Simple Array Declaration

[Rastus]

Hello people smarter than me,

If i want to use an array of preset length, where should I define it?

This works;

public class AA1 : Indicator
{
        private Series<double> lastMomSeries;
        private double[] testArray1 = new double[10];
}

But this doesn't.

public class AA1 : Indicator
{
        private Series<double> lastMomSeries;
        private int arrayLength = 10;
        private double[] testArray1 = new double[arrayLength];
}

I get the error CS0103
The name 'arrayLength' does not exist in the current context.

Thanks for any insight.