protected virtual IList <IFieldDefinition> MergeTelemetryFields(IList <IFieldDefinition> importedFieldDefinitions) { var updated = new List <IFieldDefinition>(); var removed = new List <IFieldDefinition>(); var current = FieldDefinitions.ToList(); var promptMergeAll = false; var mergeAll = false; foreach (IFieldDefinition importedFieldDefinition in importedFieldDefinitions) { var existing = current.FirstOrDefault(f => f.Name == importedFieldDefinition.Name); if (existing != null) { if ((!promptMergeAll && !mergeAll) || (promptMergeAll && !mergeAll)) { var dialogResult = MessageBox.Show(this, $"Telemetry field definition list already contains an entry for '{importedFieldDefinition.Name}'. Overwrite?", "Duplicate Telemetry Entry", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Warning); if (dialogResult == DialogResult.Yes) { removed.Add(existing); updated.Add(importedFieldDefinition); if (!promptMergeAll) { var mergeAllDialogResult = MessageBox.Show(this, "Overwrite all Telemetry duplicates?", "Duplicate Telemetry Entry", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question); if (mergeAllDialogResult == DialogResult.Cancel) { return(FieldDefinitions); } else { mergeAll = (mergeAllDialogResult == DialogResult.Yes); promptMergeAll = true; } } } else if (dialogResult == DialogResult.Cancel) { return(FieldDefinitions); } } else if (promptMergeAll && mergeAll) { // merge all removed.Add(existing); updated.Add(importedFieldDefinition); } } else { updated.Add(importedFieldDefinition); } } ((List <IFieldDefinition>)FieldDefinitions).RemoveAll(i => removed.Any(r => r.Name == i.Name)); ((List <IFieldDefinition>)FieldDefinitions).AddRange(updated); MessageBox.Show($"{importedFieldDefinitions.Count} records imported. {updated.Count - removed.Count} records added, {removed.Count} records merged, {importedFieldDefinitions.Count - updated.Count} records skipped."); return(FieldDefinitions); }