帮我看一下以下代码的错误之处

Question

case mystr of
  'MA1':checkbox1.Checked:=true;
  'MA2':checkbox2.Checked:=true;
  'AA1':checkbox3.Checked:=true;
  'AA2':checkbox4.Checked:=true;
  'AA3':checkbox5.Checked:=true;
  'AA4':checkbox6.Checked:=true
end;

Answer 1

Case分支不能是字符.大哥你真强.

Answer 2

var
        mystr:string;
        ch:char;
begin
        mystr:='MA1';
        if copy(mystr,1,1)='M' then
        begin
                //showmessage(copy(mystr,3,1));
        end
        else if copy(myStr,1,1)='A' then
        case ord(ch=copy(mystr,3,1)) of
        49,50,51,52:showmessage(copy(mystr,3,1));
        end;
end;

Answer 3

var
        mystr:string;
        substr:string;/////////////
        ch:char;
begin
        mystr:='AA2';
        if copy(mystr,1,1)='M' then
        begin
                //showmessage(copy(mystr,3,1));
        end
        else if copy(myStr,1,1)='A' then
        begin
                substr:=copy(mystr,3,1);///////////////
                ch:=substr[1];///////////////
        case ord(ch) of///////////////
        49,50,51,52:showmessage(copy(mystr,3,1));
        end;
        end;
end;