dotnet/wpf · error · InvalidOperationException

throw new…

Error message

throw new InvalidOperationException(SR.Format(SR.MemberNotAllowedForView, "CancelEdit"));

What it means

CollectionViewProxy.CancelEdit() discards pending item changes by delegating to IEditableCollectionView.CancelEdit on the proxied view. When the wrapped view does not implement that interface (null `ecv` at CollectionViewProxy.cs:637), the proxy throws InvalidOperationException because this view does not support canceling edits.

Solutions

1. Check CanCancelEdit before calling CancelEdit
2. Back the view with a collection whose view implements IEditableCollectionView
3. Implement IEditableCollectionView on custom views that need edit transactions

Example fix

// before
proxy.CancelEdit();
// after
if (proxy.CanCancelEdit)
{
    proxy.CancelEdit();
}

if (!proxy.CanCancelEdit) return;
proxy.CancelEdit();

bool SupportsCancelEdit(CollectionViewProxy p) => p?.ProxiedView is IEditableCollectionView;

try { proxy.CancelEdit(); }
catch (InvalidOperationException ex) when (ex.Message.Contains("CancelEdit")) { /* unsupported view; discard changes manually */ }

When it happens

Trigger: Calling CancelEdit on a CollectionViewProxy whose ProxiedView is not IEditableCollectionView.

Common situations: Escaping row edits in a data-bound grid backed by an unsupported collection; view-models that always call CancelEdit in error handlers; switching collection implementations without updating view code.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• throw new…
• throw new…
• throw new…
• throw new…
• throw new…

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/e8ea941d08885afd. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/PresentationFramework/MS/Internal/Data/CollectionViewProxy.cs:637

            {
                throw new InvalidOperationException(SR.Format(SR.MemberNotAllowedForView, "CommitEdit"));
            }
        }

        /// <summary>
        /// Complete the transaction started by <seealso cref="IEditableCollectionView.EditItem"/>.
        /// The pending changes (if any) to the item are discarded.
        /// </summary>
        void IEditableCollectionView.CancelEdit()
        {
            IEditableCollectionView ecv = ProxiedView as IEditableCollectionView;
            if (ecv != null)
            {
                ecv.CancelEdit();
            }
            else
            {
                throw new InvalidOperationException(SR.Format(SR.MemberNotAllowedForView, "CancelEdit"));
            }
        }

        /// <summary>
        /// Returns true if the view supports the notion of "pending changes" on the
        /// current edit item.  This may vary, depending on the view and the particular
        /// item.  For example, a view might return true if the current edit item
        /// implements <seealso cref="IEditableObject"/>, or if the view has special
        /// knowledge about the item that it can use to support rollback of pending
        /// changes.
        /// </summary>
        bool IEditableCollectionView.CanCancelEdit
        {
            get
            {
                IEditableCollectionView ecv = ProxiedView as IEditableCollectionView;
                if (ecv != null)
                {

View on GitHub (pinned to 81131a70a4)