Task export on MSProject with error on blank/empty tasks

Question

I created an Addin in C# VSTO to export tasks from MSProject to a SQLServer. My code works fine until the tasks in MSProject have an empty/blank entry.

 

I have no idea for a workaround. It seems, that die foreach isn't working here.

MsProject.Tasks tasks = Globals.ThisAddIn.Application.ActiveProject.Tasks;
using (SqlConnection cnn = new SqlConnection(connectionString))
{
try
{
// Open the connection to the database.
cnn.Open();
foreach (Microsoft.Office.Interop.MSProject.Task t in tasks)
{
DateTime start = (DateTime)t.Start;
DateTime finish = (DateTime)t.Finish;
using (SqlCommand cmd = new SqlCommand(sql, cnn))
{
// Create and set the parameters values
cmd.Parameters.Add("@id", SqlDbType.Int).Value = t.ID;
cmd.Parameters.Add("@name", SqlDbType.NVarChar).Value = t.Name;
cmd.Parameters.Add("@start", SqlDbType.DateTime).Value = start;
cmd.Parameters.Add("@finish", SqlDbType.DateTime).Value = finish;
int rowsAdded = cmd.ExecuteNonQuery();
}
}
MessageBox.Show("Data transfered" );
}

In MSProject it looks like:

 

 

Does anyone have an idea how to loop over or include the blank/empty tasks?

 

Currently i only get NullPointerReference of the object as Error and the Third task won't be export to SQL Server.