private void txtLocateValueXY_LostFocus(object sender, RoutedEventArgs e) { double X; bool b = double.TryParse(txtLocateValueX.ValueTextBox.Text, out X); if (!b) { X = 0; } double Y; bool b2 = double.TryParse(txtLocateValueY.ValueTextBox.Text, out Y); if (!b2) { Y = 0; } mAction.SetLocateByXYValues(X, Y); }