How can I programmatically include layout in Android?

Use a ViewStub instead of include:

<ViewStub
    android:id="@+id/layout_stub"
    android:inflatedId="@+id/message_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="0.75" />

Then in code, get a reference to the stub, set its layout resource, and inflate it:

ViewStub stub = (ViewStub) findViewById(R.id.layout_stub);
stub.setLayoutResource(R.layout.whatever_layout_you_want);
View inflated = stub.inflate();

ViewStub stub = (ViewStub) findViewById(R.id.text_post);
        stub.setLayoutResource(R.layout.profile_header);
        View inflated = stub.inflate();

In Mono.Droid / Xamarin this worked for me:

ViewStub stub = FindViewById<ViewStub>(Resource.Id.layout_stub);
stub.LayoutResource = Resource.Layout.whatever_layout_you_want;
stub.Inflate();