Fix dynamism in questions with new VariableInputElement

UI/Input/VariableInputElement.ts

@@ -0,0 +1,35 @@
+import {InputElement} from "./InputElement";
+import {UIEventSource} from "../../Logic/UIEventSource";
+import BaseUIElement from "../BaseUIElement";
+import {VariableUiElement} from "../Base/VariableUIElement";
+
+export default class VariableInputElement<T> extends InputElement<T> {
+
+    private readonly value: UIEventSource<T>;
+    private readonly element: BaseUIElement
+    public readonly IsSelected: UIEventSource<boolean>;
+    private readonly upstream: UIEventSource<InputElement<T>>;
+
+    constructor(upstream: UIEventSource<InputElement<T>>) {
+
+        super()
+        this.upstream = upstream;
+        this.value = upstream.bind(v => v.GetValue())
+        this.element = new VariableUiElement(upstream)
+        this.IsSelected = upstream.bind(v => v.IsSelected)
+    }
+
+    GetValue(): UIEventSource<T> {
+        return this.value;
+    }
+
+    protected InnerConstructElement(): HTMLElement {
+        return this.element.ConstructElement();
+    }
+
+
+    IsValid(t: T): boolean {
+        return this.upstream.data.IsValid(t);
+    }
+
+}