How to pass complex type object to custom attribute in Blazor Server?

Question

I have custom attribute called TestAttribute.

[AttributeUsage(AttributeTargets.All)]
public class TestAttribute: Attribute
{
    IList<ComplexType> Template;
    public TestAttribute(IList<ComplexType> _template)
    {
       Template = _template;
    }
}

In my test.razor file I'm including that attribute.

@attribute [TestAttribute(myParam)]

myParam is defined in test.razor.cs file.

public IList<ComplexType> myParam = new List<ComplexType>(){
  new ComplexType {Name = "1", type="A"},
  new ComplexType {Name = "2", type="B"},
  new ComplexType {Name = "3", type="A"},
};

But it gives the error object reference is required for the non-static field, method or property. Error pops from here -> @attribute [TestAttribute(myParam)]

How can I solve this issue?