Description

Closes #6042

This pull request introduces a new exporter architecture for the DataGrid component.

As part of this architecture, I've also included two example supported formats

• Csv – a text-based format that is bundled in the Blazorise.DataGrid package.
• Bson – a binary format that is simple to work with and demonstrates external extensibility. It requires an additional dependency and is implemented in a separate project (Blazorise.DataGrid.Exporters). (This is where Excel exporters should go too).

While the new architecture is not small, it enables a powerful level of extensibility. Creating a CSV exporter, for example, could be done with much less code — but the purpose of this system is to ensure external exporters can be plugged into DataGrid easily.

With this architecture, no changes are needed in the Blazorise.DataGrid core codebase to support new exporters. A developer only needs to implement a single abstract class, focusing purely on the core export logic and options. Thanks to these design choices, the boilerplate for creating a new exporter (e.g. a potential JSON exporter) is reduced to a minimum (see the BsonToFileExporter).

While developing the architecture, I also re-evaluated what "export" should mean in the DataGrid context. It doesn't have to mean only exporting to a file — it can also mean exporting to a string (TextExporter), the clipboard, or any other target. Currently, we support 3 targets:

• File
• Clipboard
• Text (in-memory string)

This concept of "targets" opens up future extensibility such as:

• API-based export
• Printer
• Email or sharing
• Chat/Telegram integration

(Many of these could work with the simple TextTarget or minor variations of it, so I din't go much deeper)

Nomenclature

• Target: The destination where exported DataGrid content ends up (File, Clipboard, Text).
• Format: The format in which data is encoded (CSV, BSON, XML, etc.).
• Exporter: A combination of format and target, e.g. CsvToFileExporter. This is why the Csv directory contains multiple files — it supports multiple targets.

Getting data from DataGrid

This area still needs improvement, as my knowledge of the full DataGrid capabilities is limited. Currently, only columns with a defined Field are exported, and the value is either formatted (for text) or raw (for binary).

One potential future enhancement:
A property like BaseDataGridColumn.Func<object, object> ExportValue could be used to customize how each column is exported — giving the developer full control per column.

The data passed to exporters is structured as a List<List<object>> or List<List<string>>, depending on whether the export is binary or text-based.

Usage

As simple as:

// Simple export to CSV with default options
dataGridRef.Export(new CsvToFileExporter());

// Copy to clipboard without headers
dataGridRef.Export(new CsvToClipboardExporter(new() { ExportHeader = false }));

// Export to CSV file with a custom file name and only the first 3 rows
dataGridRef.Export(
    new CsvToFileExporter(new() { FileNameNoExtension = "custom-csv-file" }),
    new DataGridExportOptions { NumberOfRows = 3 }
);

// Bson export (defined in an external project)
dataGridRef.Export(new BsonToFileExporter());

As shown above, only one public method in DataGrid.razor.cs is needed to support all export formats and targets.

• This PR does not include UI changes (e.g. export button). That could come in a future PR.
• Blazorise.DataGrid.Exporters is an external test project designed to validate the extensibility of the exporter system. It serves as a foundation for future projects where we'll support additional exporters that require external dependencies (e.g., Excel). It can be merged in this test form - it does nothing wrong.