dotnet/wpf · error · System.InvalidOperationException

SR.ValueReadonly

Error message

SR.ValueReadonly

What it means

InvalidOperationException(SR.ValueReadonly) is thrown by the internal static SetValue when the ListView does not have label editing enabled (ListViewEditable false). The ValuePattern edit is implemented by launching in-place label editing, so a non-editable list means its values are read-only.

Solutions

  1. Set ListView.LabelEdit = true on the target control to enable label editing.
  2. Use BeginEdit/label-edit UI interaction instead of ValuePattern on non-editable lists.
  3. Catch InvalidOperationException and treat the value as read-only.
  4. Verify IsReadOnlyProperty on the ValuePattern before calling SetValue.

Example fix

// before
listView1.Items[0].Text = "x"; // via UIA SetValue -> fails when LabelEdit is false
// after
listView1.LabelEdit = true; // enables LVS_EDITLABELS so UIA SetValue works
Defensive patterns

Strategy: validation

Validate before calling

var readOnly = (bool)item.CurrentPropertyValue(ValuePattern.IsReadOnlyProperty);
if (readOnly) throw new InvalidOperationException("value is read-only (LabelEdit disabled)");

Try / catch

try { valuePattern.SetValue(text); }
catch (InvalidOperationException) { /* read-only: use app API or enable LabelEdit */ }

Prevention

When it happens

Trigger: Calling SetValue (ValuePattern) on a ListView item whose control lacks LVS_EDITLABELS (ListViewEditable returns false).

Common situations: Default WinForms ListView (LabelEdit=false) automated with a SetValue call; test scripts assuming all list items are editable; app changed LabelEdit at runtime or across versions.

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

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/d9c046ae1519ec71. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/UIAutomation/UIAutomationClientSideProviders/MS/Internal/AutomationProxies/WindowsListViewItem.cs:751

                mask = NativeMethods.LVIF_GROUPID,
                iItem = lvItem
            };

            if (XSendMessage.GetItem(hwnd, ref item))
            {
                return item.iGroupID;
            }

            return -1;
        }

        internal static void SetValue (string val, IntPtr hwnd, int item)
        {
            ArgumentNullException.ThrowIfNull(val);

            if (!WindowsListView.ListViewEditable (hwnd))
            {
                throw new InvalidOperationException(SR.ValueReadonly);
            }

            Misc.SetFocus(hwnd);

            // set focus to the item
            WindowsListView.SetItemFocused (hwnd, item);

            // retrieve edit window
            IntPtr hwndEdit = WindowsListView.ListViewEditLabel (hwnd, item);

            if (IntPtr.Zero == hwndEdit)
            {
                throw new InvalidOperationException(SR.OperationCannotBePerformed);
            }

            // re-use editbox proxy to do the job
            // Note: we will pass null and -1 for some of the parameters
            // this is ok, since the only thing that matters to us is an ability to set the text

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