Using custom Brush throwing exception

[stasha]

Hello NinjaTrader support.
I have the following code throwing exception: "The calling thread cannot access this object because a different thread owns it."

protected override void OnStateChange()
...
if (State == State.SetDefaults)
{
...
[B]BLTrendColor = new SolidColorBrush(Color.FromRgb(0, 255, 0));
BRTrendColor = new SolidColorBrush(Color.FromRgb(255, 0, 0));[/B]
}

protected override void OnBarUpdate()
{
if ((CurrentBar % 2) == 0)
[B]BarBrush = BLTrendColor;[/B]
else if ((CurrentBar % 3) == 0)
[B]BarBrush = BRTrendColor;[/B]
}

[XmlIgnore]
[Display(Name = "Bull trend", GroupName = "Color")]
public Brush BLTrendColor { get; set; }

[XmlIgnore]
[Display(Name = "Bear trend", GroupName = "Color")]
public Brush BRTrendColor { get; set; }

Please help resolve the issue. Reason I am defining properties this way is that I need to collect the Brush from a user, store it and use it certain way. this is just a sample project (attached) to locate the issue.

Note that I played extensively with built in Brushes, with properties being static etc. reaching out since ran out of options that I can think of.

Thank you in advance!

[NinjaTrader_ChelseaB]

Hello stasha,

Try freezing the solid color brush.
BLTrendColor = new SolidColorBrush(Color.FromRgb(0, 255, 0));
BLTrendColor.Freeze();

"Warning: If you do not call .Freeze() on a custom defined brush WILL eventually result in threading errors should you try to modify or access that brush after it is defined."

https://ninjatrader.com/support/helpGuides/nt8/index.html?working_with_brushes.htm#Understandingcustombrushes

"If you need to customize a new brush object, make sure to .Freeze() the brush before using it."

https://ninjatrader.com/support/helpGuides/nt8/index.html?ninjascript_best_practices.htm#Errorhandling