System.Windows.Data Error: 17 : Cannot get 'Item[]' value (type 'ValidationError') from '(Validation.Errors)' (type 'ReadOnlyObservableCollection`1'). BindingExpression:Path=AdornedElement.(0)[0].ErrorContent; DataItem='AdornedElementPlaceholder' (Name='customAdorner'); target element is 'TextBlock'(Name=''); target property is 'Text' (type 'String') ArgumentOutOfRangeException:'System.ArgumentOutOfRangeException: 指定的参数已超出有效值的范围。
正确绑定方式
Path=(Validation.Errors)/ErrorContent
参考链接