I am "Object reference not set to an instance of an object."/SubForm/MainForm/busObje

[Andy Hopper]

I am getting the error "Object reference not set to an instance of an object." after launching a child form by a click of a button, reason why I know of is due to setting MdiParent to Null in order to launch this new form which leads to nulling out the reference of the busObject/main form, how can I restore the busObject/main form and avoid the error?

Here is some code:

1) Here where the new/child form is being launched:

            Form newForm = new QueryResearchGridControl();
            newForm.MdiParent = null;
            newForm.TopLevel = true;
            newForm.ShowDialog();
            newForm.MdiParent = this;

2) Here is some code from QueryResearchGr idControl():

  //This was a Control, now it is a form with a Control:
    public partial class QueryResearchGridControl : Form   
{
 
        public QueryResearchGridControl()
        {
            TopLevel = false;
            InitializeComponent();
 
        }
 
        private IResearchGridBusinessObject busObject;
        private BaseResearchGridForm myParent;
 
    public void Initialize(BaseResearchGridForm parent)   
    {
            myParent = parent;
            busObject = parent.BusinessObject;
    }

So as you probably notice that when MdiParent is being nulled out in item 1 above, it is causing the busObject to be null.

[Joseph Martell]

You could add a ParentChanged event handler to your child form. That way you avoid the null reference exception, but your code would still execute when the parent is eventually set.

[Andy Hopper]

I am re writing my reply in case previouse one did not post.

Hello Joseph,

Thank you for the feedback, I found out that mdiPrent has nothing to do with what I was doing so I removed it from my code, after further research I found out that I need to instantiate the busObject, allow me to explain, when the main form is launched (BaseResearchGr idForm), a button is clicked to launch another form that hosts a control (newForm/QueryResearchGr idControl), all is working well so far, but once I click the "Search" button on the new form (newForm/QueryResearchGr idControl) I get the error (null reference....) at the busObject assignments...e tc. I need to instantiate the busObject but I am new in c#/OO in general so I wonder if you can make some further recommendations . Thanks in advance.