To date every ListView I've had I just set ItemSource={Binding} in my Xaml and then in the .CS file I say listview.datacontext = myobject and the view loads just fine. But now I need to have a list that updates as the data updates as well. So after some research I discovered ObservableCollections and rewrote my code to use that. But I can't get my data to display when setting the listview to my dataobject.
My Xaml:
<ListView ItemsSource="{Binding Tests}" Name="DataCompareTests" Margin="0,0,5,0" Grid.Column="0">
<ListView.View>
<GridView>
<GridViewColumn Header="TestCase" Width="200" DisplayMemberBinding="{Binding name}" />
</GridView>
</ListView.View>
</ListView>
My Xaml.cs:
readonly DataCompare dataCompare = new DataCompare();
public void Execute_Click(object sender, RoutedEventArgs 开发者_如何学JAVAe)
{
var Tests = new ObservableCollection<TestCases>();
Tests = dataCompare.LoadTestCases(); //located in another class file
//DataCompareTests.DataContext = Tests;
}
If I remove the "Tests" part of the binding in my Xaml and remove the comments from the .DataContext line above, the view displays the correct information. However it's my assumption that if I want my view to update as the data does I need to specify my object in the binding. How do I properly set that? I can't seem to find the correct answer.
Thanks,
Jason
I think you need to familiarize yourself a little better with bindings and object oriented programming in general.
If you set your datacontext to your model object, ".Tests" should be a public property of that model object. Also, don't do this:
var someVariable = new SomeClassThatTakesWorkToConstruct();
someVarialbe = someOtherVariable.SomeMethod();
What you meant to do was this: var someVariable = someOtherVariable.SomeMethod();
This is for 2 good reasons 1) You are not wasting the construction of an ObservableCollection. 2) Your code will be easier to refactor (the type returned by SomeMethod can change without you having to alter your declaration of someVariable).
Edit, additional resources:
Databinding Overview You've got a path specified but no source for the binding specified.
MVVM Article Great article on using the common MVVM WPF pattern, helps you keep your code object oriented, clean, etc. even with complex UI interaction.
It would appear my concerns were pointless and I WAS doing this the proper way in the first place.
According to MSDN:
"However, if you are binding to an object that has already been created, you need to set > the DataContext in code, as in the following example. ... myListBox.DataContext = myDataSet;"
My object was already created, and I did set the DataContext in the code. All I had to do was leave the ListView ItemSource as {Binding} and each time I added to the Tests object, the list updated..
I can't believe I spent an entire day doubting I was doing this correctly without moving forward to check. :-)
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