Цикл всех bindingsources и всех наборов данных во всех открытых формах mdichildren

My project is c# WinForms. I have 2 forms in my project, one of them is a MdiParent form and I want to through its MdiChildren forms and if they have a BindingSource I want to make it endedit. And if they have a dataset I want to test it if haschanges or not. Thanks in advance for help.

I tried this code

foreach (Form frmm in Application.OpenForms)
        {
                foreach( Control c in frmm.Controls)
                {
                    if (c is BindingSource)
                    {
                        c.endedit();
                    }
                }

        }

foreach (Form frmm in Application.OpenForms)
        {
            foreach (Control c in frmm.Controls)
            {
                if (c is dataset)
                {
                    if (c.HasChanges())
                    {
                        MessageBox.Show("there are a unsaved data")
                    }
                }
            }
        }