C＃在类之间传递数据

Question

Just wondering how people would go about this. Say I have one class that creates and populates a Treeview which is then added to a Winform.

I have another class that is dependent upon data within the Treeview. So for example, when a user clicks on a specific node in the Treeview, class b needs that information that the node holds so that it can perform some calculation and display the result.

Would it better practise to simply pass a reference to the Treeview to the second class, or just the data that it needs? Or would it be okay to set the Treeview as static and use events so that the new class can access the treeview directly when a node is clicked on?

Thanks.

Answer 1

I would raise an event in the class that holds the treeview. That is, define a delegate and an event your class has. Then the depending class can subscribe to that event and act on the data included in the event. As I understand your question the depending class doesn't need to do anything with the treeview and should therefor not know about the treeview.

public delegate void YouControlHandler(int relevantData1, string relevantData2);
public class ClassContainingTreeView
{
    public event YouControlHandler TreeViewClickedEvent;
    public void OnTreeViewClicked(object sender, EventArgs)
    {
        // Handle request locally first and extract relevantData1/2
        if(TreeViewClickedEvent != null)
            TreeViewClickedEvent(relevantData1, relevantData2);
    }
}

public class DependingClass
{
     ClassContainingTreeView yourObject = new ClassContainingTreeView();

     public DependingClass()
     {
         yourObject.TreeViewClickedEvent += new YouControlHandler(EventHandler);
     }

     protected void EventHandler(int relevantData1, string relevantData2)
     {
             // Handle event
     }
}

Answer 2

Just pass the data.

You do not want a class to be tightly coupled to a UI control.

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As an aside, why do you think you need to make the TreeView static in order to consume events from it?

You can subscribe to an event from objects that are not static.