StrategyBaseConverter Class

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StrategyBaseConverter Class

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Definition

A custom TypeConverter class handling the designed behavior of a strategy's property descriptor collection.  Use this as a base class for any custom TypeConverter you are applying to a strategy class.

 

Notes:

A working NinjaScript demo can be found through the reference sample on "Using a TypeConverter to Customize Property Grid Behavior"
When applying the custom converter, you must fully qualify the name (e.g., "NinjaTrader.NinjaScript.Strategies.MyCustomConveter")
Additional TypeConverter information can be found from the MSDN documentation
For Indicators, see the IndicatorBaseConverter class

 

 

Relevant base methods

TypeConverter.GetProperties()

When overriding GetProperties(), calling base.GetProperties() ensures that all default property grid behavior works as designed

TypeConverter.GetPropertiesSupported()

In your custom converter class, you must override GetPropertiesSupported() and return a value of true in order for your custom type converter to work

 

 

Syntax

public class StrategyBaseConverter : TypeConverter

 

Warning:  Failure to apply a type of StrategyBaseConverter on an strategy class can result in unpredictable behavior of the standard NinjaTrader WPF property grid.

 

 

Tip: Common strategy functions like Print() are not available to a type converter instance.  To debug a type converter class, you can use the AddOn Debug Concepts or attach to a debugger (recommended)

 

 

Examples

ns


//This namespace holds Strategies in this folder and is required. Do not change it.
namespace NinjaTrader.NinjaScript.Strategies
{
  // When applying the type converter, you must fully qualify the name
  [TypeConverter("NinjaTrader.NinjaScript.Strategies.MyCustomConveter")]
  public class MyCustomStrategy : Strategy
  {
    protected override void OnStateChange()
    {
        if (State == State.SetDefaults)
        {
          Name                             = "MyCustomStrategy";
        }
    }
 
    protected override void OnBarUpdate()
    {
        //Add your custom strategy logic here.
    }
  }
 
  // custom converter class for strategies
  public class MyCustomConveter : StrategyBaseConverter
  {
    // A general TypeConveter method used for converting types
    public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object component, Attribute[] attrs)
    {
        // sometimes you may need the strategy instance which actually exists on the grid
        MyCustomStrategy strategy = component as MyCustomStrategy;
 
        // base.GetProperties ensures we have all the properties (and associated property grid editors)
        // NinjaTrader internal logic handles for a given strategy
        PropertyDescriptorCollection propertyDescriptorCollection = base.GetPropertiesSupported(context)
                ? base.GetProperties(context, component, attrs) : TypeDescriptor.GetProperties(component, attrs);
 
        if (strategy == null || propertyDescriptorCollection == null)
          return propertyDescriptorCollection;
 
        // example of why you may need the instance that exists on the grid....
        if (strategy.EntryHandling == EntryHandling.UniqueEntries)
        {
          // do something in the event a property contains some value...
        }
 
        // Loop all of the properties of the strategy
        foreach (PropertyDescriptor property in propertyDescriptorCollection)
        {
          // do something with a specific property
 
          // cannot call Print() here
          // but you can call the static Output window "Process()"
          NinjaTrader.Code.Output.Process(property.Name, PrintTo.OutputTab1);
        }
 
        // must return the collection after making changes
        return propertyDescriptorCollection;
    }
 
    // Important:  This must return true otherwise the type converter will not be called
    public override bool GetPropertiesSupported(ITypeDescriptorContext context)
    { return true; }
  }
}