XML Comments for nullable 2D Array

Question

How do I correct specify the XML Comments for a 2D array of nullable doubles? The following gives me syntax error.

/// <returns>The <see cref="double[,]"/>.</returns>
public double?[,] Get2DArray()
{
    ...
}

If it was just a 2D array of doubles I'd use:

/// <returns>The <see cref="double{T,T}]"/>.</returns>
public double[,] Get2DArray()
{
    ...
}

and if was just a single value I'd use:

/// <returns>The <see cref="Nullable{Double}"/>.</returns>
public static double? GetNullableDouble()
{

I can't seem to combine these two concepts to get the correct comments.

Answer 1

After reading here, perhaps you want,

/// <summary>
/// Gets the 2D Array
/// </summary>
/// <returns>The <see cref="T:double?[,]"/>.</returns>
public double?[,] Get2DArray()
{
    ...
}

---

As commented, rather than a multi-dimensional array (double?[,]) you should consider something jagged, the internal .Net implementation is superior. Additionaly, if you think of interfaces as promises, you should make the smallest possible promise, they are easier to keep.

Perhaps,

/// <summary>
/// Gets the 2D Array
/// </summary>
/// <returns>
/// The <see cref="T:IEnumerable{IEnumerable{double?}}"/> data.
/// </returns>    
public IEnumerable<IEnumerable<double?>> GetData()
{
    ...
}

would suffice.

Answer 2

The problem is that there is no generic array type, so there is nothing to reference. I believe this is done using compiler magic, but that's beyond my knowledge.

I looked through a bunch of the core .NET source to see if any of the cref values which talk about arrays use any generic reference and I'm not finding anything. Everything using <see cref="T:System.Array"/>.

I would recommend that your best option is to use the following format:

<returns>The 2-dimentional <see cref="System.Array"/> of <see cref="System.Nullable{System.Double}" />.</returns>