If

If

Signature

<If Test="{State.Error}">
  <Text Value="加载失败" Color="Destructive" />
</If>

Attributes

Truthiness rules

Example

<If Test="{Data.News}">
  <Text Value="{Data.News.Title}" />
</If>

<If Test="{State.Loading}">
  <Text Value="加载中…" Color="Muted" />
</If>

<If Test="{State.Error}">
  <Text Value="加载失败" Color="Destructive" />
</If>

Runtime behavior

• When the condition is false the subtree does not render at all, but Data inside it is still prefetched (it was collected at parse time).
• There is no Else; for an either/or case use two opposite conditions, or return the state from a script.
• Test accepts {...} or a bare path.

Gotchas

• An empty array counts as false; to detect “the array exists but is empty”, check its length or use a script result.
• Do not put Resources / Triggers / Function inside If; they are only allowed at the root.