MVP how to correctly return a variable in the ViewModel of the progressbar?

Question

.NET

Separated form from logic, according to the MVP principle. I want to return a value from the logic to the progressbar.
I press the first time - it does not work.
The second time - it does not work to the end (the thread dies?)
I thought to initialize the variable separately (temp), so as not to access the i memory area, it did not help.
I do 10ms - it works (but I'm not sure what is right)
What am I doing wrong?
Method in Presenter

public void Start()
{
model.Cicle();
SetValProg();
}
public void SetValProg()
{
form.UpdateView(model.progressVal);
}

Method in view

public void UpdateView(int progressBarVal)
{
progressBar1.Value = progressBarVal;
}

Answer 1

Here
and smoke aside:
- InvokeRequired
- SynchronizationContext
This is a matter of accessing controls from a third-party thread.

Answer 2

Look at the code that regularly reads progressVal from the model and shoves it into the progress bar. In other words, is SetValProg called from where else, except at startup? Personally, I don't see any of the threading issues that tex0 is talking about yet , because from another thread, only the int field of the Model is set.