Fix Blazor TextArea Not Updating#67088
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NanthiniMahalingam wants to merge 6 commits into
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Description
When a <textarea> is initialized with content placed between its opening and closing tags (as per the HTML spec), and an onchange handler is wired up for two-way binding, the textarea's displayed value does not update when the component re-renders with new data — even though a sibling using a value attribute updates correctly.
Root cause
When Blazor's interactive renderer (WebAssembly/Server) processes an updateText diff edit for a <textarea>'s child text node, it only sets textNode.textContent. Browsers decouple the value property (the displayed/user-editable content) from textContent/defaultValue once the user has edited the field. So subsequent Blazor re-renders only update the defaultValue, leaving the visible value stale.
Code changes
After updating textNode.textContent, check if the text node's DOM parent is an HTMLTextAreaElement. If so, sync textarea.value = textarea.textContent in BrowserRenderer.cs
Testing
Added the Unit test for the text area not updating case. After adding the fix, text area value is updated when current page parameter changes.
Fixes #45951
Output
Before changes
Beforefix.mp4
After Changes
Afterfix.mp4