对象名无效的错误应该怎么排除

LPARAMETERS cPropertyName, eNewValue, nVisiblity, cDescription
NODEFAULT
lexist=.f.
***判断增加的属性是否存在，如果存在则修改属性值，不存在则添加属性***
IF this.propertys.count>0
    FOR i=1 TO this.propertys.count
        IF this.propertys(i)==cpropertyname
            lexist=.t.
            IF TYPE("enewvalue")=="C"
                enewvalue=STREXTRACT(enewvalue,'"','"')
            ENDIF     
            this.&cpropertyname=enewvalue
        ENDIF
    ENDFOR  
ENDIF
   
*IF lexist=.f.
*    [color=#0000FF]IF VARTYPE(this.&cpropertyname)#"U"[/color]
*        cpropertyname[color=#808080]=cpropertyname+"1"[/color]
*    ENDIF
*    DODEFAUL(cpropertyname,enewvalue)
*    this.propertys.[color=#0000FF]add(cpropertyname) &&往element属性集里添加属性[/color]
*ENDIF     
IF lexist=.f.
    IF VARTYPE(this.&cpropertyname)=="U"
        DODEFAUL(cpropertyname,enewvalue)
    ELSE
        this.&cpropertyname=enewvalue
    ENDIF
    this.propertys.add(cpropertyname) &&往element属性集里添加属性
ENDIF