problem with 2Forms+progressbar+background worker

[bbonik]

Dear all,
I am having a very frustrating problem with a project in Visual Studio 2008 C#. I have tried everything, I have searched everywhere, but it seems that nothing works. I would appreciate if someone gave me some directions or suggestions, as to where to look for the solution.
What I want to do:
I have 2 forms. The MAIN form, runs a heavy image processing algorithm, using a background worker. The second form, FORM2 must have a progress bar, which will display the progress of the image processing executed in MAIN form. It must also have a CANCEL button, which will allow the canceling of the image processing algorithm.

What I have done so far:
1. I have managed to solve the problem using only one form: there is no FORM2. The progress bar and the cancel button are on the MAIN form. Everything works fine. But this is not the thing I have to do! I really need the cancel button and the progress bar on a different form.
2. I have managed to show the progress bar on FORM2 running smoothly, but I cannot interact with FORM2 (the mouse pointer becomes a hourglass when I hover it over FORM2, thus, I cannot press the CANCEL or the X button).
In order to do that, I wrote the following code:

In MAIN form:


FORM2 PR = new FORM2();
PR.Show();

for (i = 0; i < imsize_y; i++)
{
//calculate the progress degree and store it in ‘Process’ variable

PR.progressBar1.Value = Process;
PR.Refresh(); //otherwise the PR form is not redrawn


if (backgroundWorker1.CancellationPending
{
PR.Close();//where the code stops in case cancel is pressed
break;
}


for (j = 0; j < imsize_x; j++)
{
//heavy image processing

}
}

PR.Close();




3. I have also tried to use PR.ShowDialog() instead of PR.Show(),in order have focus on FORM2. However, in this case, the image processing stops until and I have to press something in FORM2 in order to proceed with the image processing in MAIN form.

I know that this has to do something with threading, but I don’t know what. When the MAIN form runs, I cannot interact with FORM2. I have found examples where I can communicate variables between forms, but, in these examples, there is no background worker involved.

I would appreciate any suggestions or directions, as to where to look for this solution.

[mavy-online]

So if you can access objects on form1 from form 2, all is okay ?

The backgroundworker modifier must be PUBLIC. , i think its private by default.

When you create form2 , you must pass the main form as an argument, to the constructor of form 2.

That goes like this:

newform Form2 = new Form2(this);

notice the THIS, which refers to the current form your working on.
Now, you need to take the code of form2, and look for the constructor, and add a parameter:

public Form1(Form1 parent)

Now, you passed, a reference to the main form, to the constructor of form2, which you can access in Form2 using: parent
EX: parent.backgroundworker

To access the parent (the main form) from anywhere in form2, make it globally available
by creating another object of Form1 type, in a global scope, and assigning the passed object, to it.

    public partial class Form1 : Form
    {

       private Form1 parent;

        public Form1(Form1 parent)
        {
            InitializeComponent();
            this.parent = parent;
        }
    }
}

I hope, i explained this correctly.

[mavy-online]

2. I have managed to show the progress bar on FORM2 running smoothly, but I cannot interact with FORM2 (the mouse pointer becomes a hourglass when I hover it over FORM2, thus, I cannot press the CANCEL or the X button).

Isnt that because your progress bar is running on form2 ?

If so, put the progress bar on another thread/background worker, and that problem should be solved.

[BigEd781]

There is no need to make things public like that mavy. Just use events to communicate between forms.