Save a value and verify later

Hi,

I want to do this steps:
Navigate on a silverlight webapplication site. Click Search Button.
I get one result.
On the resultview I can see a textblock. Now I want to save the data from this textblock in a variable.
Do some other background steps.
Go again on the webapplication, search, get one result.
Now I want to verify, that the text is not the same as before.

My question is, how can I save the value from the textblock in a variable and verify it later?

As I recorded the test, I can access the Textblock, but did not find a way to save the value from the text with the Telerik GUI elements.
So I think I need to access it via code and save it in this step, where I can see it, right?
But how can I access the textblock from the code to do so?

There is one button "Add to project elements" to put the element in the elementsTree. I tried this one, and then tried to access in the next code step via
string sjobid = Pages.VPMSMediaCenter.SilverlightApp0.sjobidTextblock.Text;


But as I play the test, I got the error message:

Exception thrown executing coded step: '[AF001_QA001_Umbenennung_CodedStep1] : Save SJobID in variable'.
InnerException:
System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.ThrowHelper.ThrowArgumentOutOfRangeException()
   at ArtOfTest.WebAii.Silverlight.SilverlightAppsList.get_Item(Int32 index)

I am new to Telerik Teststudio, maybe there is a explanation (didn't find it in forum/documentation) somewhere?
Or someone can help me here?

Best regards,
Adriane