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Columns
.AddRange(
    obj.GetType()
    .GetGenericArguments()
    .FirstOrDefault()?.GetProperties()

    // need the Elvis operator 
    ?.Where(p =>
    {
        return p.GetCustomAttributes(true)
                .OfType<BrowsableAttribute>()
                .FirstOrDefault()?.Browsable ?? DefaultBrowsableState;
    })

    // need the Elvis operator 
    ?.Select(p =>
    {
        return new ColumnHeader()
        {
            Name = p.Name,
            Text = p.GetCustomAttributes(true)
                    .OfType<DisplayNameAttribute>().FirstOrDefault()?.DisplayName ?? p.Name
        };
    })

    // don't need ToArray(), but need to provide a non-null value for AddRange()
    ?? Array.Empty<ColumnHeader>()
 );

Matthew Dennis wrote:

I find that adding line breaks makes it a lot easier to read

Matthew Dennis wrote:

It is missing some Elvis operators

Type.GetProperties Method (System) | Microsoft Docs[^]:

Returns
An array of PropertyInfo objects representing all public properties of the current Type.
-or-
An empty array of type PropertyInfo, if the current Type does not have public properties.

A()?.Bb()?.C().D()

static Foo A() => null;

public class Foo
{
    public Foo B() => null;
    public Foo C() => null;
    public Foo D() => null;
}

...

Foo result = A()?.B().C().D(); // result == null; no exception thrown.

Ryan Peden wrote:

Resharper catches the potential error

Ryan Peden wrote:

It even suggests a fix.

Ryan Peden wrote:

The static analysis it's doing must look at AddRange and notice that the first thing that method does is throw an exception if values is null.

p.GetCustomAttributes(true).OfType<DisplayNameAttribute>()

honey the codewitch wrote:

The LINQ isn't really that bad here.

honey the codewitch wrote:

even though I didn't write it

Marc Clifton wrote:

I believe OfType<>() is returning a null.