Render table with Entity Framework

There are a number of tasks when for some reason it is more convenient to export data from databases to a PDF document without using the recently popular HTML to PDF conversion scheme.

This article will show you how to generate a PDF document using the Aspose.PDF for .NET.

Basics of generation PDF with Aspose.PDF

One of the most important classes in Aspose.PDF is a Document class. This class is a PDF rendering engine. To present a PDF structure, the Aspose.PDF library uses the Document-Page model, where:

• Document - contains the properties of the PDF document including page collection.
• Page - contains the properties of a specific page and various collections of elements associated with this page.

Therefore, to create a PDF document with Aspose.PDF, you should follow these steps:

1. Create the Document object.
2. Add the page (the Page object) for the Document object.
3. Create objects that are placed on the page (e.g. text fragment, table, etc.).
4. Add created items to the corresponding collection on the page (in our case it will be a paragraph collection).
5. Save the document as PDF file.

.NET Core 3.1

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTable()
{
    // Create PDF document
    using (var document = new Aspose.Pdf.Document
           {
               PageInfo = new Aspose.Pdf.PageInfo { Margin = new Aspose.Pdf.MarginInfo(28, 28, 28, 42) }
           })
    {
        // Add page
        var page = document.Pages.Add();

        var textFragment = new Aspose.Pdf.Text.TextFragment(reportTitle);

        var table = new Aspose.Pdf.Table
        {
            // .................................
        };

        page.Paragraphs.Add(textFragment);
        page.Paragraphs.Add(table);

        using (var streamOut = new MemoryStream())
        {
            // Save PDF document
            document.Save(streamOut);

            return new FileContentResult(streamOut.ToArray(), "application/pdf")
            {
                FileDownloadName = "tenants.pdf"
            };
        }
    }
}

.NET 8

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTable()
{
    // Create PDF document
    using var document = new Aspose.Pdf.Document
    {
        PageInfo = new Aspose.Pdf.PageInfo { Margin = new Aspose.Pdf.MarginInfo(28, 28, 28, 42) }
    };

    // Add page
    var page = document.Pages.Add();

    var textFragment = new Aspose.Pdf.Text.TextFragment(reportTitle);

    var table = new Aspose.Pdf.Table
    {
        // .................................
    };

    page.Paragraphs.Add(textFragment);
    page.Paragraphs.Add(table);

    using var streamOut = new MemoryStream();

    // Save PDF document
    document.Save(streamOut);

    return new FileContentResult(streamOut.ToArray(), "application/pdf")
    {
        FileDownloadName = "tenants.pdf"
    };
}

The most common problem is the output of data in a table format. The Table class is used to process tables. This class gives us the ability to create tables and place them in the document, using Rows and Cells. So, to create the table, you need to add the required number of rows and fill them with the appropriate number of cells.

The following example creates the table 4x10.

.NET Core 3.1

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTable()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_WorkingDocuments();

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Add page
        var page = document.Pages.Add();

        var table = new Aspose.Pdf.Table
        {
            // Set column auto widths of the table
            ColumnWidths = "25% 25% 25% 25%",

            // Set cell padding
            DefaultCellPadding = new Aspose.Pdf.MarginInfo(10, 5, 10, 5), // Left Bottom Right Top

            // Set the table border color as Green
            Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .5f, Aspose.Pdf.Color.Green),

            // Set the border for table cells as Black
            DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .2f, Aspose.Pdf.Color.Green),
        };

        for (var rowCount = 0; rowCount < 10; rowCount++)
        {
            // Add row to table
            var row = table.Rows.Add();

            // Add table cells
            for (int i = 0; i < 4; i++)
            {
                row.Cells.Add($"Cell ({i + 1}, {rowCount + 1})");
            }
        }

        // Add table object to first page of input document
        page.Paragraphs.Add(table);

        // Save PDF document
        document.Save(dataDir + "AddTable_out.pdf");
    }
}

.NET 8

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTable()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_WorkingDocuments();

    // Create PDF document
    using var document = new Aspose.Pdf.Document();

    // Add page
    var page = document.Pages.Add();

    var table = new Aspose.Pdf.Table
    {
        // Set column auto widths of the table
        ColumnWidths = "25% 25% 25% 25%",

        // Set cell padding
        DefaultCellPadding = new Aspose.Pdf.MarginInfo(10, 5, 10, 5), // Left Bottom Right Top

        // Set the table border color as Green
        Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .5f, Aspose.Pdf.Color.Green),

        // Set the border for table cells as Black
        DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .2f, Aspose.Pdf.Color.Green),
    };

    for (var rowCount = 0; rowCount < 10; rowCount++)
    {
        // Add row to table
        var row = table.Rows.Add();

        // Add table cells
        for (int i = 0; i < 4; i++)
        {
            row.Cells.Add($"Cell ({i + 1}, {rowCount + 1})");
        }
    }

    // Add table object to first page of input document
    page.Paragraphs.Add(table);

    // Save PDF document
    document.Save(dataDir + "AddTable_out.pdf");
}

When initializing the Table object, the minimal skin settings were used:

• ColumnWidths - width of columns (by default).
• DefaultCellPadding - the default fields for the table cell.
• Border - table frame attributes (style, thickness, color).
• DefaultCellBorder - attributes of the cell frame (style, thickness, color).

As a result, we get the table 4x10 with equal-width columns.

Exporting Data from ADO.NET Objects

The Table class provides methods for interacting with ADO.NET data sources - ImportDataTable and ImportDataView. The first method imports data from the DataTable, the second from the DataView. Premising that these objects are not very convenient for working in the MVC template, we will limit ourselves to a brief example. In this example (line 50), the ImportDataTable method is called and receives as parameters a DataTable instance and additional settings like the header flag and the initial position (rows/cols) for the data output.

.NET Core 3.1

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTable()
{
    // Create PDF document
    using (var document = new Aspose.Pdf.Document
    {
        PageInfo = new Aspose.Pdf.PageInfo { Margin = new Aspose.Pdf.MarginInfo(28, 28, 28, 42) }
    })
    {
        var table = new Aspose.Pdf.Table
        {
            // Set column widths of the table
            ColumnWidths = "25% 25% 25% 25%",
            // Set cell padding
            DefaultCellPadding = new Aspose.Pdf.MarginInfo(10, 5, 10, 5), // Left Bottom Right Top
            // Set the table border color as Green
            Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .5f, Aspose.Pdf.Color.Green),
            // Set the border for table cells as Black
            DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .2f, Aspose.Pdf.Color.Green),
        };

        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("config.json", false)
            .Build();

        var connectionString = configuration.GetSection("connectionString").Value;

        if (string.IsNullOrEmpty(connectionString))
        {
            throw new ArgumentException("No connection string in config.json");
        }

        var resultTable = new DataTable();

        using (var conn = new SqlConnection(connectionString))
        {
            const string sql = "SELECT * FROM Tennats";
            using (var cmd = new SqlCommand(sql, conn))
            {
                using (var adapter = new SqlDataAdapter(cmd))
                {
                    adapter.Fill(resultTable);
                }
            }
        }

        table.ImportDataTable(resultTable, true, 1, 1);

        // Add table object to first page of input document
        document.Pages[1].Paragraphs.Add(table);

        using (var streamOut = new MemoryStream())
        {
            // Save PDF document
            document.Save(streamOut);

            return new FileContentResult(streamOut.ToArray(), "application/pdf")
            {
                FileDownloadName = "demotable2.pdf"
            };
        }
    }
}

.NET 8

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTable()
{
    // Create PDF document
    using var document = new Aspose.Pdf.Document
    {
        PageInfo = new Aspose.Pdf.PageInfo { Margin = new Aspose.Pdf.MarginInfo(28, 28, 28, 42) }
    };

    var table = new Aspose.Pdf.Table
    {
        // Set column widths of the table
        ColumnWidths = "25% 25% 25% 25%",
        // Set cell padding
        DefaultCellPadding = new Aspose.Pdf.MarginInfo(10, 5, 10, 5), // Left Bottom Right Top
        // Set the table border color as Green
        Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .5f, Aspose.Pdf.Color.Green),
        // Set the border for table cells as Black
        DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, .2f, Aspose.Pdf.Color.Green),
    };

    var configuration = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("config.json", false)
        .Build();

    var connectionString = configuration.GetSection("connectionString").Value;

    if (string.IsNullOrEmpty(connectionString))
    {
        throw new ArgumentException("No connection string in config.json");
    }

    var resultTable = new DataTable();

    using var conn = new SqlConnection(connectionString);

    const string sql = "SELECT * FROM Tennats";

    using var cmd = new SqlCommand(sql, conn);

    using var adapter = new SqlDataAdapter(cmd);
    
    adapter.Fill(resultTable);

    table.ImportDataTable(resultTable, true, 1, 1);

    // Add table object to first page of input document
    document.Pages[1].Paragraphs.Add(table);

    using var streamOut = new MemoryStream();
    
    // Save PDF document
    document.Save(streamOut);

    return new FileContentResult(streamOut.ToArray(), "application/pdf")
    {
        PageInfo = new Aspose.Pdf.PageInfo { Margin = new Aspose.Pdf.MarginInfo(28, 28, 28, 42) }
    };
}

Exporting Data from the Entity Framework

More relevant for modern .NET is the import of data from ORM frameworks. In this case, it’s a good idea to extend the Table class with extension methods for importing data from a simple list or from the grouped data. Let’s give an example for one of the most popular ORMs - Entity Framework.

public static class PdfHelper
{
    private static void ImportEntityList<TSource>(this Aspose.Pdf.Table table, IList<TSource> data)
    {
        var headRow = table.Rows.Add();

        var props = typeof(TSource).GetProperties(BindingFlags.Public | BindingFlags.Instance);
        foreach (var prop in props)
        {
            headRow.Cells.Add(prop.GetCustomAttribute(typeof(DisplayAttribute)) is DisplayAttribute dd ? dd.Name : prop.Name);
        }

        foreach (var item in data)
        {
            // Add row to table
            var row = table.Rows.Add();
            // Add table cells
            foreach (var t in props)
            {
                var dataItem = t.GetValue(item, null);
                if (t.GetCustomAttribute(typeof(DataTypeAttribute)) is DataTypeAttribute dataType)
                    switch (dataType.DataType)
                    {

                        case DataType.Currency:
                            row.Cells.Add(string.Format("{0:C}", dataItem));
                            break;
                        case DataType.Date:
                            var dateTime = (DateTime)dataItem;
                            if (t.GetCustomAttribute(typeof(DisplayFormatAttribute)) is DisplayFormatAttribute df)
                            {
                                row.Cells.Add(string.IsNullOrEmpty(df.DataFormatString)
                                    ? dateTime.ToShortDateString()
                                    : string.Format(df.DataFormatString, dateTime));
                            }
                            break;
                        default:
                            row.Cells.Add(dataItem.ToString());
                            break;
                    }
                else
                {
                    row.Cells.Add(dataItem.ToString());
                }
            }
        }
    }

    private static void ImportGroupedData<TKey, TValue>(this Aspose.Pdf.Table table, IEnumerable<Models.GroupViewModel<TKey, TValue>> groupedData)
    {
        var headRow = table.Rows.Add();
        var props = typeof(TValue).GetProperties(BindingFlags.Public | BindingFlags.Instance);
        foreach (var prop in props)
        {
            headRow.Cells.Add(prop.GetCustomAttribute(typeof(DisplayAttribute)) is DisplayAttribute dd ? dd.Name : prop.Name);
        }

        foreach (var group in groupedData)
        {
            // Add group row to table
            var row = table.Rows.Add();
            var cell = row.Cells.Add(group.Key.ToString());
            cell.ColSpan = props.Length;
            cell.BackgroundColor = Aspose.Pdf.Color.DarkGray;
            cell.DefaultCellTextState.ForegroundColor = Aspose.Pdf.Color.White;

            foreach (var item in group.Values)
            {
                // Add data row to table
                var dataRow = table.Rows.Add();
                // Add cells
                foreach (var t in props)
                {
                    var dataItem = t.GetValue(item, null);

                    if (t.GetCustomAttribute(typeof(DataTypeAttribute)) is DataTypeAttribute dataType)
                        switch (dataType.DataType)
                        {
                            case DataType.Currency:
                                dataRow.Cells.Add(string.Format("{0:C}", dataItem));
                                break;
                            case DataType.Date:
                                var dateTime = (DateTime)dataItem;
                                if (t.GetCustomAttribute(typeof(DisplayFormatAttribute)) is DisplayFormatAttribute df)
                                {
                                    dataRow.Cells.Add(string.IsNullOrEmpty(df.DataFormatString)
                                        ? dateTime.ToShortDateString()
                                        : string.Format(df.DataFormatString, dateTime));
                                }
                                break;
                            default:
                                dataRow.Cells.Add(dataItem.ToString());
                                break;
                        }
                    else
                    {
                        dataRow.Cells.Add(dataItem.ToString());
                    }
                }
            }
        }
    }
}

The Data Annotations attributes are often used to describe models and help us to create the table. Therefore, the following table generation algorithm was chosen for ImportEntityList:

• lines 12-18: build a header row and add header cells according to the rule “If the DisplayAttribute is present, then take its value otherwise take the property name”.
• lines 50-53: build the data rows and add row cells according to the rule “If the attribute DataTypeAttribute is defined, then we check whether we need to make additional design settings for it, and otherwise just convert data to string and add to the cell;”.

In this example, additional customizations were made for DataType.Currency (lines 32-34) and DataType.Date (lines 35-43), but you can add others if necessary. The algorithm of the ImportGroupedData method is almost the same as the previous one. An additional GroupViewModel class is used, to store the grouped data.

using System.Collections.Generic;
public class GroupViewModel<K,T>
{
    public K Key;
    public IEnumerable<T> Values;
}

Since we process groups, first we generate a line for the key value (lines 66-71), and after it - the lines of this group.