Contents
How to use observablecollection and item propertychanged?
Generally, the code responsible for displaying the data adds a PropertyChanged event handler to each object currently displayed onscreen. Instead of ObservableCollection simply use the BindingList . The following code shows a DataGrid binding to a List and to item’s properties.
Why does list need to reset if property has changed?
It is kind of draconian, because it says that the list needs to Reset rather than find the one property/item that has changed, but for small lists the performance hit should be unoticable. As you found out, there is no collection-level event that indicates that a property of an item in the collection has changed.
How to update the view when an item changes?
To update the View when each item (or FileItem, in your case) changes, the FileItem must implement INotifyPropertyChanged and fire the appropriate event when you set each property that you want to observe. Here’s an example of how to do this: http://msdn.microsoft.com/en-us/library/system.componentmodel.inotifypropertychanged.aspx
How to attach / detach to each item’s propertychanged event?
Here is how you would attach/detach to each item’s PropertyChanged event. We wrote this in the WPF-chat:
How to update the custom Datacard update property?
But there is no corresponding information mentioned in the document: I just the following, which makes the Update property showed with the collection data source. First, specifythe connected data source. Then unhide the corresponding column under Form Options,
Do you have to update all records in a collection?
For a collection, the entire record must match. Collections allow duplicate records, so multiple records might match. You can use the All argument to update all copies of a record; otherwise, only one copy of the record is updated. If the data source generates a column’s value automatically, the value of that column must be reaffirmed.
What’s the difference between the update and updateif functions?
Update function. Use the Update function to replace an entire record in a data source. In contrast, the UpdateIf and the Patch functions modify one or more values in a record, leaving the other values alone.