error c# biased classes

i am controlling biased classes separate functionality between 2 files, nonetheless i am removing an error. am i doing wrong?

a1.cs:

private biased category a
{
    private twine someproperty { { relapse "somegeneratedstring"; } }       
}

a2.cs:

private biased category a
{
    vacant somefunction()
    {
        //trying opening this.someproperty produces following compiler error, during slightest c# 2.0
        //error cs0117: 'a' does enclose construction 'someproperty'
    }
}