I find answer for this question from internet and also here. Some got some help from here. But it doesn't worked 100% fo my situation. So let me describe all things detailed. This is about three forms. To our easy understand I'll named those Form1,Form2,Form3. Only Form1 is MDI parent. Other two forms are child forms.
When user select button on the Form1(parent) it loads Form2(child).
after if user select combobox zero(0th) item it loads Form3 (child). At that time all three forms opened.
Form2 load by this code : (by button click which on MDI parent form)

 Dim foorm2 As New Form2
 foorm2.MdiParent = Me

Form3 load by this code : (by select combobox's 0th item which on form2)

Dim foorm3 As New Form3
foorm3.MdiParent = Form1

(above code part is inside if-else-end loop. So i'm not going to put all)
Then all three forms loads. Child forms load inside Form1. Then we'll move to next part.
There are many textboxes in the form3. But to our easy understand we'll think it has one textbox. And other thing is in Form2 there are many textboxes.
My need is this. When I click on save button on the Form3. These textbox values should be saved to database (saving database code is okay) and close Form3. In that time I want to get Form3 textbox values instance to the Form2.
How should I do this? please advice with code examples . I appreciate it :)

Instead of firing off another question, the least you could do is answer the posts in your previous questions. Just saying that they don't work doesn't tell anyone how to fix it. In fact an answer in one of those posts, does exactly what you describe.

This question has already been answered. Start a new discussion instead.