Asp.Net Custom Server Control: PostBack handling

I wrote a custom server control. The data in it can be manipulated on the client and the changes will be written into the hidden field. The data represents a property of the control and should be retrieved on a postback. I achieved this by using the value changed event to set the property and all its dependencies. Is this a good a way to do this? Or can this code be improved?

public class Control : CompositeControl {

  private bool mProperty;
  private HiddenField hiddenField;


  public virtual bool Property {
    get {
      return mProperty;
    }
    set {
      mProperty = value;
      if (contentPanel != null) contentPanel.Visible = value;
      if (hiddenField != null && hiddenField.Value != value.ToString().ToLower()) hiddenField.Value = value.ToString().ToLower();
    }
  }
  protected override void CreateChildControls() {
    Controls.Clear();
    CreateControlHierarchy();
    ClearChildViewState();
  }
  protected virtual void CreateControlHierarchy() {
    CreateHiddenField();
    CreateContent();
  }

  protected virtual void CreateHiddenField() {
    hiddenField = new HiddenField();
    hiddenField.ID = "hiddenField";
    hiddenField.Value = Property.ToString().ToLower();
    hiddenField.ValueChanged += hiddenField_ValueChanged;
    Controls.Add(hiddenField);
  }  
  protected virtual void CreateContent() {
    contentPanel = new Panel();
    contentPanel.ID = "content";
    contentPanel.Vsiible = Property;
    Controls.Add(contentPanel);
  }
  void hiddenField_ValueChanged(object sender, EventArgs e) {
    Property = Convert.ToBoolean(hiddenField.Value);
  }
  protected override void OnInit(EventArgs e) {
    EnsureChildControls();
    base.OnInit(e);
  }
}