that contains DataGrid control bound to observable collection of collections of cell view models. In this implementation collection of cells is recreated each time if grid width or grid height is changed, and it leads to some application pauses. In the following post this issue is solved with asynchronous method that updates cell array.
This example shows how to update the price of a specific product in the Products table. It’s crucial to include a WHERE clause to specify which record to update, preventing accidental modifications.
Also, I don’t really need to use specifically the DataGrid, as this will be simple table of strings for preview only – it may be as well displayed, say, inside Grid with ItemsControl – I just need to provide a view with columns and rows. Learn how to resolve IBM iSeries database update issues and iDB2Exception errors without altering the connection string’s library list. Explore DB2 Row Level Security and how access controls propagate across foreign key relationships in relational databases. Learn how to perform efficient set membership checks using SQL CASE WHEN IN statements. This example demonstrates the use of stored procedures for encapsulating data manipulation logic.
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Instead of individual updates for each table, we can use a single, unified approach. This involves creating a view or stored procedure that combines data from relevant tables, simplifying data access and manipulation. The WPF application then interacts with this consolidated data source. This streamlined approach minimizes the number of database interactions, leading to improved performance, especially when dealing with large datasets. The use of parameterized queries further enhances security by preventing SQL injection vulnerabilities. By centralizing data access through a well-defined interface, the application’s maintainability is greatly improved.
Update collection of cell view models
- Since there is no such property in the UserTable definition, another solution has to be implemented.
- Also, other implementation for cells could be used; for example, 2-dimensional array of cells ICellViewModels works well.
- Within a Table object, Rows must be contained in a TableRowGroup element.
- Learn how to efficiently update NULL values in SQL tables using various techniques.
The drawback of this solution is that GUI components spilled over into the ViewModel layer. In the next article, I will show a solution that implements the same application, but with a more strict separation of business logic and GUI controls into their respective layers. As an added bonus (and to prevent extra state logic) I added the functionality that the CheckBox control is not shown in the user data grid new item row. The DataGridCheckBoxColumn style has to be modified, and the Visibility flag of the CheckBox has to be set, depending on the contents of the DataGridCell. If the data row is the new item row, then it has a NewItemPlaceHolder. A converter is used to get this information and it is mapped to the CheckBox’s Visibility flag.
View model of dynamic data grid contains cell, view and grid sizes, data model for cell set, and collection of collections of cell view models. Actually, it is not a clear approach from the point of MVVM pattern, as view model should know nothing about view, but it is realized in accurate way via binding and attached properties. Grid size, i.e. number of rows and columns, is calculated as view size divided by cell size. As https://traderoom.info/displaying-data-in-tables-with-wpf-s-datagrid/ number of rows and columns are integers, real size of cells on the view could not equal to values of cell width and height. After new cells set is created, collection of cell view models should be updated.
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DataGrid is a data shaping component that allows the end user to manage the data and also display the data on the screen. It provides a feature called AutoGenerateColumns that automatically generates columns. Learn how to efficiently update NULL values in SQL tables using various techniques. This guide covers SQL NULL value update strategies and best practices. Learn to efficiently combine data from two SQL tables using various techniques including joins and conditional logic. Learn to create a dynamic PostgreSQL pivot table for summarizing patient treatments handling varying medication counts up to five and ordering alphabetically.
Using the Code
As you can see, I dynamically create a Binding, and use the index of the column in my model as the binding path. When building an application, I might not have the luxury of creating model classes to represent the objects I’ll be rendering on screen, because they are dynamic. If I don’t know the shape of my data, I can use a meta model (a model of the final model) to represent it.
Updating NULL Values in SQL Tables: A Comprehensive Guide
This involves defining constraints on database columns, such as data types, lengths, and nullability, and implementing validation logic in the WPF application before submitting data to the database. This two-pronged approach prevents invalid data from entering the system, maintaining data integrity and enhancing the overall reliability of the application. The combination of database constraints and application-level validation provides a robust defense against invalid data, minimizing errors and ensuring data accuracy. Regular testing and validation procedures further solidify data integrity and contribute to a more stable and reliable application.
Also, other implementation for cells could be used; for example, 2-dimensional array of cells ICellViewModels works well. Note that the XAML markup for the view contains only an empty DataGrid and the columns and bindings are defined in code. This is perfectly acceptable and does not break the MVVM pattern since all code is view related. The MVVM design pattern is about separating application logic from your view logic and not necessarily about eliminating code out of the views. The reason why this is done in C# code instead of static XAML markup is of course that the number of groups (columns) is dynamic and may vary over time. For example, if you add another row to the Group database table, you want another column representing this new group to show up in the DataGrid without any changes to the code.
The DataGridCheckBoxColumn binds the check box control to a (nullable) boolean property of the data in the row that it is displaying. In this case, it would be a boolean property in the user data row, which represents the user to role assignment. Since there is no such property in the UserTable definition, another solution has to be implemented. Instead of binding to the check box control, a value converter is instantiated and bound to the DataGridCell that will contain the CheckBox control. The Binding definition in the AddRoleColumn method shown above contains an assignment to the value converter. The relative source of the bound control is set to the DataGridCell, found as an ancestor of the CheckBox control (the binding is defined on the CheckBox level).
Note however that as a converter is not part of the visual tree, it doesn’t have any DataContext and this means that you have to get or inherit this from somewhere. You can read this external article published on the CodeProject for some ways of doing this if you decide to take this approach. Dynamic grid is implemented as user control that contains DataGrid control bound to observable collection of collections of cell view models. This section delves into efficient techniques for manipulating data within a SQL Server database, seamlessly integrated with a WPF application using C#.
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