Setting field from another variable/thymeleaf

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ThymeLeaf

Hello,
I am trying to set a th:field with a value from another model but I keep getting null.

<input
 th:id="*{roomType[__${rowStat.index}__].type}"
th:name="*{roomType[__${rowStat.index}__].type}"
th:value="${viewModel.getRooms()[__${rowStat.index}__].getType()}"
 type="text"
hidden="hidden"/>

What I have tried:

I found out that th:field overrides th:value and that Thymeleaf th:field generates 3 html attributes id , name an value so instead of th:field , I should use th:id , th:name and th:value. But why do I get null?