Jump to entry in DropDownBox

Hi Friends,

I have a table and a Dialog with dropdownbox.

Now I want to mark an table entry and when open the Dialog.

And now the Dropdownbox should be set to the entry I have selected  in table.

I tried with set selectedItemId and set selectedKey but it allways Shows me the first entry in the dropdown.

Is where a way to move to a certain value in the Dropdown?

Thanks and Rg. Joerg