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Getting Started with .Net

For many people the easiest way to work with MPXJ is via NuGet. The .Net assemblies and their dependencies can also be found in the zip file distribution from GitHub or SourceForge.

You'll find a general introduction to MPXJ's functionality here.

MPXJ assemblies

MPXJ ships with a set of .Net Framework and .Net Core assemblies, which are managed for you by NuGet or can be found in the src.net\lib\net45 and src.net\lib\netcoreapp3.1 folders of the distribution respectively.

There are actually three different .Net DLLs shipped with MPXJ - you only need one of these:

  • mpxj.dll - this is the default .Net version, the API is identical to the Java version
  • mpxj-for-csharp.dll - in this version the API has been modified to make it less like Java and more like C#: there are properties rather than getter and setter methods and the method names follow the same uppercase initial letter convention used by C#.
  • mpxj-for-vb.dll - this version also transforms getters and setters into properties, but the method names are unchanged. VB is case insensitive and can't cope with the seeing two methods whose name differs only by case

As noted above, in the "for C#" and "for VB" versions of the MPXJ DLL, getters and setters have been replaced by properties. For example, where you would have previously written code like this:

String text = task.getText();
task.setText(text);

Now when you work with the "for C#" and "for VB" versions of the MPXJ DLL, you'll be able to write code in a more familiar style:

String text = task.Text
task.Text = text;

Also noted above, in the case of the "for C#" MPXJ DLL, method names have been modified to begin with an initial capital, so the code will again have a more familiar style. For example, using the original Java method names you'd write something like this:

Task task = projectFile.addTask();

Using the "for C#" DLL your code will look like this:

Task task = projectFile.AddTask();

MPXJ dependencies

Once you have selected the version of the MPXJ DLL most suitable for your project, you will need to add its dependencies. If you are using NuGet to manage your dependencies, this is done for you automatically. If you are managing the dependencies manually, the files you need will all be in the relevant sub folder with the src.net\lib folder of the MPXJ distribution.

.Net samples

MPXJ ships with some sample files which can be found in the src.net\samples folder of the distribution. These files illustrate how the MPXJ API can be used to manipulate project data. In particular the MpxjQuery example shows how various elements which make up the project data can be queried. Two versions of this utility are present in src.net\samples, one written in C#, and the other written in Visual Basic (VB) to illustrate the basics of using MPXJ in either language. Even if you are developing software in a .Net language you may still find it useful to refer to the Java examples, and indeed the original Java source of MPXJ, to give you an insight into how the API can be used.

.Net and Java types

The .Net version of MPXJ has been generated directly from the Java version using a tool called IKVM. One of the side effects of using IKVM to perform this conversion is that the MPXJ exposes .Net versions of the original Java data types, so for example you will find that the API returns a type called Date rather than a .Net DateTime, and collections which don't expose the familiar IEnumerable interface.

To simplify the translation between Java and .Net types, a set of extension methods have been provided. These are included n the NuGet package, and the source can be found in the src.net\utilities folder, in a project called MpxjUtilities. This project contains extension methods which enhance both Java and .Net classes to make it easier to pass data to and from the API. For example the extension method ToIEnumerable is added to Java collection data types which allows them to be iterated using the familiar foreach .Net syntax.

To use these extension methods, simply add a reference to the MpxjUtilities assembly in your own project. The methods themselves are documented in the source, and examples of their use can be seen in the samples provided in the src.net\samples folder.

MPXJ and the GAC

For your convenience two batch files are provided in the src.net\lib\net45 directory: mpxj-gac-install.bat and mpxj-gac-uninstall.bat. These batch files install the MPXJ assemblies into the GAC and uninstall the MPXJ assemblies from the GAC using the gacutil global assembly cache tool. Note that these batch files assume that gacutil is available on the path.