Vista - Bind a datasourse to datagrid on MDIChild

I want to update MDIChild grid control by setting a datasource. How
does it possible from parent form?

In other words, I have a data grid control on a MDIChild form. I am
binding the data source from datagrid at the time of loading the MDI
Child.

Now, I need to refresh the data grid when there is a button click
happens on the parent form. I do not want to load the complete MDI
child again. I just want to update or refresh the data grid which is
on the MDI child.

Please let me know how can I do this.

I am able to call the data grid at the time of debugging like:

this.MdiChildren[0].Controls["ultraTabControl1"].Controls["tabVSR"].Controls["gridVSRt"]

How can I bind a data source to this? Is there any alternate way?
Please share your thoughts.

Thanks.