Editing/Writing mpp file on c# using mpxj

Question

I'm trying to view and edit Tasks on a mpp file using mpxj on c#. I wrote some lines and tring to write a file that is already complete adding a new Task.

But when the code arrives to the write part, it create the file in the path I meant but the file is empty and if I try to read that file it give me the System.NullReferenceException : Object reference not set to an instance of an object error. It's the first time code with this mpxj library.

 ProjectReader reader = new MPPReader();
 ProjectWriter writer = new MPXWriter();
 private ProjectFile project;

 public ProjectFile OpenReaderProject()
    {
        string filePath = "Files/Prova file1.mpp";

        try
        {
            project = reader.read(filePath);
        }
        catch (MPXJException ex)
        {
            Console.WriteLine("Errore durante l'apertura del file .mpp: " + ex.Message);
        }
        return project;
    }

    public ProjectFile OpenWriterProject()
    {
        string filePath = "Files/Prova file1.mpp";

        try
            {
            writer.write(project, filePath);
            }
            catch (MPXJException ex)
            {
                Console.WriteLine("Errore durante la scrittura del file .mpp: " + ex.Message);
            }
        return project;
    }

This is the write and reading part.

 public void AddTask()
    {
        var project = OpenReaderProject();

        var task = project.addTask();
        task.setName(java.lang.String.valueOf("Attività di esempio"));
        var taskDto = _mapper.Map<TaskDto>(task);
            OpenWriterProject();

    }`

This is the add task function and calling the OpenWriterProject. What's wrong with it? Feel free to answer me ;) Thanks

score 1 · Answer 1 · answered Jul 03 '23 at 15:52

You will have to close the reader before using the writer. I suggest that you only create the reader and writer objects just before you use them, like this:

ProjectFile project;
string filePath = "Files/Prova file1.mpp";

public ProjectFile OpenReaderProject()
{
    ProjectReader reader = new MPPReader();
    project = reader.read(filePath);
    return project;
}

public ProjectFile OpenWriterProject()
{
    ProjectWriter writer = new MPXWriter();
    writer.write(project, filePath);
    return project;
}

Editing/Writing mpp file on c# using mpxj

1 Answers1