关于if else语句，各位高手帮忙！

代码如下，帮忙看看哪里有问题，运行的时候就卡住不动了，内存占用了百分之九十九
begin
  if str1=fieldvalues['areaname'] then
  begin
  if str2=fieldvalues['housename'] then
  begin
  str3:=fieldvalues['houseno'];
  rztvmainfrm.Items.AddChild(mynode[2],str3);
  end
  else begin
  str2:=fieldvalues['housename'];
  rztvmainfrm.Items.AddChild(mynode[1],str2);
  str3:=fieldvalues['houseno'];
  rztvmainfrm.Items.AddChild(mynode[2],str3);
  end;
  end
  else begin
  str1:=fieldvalues['areaname'];
  str2:=fieldvalues['housename'];
  str3:=fieldvalues['houseno'];
  mynode[1]:=rztvmainfrm.Items.AddChild(mynode[0],str1);
  mynode[2]:=rztvmainfrm.Items.AddChild(mynode[1],str2);
  rztvmainfrm.Items.AddChild(mynode[2],str3);
  end;
  end;

Delphi(Pascal) code

    if str1 = fieldvalues['areaname'] then
    begin
      if str2 = fieldvalues['housename'] then
      begin
        str3 := fieldvalues['houseno'];
        rztvmainfrm.Items.AddChild(mynode[2], str3);
      end
      else
      begin
        str2 := fieldvalues['housename'];
        rztvmainfrm.Items.AddChild(mynode[1], str2);
        str3 := fieldvalues['houseno'];
        rztvmainfrm.Items.AddChild(mynode[2], str3);
      end;
    end
    else
    begin
      str1 := fieldvalues['areaname'];
      str2 := fieldvalues['housename'];
      str3 := fieldvalues['houseno'];
      mynode[1] := rztvmainfrm.Items.AddChild(mynode[0], str1);
      mynode[2] := rztvmainfrm.Items.AddChild(mynode[1], str2);
      rztvmainfrm.Items.AddChild(mynode[2], str3);
    end;

你确定是以上代码的问题？？？是不是你查找的字段太多了？返回的比较慢