How to: Export a Document to HTML

• Jan 20, 2021
• 3 minutes to read

Important

The Workbook class is defined in the DevExpress.Docs.v20.2.dll assembly. Add this assembly to your project to use the Workbook API. You need a license for the DevExpress Office File API Subscription or DevExpress Universal Subscription to use this assembly in production code.

The example below demonstrates how to save a worksheet as HTML file using the Workbook.ExportToHtml method. To specify export options, create an instance of the HtmlDocumentExporterOptions class and pass it as a parameter to the ExportToHtml method.

View Example

ExportActions.cs

Worksheet worksheet = workbook.Worksheets["Grouping"];
workbook.Worksheets.ActiveWorksheet = worksheet;

HtmlDocumentExporterOptions options = new HtmlDocumentExporterOptions();

// Specify the part of the document to be exported to HTML.
options.SheetIndex = worksheet.Index;
options.Range = "B2:G7";

// Export the active worksheet to a stream as HTML with the specified options.
using (FileStream htmlStream = new FileStream("OutputWorksheet.html", FileMode.Create))
{
    workbook.ExportToHtml(htmlStream, options);
}

System.Diagnostics.Process.Start("OutputWorksheet.html");

ExportActions.vb

Dim worksheet As Worksheet = workbook.Worksheets("Grouping")
workbook.Worksheets.ActiveWorksheet = worksheet

Dim options As New HtmlDocumentExporterOptions()

' Specify the part of the document to be exported to HTML.
options.SheetIndex = worksheet.Index
options.Range = "B2:G7"

' Export the active worksheet to a stream as HTML with the specified options.
Using htmlStream As New FileStream("OutputWorksheet.html", FileMode.Create)
    workbook.ExportToHtml(htmlStream, options)
End Using

System.Diagnostics.Process.Start("OutputWorksheet.html")

Asynchronous Export

Use the Workbook.ExportToHtmlAsync method to asynchronously export a workbook to HTML format.

Important

Take into account the following when you call this method:

• The events fired by this method’s call may occur in a different thread than the target operation.

• The operation is not thread safe (documents should not be accessed simultaneously by different threads). Wait until the operation is completed before working with the document, i.e., use the await operator.

The code sample below asynchronously exports the first worksheet of the loaded XLSX document to HTML using the CancellationToken object:

C#

private async void ConvertXlsx2HtmlWithCancellation()
{
  using (CancellationTokenSource source = new CancellationTokenSource(10000))
  {
    using (Workbook workbook = new Workbook())
      {
          try
          {
              await workbook.LoadDocumentAsync("Document.xlsx", source.Token);
              await workbook.ExportToHtmlAsync("Result.html", 0, source.Token);
          }
          catch (OperationCanceledException)
          {
              // Your code to handle cancellation.
          }
      }
  }
}

VB.NET

Private Async Sub ConvertXlsx2HtmlWithCancellation()
    Using source As CancellationTokenSource = New CancellationTokenSource(10000)

        Using workbook As Workbook = New Workbook()

            Try
                Await workbook.LoadDocumentAsync("Document.xlsx", source.Token)
                Await workbook.ExportToHtmlAsync("Result.html", 0, source.Token)
            Catch __unusedOperationCanceledException1__ As OperationCanceledException
            ' Your code to handle cancellation.
            End Try
        End Using
    End Using
End Sub

Calculate Formulas Before Export

The default calculation mode for a Workbook is Manual. This mode implies that the Spreadsheet component does not recalculate formulas before it generates an HTML file. Call the Workbook.Calculate or Workbook.CalculateFull method to calculate all formulas in the workbook before you export it to HTML.

C#

using (Workbook workbook = new Workbook())
{
    // Load a document.
    // ...
    // Modify the document.
    // ...
    // Calculate formulas in the document.
    workbook.Calculate();
    // Export the first worksheet to HTML.
    workbook.ExportToHtml("Result.html", 0);
}

VB.NET

Using workbook As New Workbook()
    ' Load a document.
    ' ...
    ' Modify the document.
    ' ...
    ' Calculate formulas in the document.
    workbook.Calculate()
    ' Export the first worksheet to HTML.
    workbook.ExportToHtml("Result.html", 0)
End Using