We're using the C# version of MPXJ, but rather than examining an existing Project file we're using it to produce a new file purely from code (extracting data from a third party system) for import to Project via MSPDIWriter.
The goal is to have Tasks that report as completed in the other system show up with 100% completion and the ✔ checkmark next to them on the Gantt view when the XML is loaded in Project. This is working as expected only when the total Duration assigned to a task is zero days; for any other duration when Project opens the Task's percentage complete is set to 0%.
Our devs aren't Project people, so it's not clear to us which properties will affect this behaviour:
Task childTask = parent.AddTask();
childTask.Name = sourceItem.Title;
Duration duration = Duration.getInstance(sourceItem.Days, TimeUnit.DAYS);
childTask.PercentageComplete = new java.lang.Integer(childItem.PercentageComplete);
childTask.PercentageWorkComplete = childTask.PercentageComplete;
ResourceAssignment assignment = childTask.AddResourceAssignment(resource);
assignment.Work = duration;
assignment.RemainingWork = duration;
assignment.percentageWorkComplete = childTask.PercentageComplete;
childTask.EffortDriven = false;
childTask.Priority = childItem.Priority;
childTask.Duration = duration;
childTask.BaselineDuration = duration;
if (childItem.PercentComplete == 100)
{
childTask.RemainingWork = Duration.getInstance(0, TimeUnit.DAYS);
}
This sample code works through the steps to create a file from scratch with various combinations of un-started, partially complete, and completed tasks both with and without resource assignments. There is a C# version but I must admit that I haven't kept the two in line. The Java version is probably the more complete, hopefully it should be fairly straightforward to get a working C# version.
I'd suggest starting with these samples and generate MSPDI files from them first, verifying that you get the expected result when the files are imported into MS Project. Hopefully you'll then be able to update your code based on the approach taken in the sample files.
One thing to watch for is that there were some improvements made recently to MSPDI generation relating to getting percent complete to appear correctly so it would be worth verifying that you are working with the most recent version of MPXJ (7.9.2 at the time of writing).