Use Office File API on Linux

• Jan 20, 2023
• 4 minutes to read

This tutorial describes how to create a simple Office File API application for .NET on Linux.

Prerequisites

• .NET Core 3.1 / .NET 5.0 SDK / .NET 6.0 SDK or later

• A code editor. This tutorial uses Visual Studio Code.

• Libgdiplus library. This library is required to use System.Drawing in Office File API applications.

  Add the Mono repository to your system to install the latest libgdiplus version or use the corresponding terminal commands below (depending on your Linux distribution):

  Ubuntu

  sudo apt install -y libgdiplus libc6 libc6-dev
  

  Debian

  sudo apt install -y libgdiplus libc6 libc6-dev
  

  CentOS / RHEL / Fedora

  sudo yum install -y libgdiplus glibc glibc-devel
  

  openSUSE

  sudo zypper install -y glibc glibc-devel libgdiplus0
  

  Alpine

  apk add icu-libs libgdiplus
  

• Install the font libraries below (based on your Linux distribution) to measure, render, and export document text to PDF within your Office File API application:

  Ubuntu

  sudo apt install -y fontconfig libharfbuzz0b libfreetype6
  

  Debian

  sudo apt install -y fontconfig libharfbuzz0b libfreetype6
  

  CentOS / RHEL / Fedora

  sudo yum install -y libicu fontconfig harfbuzz freetype
  

  openSUSE

  sudo zypper install -y libicu fontconfig libharfbuzz0 freetype
  

  Alpine

  apk add icu-libs icu-dev harfbuzz freetype fontconfig libc6-compat libc-dev
  

  Tip

  You can also install the ttf-mscorefonts-installer package to add Microsoft TrueType core fonts (Arial, Times New Roman, Courier New, and so on) to your system. Run the following terminal command to install this package in Debian / Ubuntu and accept the license agreement:

  sudo apt-get install ttf-mscorefonts-installer

• Optional. If your application needs to render JPEG images within PDF files, install the packages below based on your Linux distribution (or any other packages that implement the libjpeg API v6.2 or v8.0):

  Ubuntu

  sudo apt install -y libjpeg-turbo8
  

  Debian

  sudo apt install -y libjpeg62-turbo
  

  CentOS / RHEL / Fedora

  sudo yum install -y libjpeg-turbo
  

  openSUSE

  sudo zypper install -y libjpeg8
  

  Alpine

  apk add libjpeg-turbo
  

Create an Application

1. Create a folder for you project (OfficeConsoleApp in this example) and open this folder in Visual Studio Code.

2. Click View → Terminal in the main menu to open the integrated terminal.

3. Use the dotnet new command to create a new console application.

   Create a C# project

   dotnet new console
   

   Create a VB project

   dotnet new console -lang VB
   

   This command adds the following files to your folder:

   • OfficeConsoleApp.csproj / OfficeConsoleApp.vbproj

   • Program.cs / Program.vb.

4. Obtain your NuGet Feed URL and install the DevExpress.Document.Processor NuGet package as described in the following topic: Use NuGet Packages to Install Office File API Components.

   Important

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

   You should also install the DevExpress.Pdf.SkiaRenderer package to enable rendering of PDF page content within your app.

5. Paste the code below in the Main method of the Program.cs file (or the Program.vb file’s Main procedure for Visual Basic). The following example converts a DOCX file to PDF:

   C#

   using DevExpress.XtraRichEdit;
   // ...
   
   static void Main(string[] args) {
       using (var wordProcessor =
           new RichEditDocumentServer()) {
           // Load a document from a file.
           wordProcessor.LoadDocument("Document.docx", DocumentFormat.OpenXml);
           // Export the document to PDF.
           wordProcessor.ExportToPdf("PdfDocument.pdf");
       }
   }
   

   VB.NET

   Imports DevExpress.XtraRichEdit
   ' ...
   
   Sub Main(args As String())
       Using wordProcessor As RichEditDocumentServer = New RichEditDocumentServer()
           ' Load a document from a file.
           wordProcessor.LoadDocument("Document.docx", DocumentFormat.OpenXml)
           ' Export the document to PDF.
           wordProcessor.ExportToPdf("PdfDocument.pdf")
       End Using
   End Sub
   

Run the Application

Type dotnet run in the terminal window to run the program.

dotnet run

The following image illustrates the result:

Troubleshooting

System.Drawing.Common is Supported on Windows Only

With the .NET 6 release, the System.Drawing.Common library is compatible with Windows only. Applications that are built for non-Windows platforms now throw the TypeInitializationException and PlatformNotSupportedException exceptions. Refer to the following breaking change for more information: System.Drawing.Common only supported on Windows.

You can set the System.Drawing.EnableUnixSupport runtime configuration switch to true in the runtimeconfig.json file to enable support for non-Windows operating systems and to avoid runtime exceptions:

JSON

{
   "configProperties": {
      "System.Drawing.EnableUnixSupport": true
   }
}

However, this runtime configuration switch will not be supported in .NET 7 and higher, and all apps that use Sytem.Drawing.Common on non-Windows platforms will throw PlatformNotSupportedException. To address this issue, we plan to implement our own cross-platform rendering engine based on the SkiaSharp library. See the following blog post for details: DevExpress Cross-Platform Products – Getting Ready for .NET 7.