Workbook.LoadDocumentAsync(String, CancellationToken) Method

SECURITY NOTE

Downloading documents passed into the LoadDocument method may create security issues. Review the following help topic and learn how to spot, analyze, and prohibit unwanted download requests:

Suppress Control Requests to Download Data from External URLs

Loads a document asynchronously from a file.

You need a license for the DevExpress Office File API Subscription or DevExpress Universal Subscription to use this method in production code.

Namespace: DevExpress.Spreadsheet

Assembly: DevExpress.Docs.v23.2.dll

NuGet Package: DevExpress.Document.Processor

Declaration

C#

public Task<bool> LoadDocumentAsync(
    string fileName,
    CancellationToken cancellationToken
)

VB.NET

Public Function LoadDocumentAsync(
    fileName As String,
    cancellationToken As CancellationToken
) As Task(Of Boolean)

Parameters

Name	Type	Description
fileName	String	A string that specifies a file to load (including the full path).
cancellationToken	CancellationToken	A CancellationToken object used to trace the requests to cancel an operation.

Returns

Type	Description
Task<Boolean>	A Task<TResult> object that return true if the document was loaded successfully; otherwise, false.

Remarks

The Spreadsheet uses the built-in IFormatDetectorService service implementation to detect the format of the loaded document.

If the format detection fails, the Workbook.InvalidFormatException event fires.

Handle the Workbook.DocumentLoaded event to determine when you can safely modify the loaded document.

The following example shows how to asynchronously convert an XLSX file to PDF format:

C#

private async void ConvertXlsx2PdfWithCancellation()
{
  using (CancellationTokenSource source = new CancellationTokenSource(10000))
  {
    using (Workbook workbook = new Workbook())
      {
          try
          {
              await workbook.LoadDocumentAsync("Document.xlsx", source.Token);
              await workbook.ExportToPdfAsync("Result.pdf", source.Token);
          }
          catch (OperationCanceledException)
          {
              // Your code to handle cancellation.
          }
      }
  }
}

VB.NET

Private Async Sub ConvertXlsx2PdfWithCancellation()
    Using source As CancellationTokenSource = New CancellationTokenSource(10000)

        Using workbook As Workbook = New Workbook()

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

Calculate Formulas in the Loaded Document

The default calculation mode for a Workbook is Manual. This mode implies that the Spreadsheet does not recalculate formulas when you load a document. Call the Workbook.Calculate or Workbook.CalculateFull method to recalculate all formulas in the workbook.

C#

using (Workbook workbook = new Workbook())
{
    // Load a document.
    // ...
    // Calculate formulas in the document.
    workbook.Calculate();
    // ...
}

VB.NET

Using workbook As New Workbook()
    ' Load a document.
  ' ...
    ' Calculate formulas in the document.
    workbook.Calculate()
    ' ...
End Using

Change Calculation Mode

Use the Workbook.Options.CalculationMode property to change the calculation mode for a Workbook.

The following calculation modes are available:

• Manual (default) - Formulas are calculated only on demand (after the Calculate method call). It allows you to improve document generation speed for large workbooks with multiple formulas.

• UseDocumentSettings - Uses the calculation mode specified in the loaded document (this value is stored in the Workbook.DocumentSettings.Calculation.Mode property).

• Automatic - Recalculates formulas each time a cell value, formula, or defined name changes.

C#

using (Workbook workbook = new Workbook())
{
    // Change the calculation mode.
    workbook.Options.CalculationMode = WorkbookCalculationMode.UseDocumentSettings;
    // ...
    // Load a document.
    // ...
}

VB.NET

Using workbook As New Workbook()
  ' Change the calculation mode.
  workbook.Options.CalculationMode = WorkbookCalculationMode.UseDocumentSettings
  ' ...
  ' Load a document.
  ' ...
End Using