MergeRows.vb
''
'' This code is part of GrapeCity Documents for PDF samples.
'' Copyright (c) GrapeCity, Inc. All rights reserved.
''
Imports System.IO
Imports System.Drawing
Imports System.Text
Imports System.Data
Imports System.Linq
Imports System.Collections.Generic
Imports GrapeCity.Documents.Pdf
Imports GrapeCity.Documents.Text
Imports GrapeCity.Documents.Html

'' This sample shows how to build and render a table-based report
'' grouped by the first column, with that column's cells with same
'' values merged.
'' This sample uses a JavaScript code in the HTML to actually
'' merge the cells, demonstrating the use of JavaScript when
'' rendering HTML to PDF.
'' Note that the sample limits the number of rows so that
'' the whole table fits on a single page.
''
'' Please see notes in comments at the top of HelloWorldHtml
'' sample code for details on adding GcHtml to your projects.
Public Class MergeRows
    Sub CreatePDF(ByVal stream As Stream)
        Const TTAG = "___TABLE___"

        '' HTML page template:
        Const tableTpl =
            "<!DOCTYPE html>" +
            "<html>" +
            "<head>" +
            "<style>" +
            "" +
            "html * {" +
            "  font-family: 'Trebuchet MS', Arial, Helvetica, sans-serif !important;" +
            "}" +
            "" +
            "h1 {" +
            "  color: #1a5276;" +
            "  background-color: #d2b4de;" +
            "  text-align: center;" +
            "  padding: 6px;" +
            "}" +
            "" +
            "thead {display: table-header-group;}" +
            "" +
            "#products {" +
            "  font-family: 'Trebuchet MS', Arial, Helvetica, sans-serif;" +
            "  border-collapse: collapse;" +
            "  width: 100%;" +
            "}" +
            "" +
            "#products td, #products th {" +
            "  border: 1px solid #ddd;" +
            "  padding: 8px;" +
            "}" +
            "" +
            "#products tr:hover {background-color: #ddd;}" +
            "" +
            "#products th {" +
            "  padding-top: 12px;" +
            "  padding-bottom: 12px;" +
            "  text-align: left;" +
            "  background-color: #a569bd;" +
            "  color: white;" +
            "}" +
            "</style>" +
            "" +
            "</head>" +
            "<body onload='mergeRows()'>" +
            "" +
            "<script>" +
            "function mergeRows() {" +
            "  const table = document.querySelector('table');" +
            "  let headerCell = null;" +
            "  for (let row of table.rows)" +
            "  {" +
            "    const firstCell = row.cells[0];" +
            "    if (headerCell === null || firstCell.innerText !== headerCell.innerText)" +
            "    {" +
            "      headerCell = firstCell;" +
            "    }" +
            "    else" +
            "    {" +
            "      headerCell.rowSpan++;" +
            "      firstCell.remove();" +
            "    }" +
            "  }" +
            "}" +
            "</script>" +
            "" +
            TTAG +
            "" +
            "</body>" +
            "</html>"

        Const tableHead = "<h1>Products by Suppliers</h1>"

        Const tableFmt =
            "<table id='products'>" +
            "  <thead>" +
            "    <th>Supplier</th>" +
            "    <th>Description</th>" +
            "    <th>Quantity Per Unit</th>" +
            "    <th>Unit Price</th>" +
            "  </thead>" +
            "{0}" +
            "</table>"

        Const dataRowFmt =
            "  <tr>" +
            "    <td>{0}</td>" +
            "    <td>{1}</td>" +
            "    <td>{2}</td>" +
            "    <td align='right'>{3:C}</td>" +
            "  </tr>"

        Using ds = New DataSet()
            ds.ReadXml(Path.Combine("Resources", "data", "GcNWind.xml"))

            Dim dtProds = ds.Tables("Products")
            Dim dtSupps = ds.Tables("Suppliers")

            Dim products =
            (From prod In dtProds.Select()
             Join supp In dtSupps.Select()
            On prod("SupplierID") Equals supp("SupplierID")
             Order By supp("CompanyName")
             Select New With {
                 .ProductName = prod("ProductName"),
                 .Supplier = supp("CompanyName"),
                 .QuantityPerUnit = prod("QuantityPerUnit"),
                 .UnitPrice = prod("UnitPrice")
            }).Take(16)

            Dim sb = New StringBuilder()
            sb.AppendLine(tableHead)
            For Each prod In products
                sb.AppendFormat(dataRowFmt, prod.Supplier, prod.ProductName, prod.QuantityPerUnit, prod.UnitPrice)
            Next

            Dim html = tableTpl.Replace(TTAG, String.Format(tableFmt, sb.ToString()))

            Dim tmp = Path.GetTempFileName()
            Using re = New GcHtmlRenderer(html)
                '' PdfSettings allow to provide options for HTML to PDF conversion:
                Dim pdfSettings = New PdfSettings() With {
                    .Margins = New Margins(0.2F, 1, 0.2F, 1),
                    .IgnoreCSSPageSize = True,
                    .DisplayHeaderFooter = True,
                    .HeaderTemplate = "<div style='color:#1a5276; font-size:12px; width:1000px; margin-left:0.2in; margin-right:0.2in'>" +
                        "<span style='float:left;'>Product Price List</span>" +
                        "<span style='float:right'>Page <span class='pageNumber'></span> of <span class='totalPages'></span></span>" +
                        "</div>",
                    .FooterTemplate = "<div style='color: #1a5276; font-size:12em; width:1000px; margin-left:0.2in; margin-right:0.2in;'>" +
                        "<span>(c) GrapeCity, Inc. All Rights Reserved.</span>" +
                        "<span style='float:right'>Generated on <span class='date'></span></span></div>"
                }
                '' Render the source Web page to the temporary file:
                re.RenderToPdf(tmp, pdfSettings)
            End Using
            '' Copy the created PDF from the temp file to target stream:
            Using ts = File.OpenRead(tmp)
                ts.CopyTo(stream)
            End Using
            '' Clean up:
            File.Delete(tmp)
        End Using
        '' Done.
    End Sub
End Class