Question: I have a main form and a user control(with graphs). And I'm updating the graphs dynamically. 

```
 void foo(int i)
        {

            MainForm MF = (MainForm)MainForm.ActiveForm;
            if (tb != null)
            {
                tb.userGraph.updatesomething(i);
               // usergraph is the user control which has graphs
            }

        }

```

The problem is when I navigate out of the main form I cant update the graph. Is there any other way where I can write into the user control even if its not the active form?
If I create a new instance, the previous updates on the graph will be gone.

Answer: 
Use [InsertRange](http://msdn.microsoft.com/en-us/library/884ee1fz.aspx) method:

```
 List<T>.InsertRange(0, yourcollection);

```

Also look at [Insert](http://msdn.microsoft.com/en-us/library/sey5k5z4.aspx) method which you can add an element in your list with specific index.

> 
> Inserts an element into the List at the specified index.
> 
> 
> 

```
List<T>.Insert(0, T);

```
Please try `List<T>.InsertRange(0, IEnumerable<T>)`