public MainWindow() { InitializeComponent(); // create the object to call the service GraphServiceClient client = new GraphServiceClient(); //update the db with the latest info client.UpdateDB(); //populate the comboboxes cbFromNode.ItemsSource = nodeList; cbFromNode.SelectedValuePath = "Key"; cbFromNode.DisplayMemberPath = "Value"; cbFromNode.SelectedValue = 1; cbToNode.ItemsSource = nodeList; cbToNode.SelectedValuePath = "Key"; cbToNode.DisplayMemberPath = "Value"; cbToNode.SelectedValue = 2; //generate the graph GraphGenerate(); }