WPF ListView How to select a item from List<T>-CodePudding

I have a Listview where the datasource is a List< T > , when the content of the List< T> had changed I have to refresh the Listview and after that select the item I was selected before to refresh the Listview. This is my code that is not working well.

if (cbGroups.SelectedIndex!=-1)
  {
    _GroupSelected = (Groups)cbGroups.SelectedValue;
  }
  _ItemSource = true;
  // Refresh data source with the new records readed.
  cbGroups.ItemsSource = Groups_DB.Records;
  _ItemSource = false;
  if (cbGroups.Items.Count >= 0 && _GroupSelected != null)
  {
    _ItemSource = true;
    cbGroups.SelectedValue = _GroupSelected;
    int x = cbGroups.Items.IndexOf(_GroupSelected); // x is always -1
    _ItemSource = false;
  }

So, someone can help me?

CodePudding user response：

It seems obvious that the old _GroupSelected item is not an element of the new ItemsSource collection.

Take a look at how the properties SelectValue and SelectedValuePath work together. Then restore the selection by using an appropriate "key" property as SelectedValue.

Assuming a record has a unique Id property, set

<ListView x:Name="cbGroups" SelectedValuePath="Id" ...>

with code behind like this:

var selectedId = cbGroups.SelectedValue;
cbGroups.ItemsSource = Groups_DB.Records;
cbGroups.SelectedValue = selectedId;