看来很简单的问题，就是如何给一个字符串变量赋值。200分(200分)

type
TForm1 = class(TForm)
Edit1: TEdit;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
a, b: String;
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
I: integer;
begin
for i := 1 to 2999 do
a := a + 'A';
a:= a + 'B';
b := a;
Edit1.Text := b;
end;

end.

{$R+}

to zhoufujin
$H+我在提文之前就已经试过了，他只是把申明为STRING变量都默认为长字符串
变量是可以承受3000个字符没问题。但是对于常量超过255个元素 与$h+是没有关系的
哎，如之奈何，如之奈何。

const
Str1='sdsdf';//大于255可能不行
Str2:String='sdlfklsdfl';//大于30000行不行？试试

delphi帮助中的解释如下：
This error message occurs when you declare a string type with more than 255 elements,
if you assign a string literal of more than 255 characters to a variable of type
ShortString, or when you have more than 255 characters in a single character string.

Note that you can construct long string literals spanning more than one line by using
the '+' operator to concatenate several string literals.

program Produce;
var
LongString : string[256]
(*<-- Error message here*)
begin
end.

In the example above, the length of the string is just one beyond the limit.

program Solve;
var
LongString : AnsiString
[red]//仍然不能在一行中超过255个字符,所以要想使用超长字符串，一是用资源文[/red]
[red]//件，二是用运算符＋连接，其它没有什么办法[/red]
begin
end.

The most convenient solution is to use the new long strings - then you don't even have
to spend any time thinking about what a reasonable maximum length would be.

帮助里说的是2GB都行 不过写成常量却。。。。。那么
就以这句
you don't even have to spend any time thinking about what a reasonable maximum length would be.
结束吧。
不过帖子再留几天看看大家评论

对于太长的常量，建议用字符数组来解决

字符串不就是字符数组么

奇怪，你把它定义成widestring应该就没问题了，怎么会出错

看来真是回天无力了，确认是编译器限制了。

Const
s='dssssssssssssssssssssssssssssssssdsdsds'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd'
+'sdddddddddddddddddddddddddd';

我都试过了，LuJuhe说的是对的，和DELPHI编辑器有关系！
aizb这样做可以！

问这个问题其实是为了解决这个问题
http://www.delphibbs.com/delphibbs/dispq.asp?lid=1599989
已经解决了呵呵 结果应以aizb分为最多
呵呵这个写法我也知道的.最后却证明确实是编译器的问题

火龙真人:

是3000 or 30000 ?

多人接受答案了。