经典问题：动态生成控件

[MasterLRC]

我想实现：

点击一个按钮，则自动在 TABLE中 加入一行，生成并加入一个 DropDownList 控件

可是我每点一次，总是有一个控件，原来加入行的就没有了,这可能是第点一次按钮，则页面刷新一次，把上次动态加入的给刷没了吧。

那么，我怎么保留以前加入的行呢？

[2002pine]

我做过象这样的东西，你可以用一个DataGrid ,绑定dropDownList，每按一次，将表的记录加一条就可

[MasterLRC]

不知能否给一下示例，谢谢！

[cnhgj]

public static string str = "";

//buttonclick

str += "<tr><td><asp:dropdownlist runat=\"server\" id=\"dp\"></asp:dropdownlist></td></tr>";



在要插入行的地方
<%=str%>

[流梓]

关注！

[saucer]

you need to re-create the controls created in the previous requests upon postback

[saucer]

you need to re-create the controls created in the previous requests upon postback

[windrain2001]

When you click Button, page will postback, thus origin added info will be lost.
It is the limitation of your used control.

Implement method:
use ViewState to store the grid information.

[saucer]

you need to re-create the controls created in the previous requests upon postback

for example:

<form runat=server id=form1>
<asp:Table id=tbl runat=server />
<asp:Button id=btn runat=server text=add Onclick="Add" />
</form>

<script language=C# runat=server>
int Count
{
get
{
object o = ViewState["Count"];
if (o==null)
return 0;
return (int)ViewState["Count"];
}
set
{
ViewState["Count"] = value;
}
}

DropDownList AddDDL()
{
TableRow tr = new TableRow();
TableCell tc = new TableCell();

DropDownList ddl = new DropDownList();
tc.Controls.Add(ddl);
tr.Cells.Add(tc);
tbl.Rows.Add(tr);

return ddl;
}

void PopulateDLL(DropDownList ddl)
{
for (int i=1; i <=10; i++)
ddl.Items.Add(i.ToString());
}


void Page_Load(Object sender, EventArgs e)
{
for (int i=0; i < Count; i++)
{
AddDDL();
}
}

void Add(Object sender, EventArgs e)
{
DropDownList ddl= AddDDL();
PopulateDLL(ddl);
Count++;
}

</script>

[saucer]

<form runat=server id=form1>
<asp:Table id=tbl runat=server />
<asp:Button id=btn runat=server text=add Onclick="Add" />
<asp:Button id=btn2 runat=server text=submit/>
</form>

[MasterLRC]

to cnhgj(戏子)

是个好办法！

不知道能不能响应 SelectChanged 事件。

[cnhgj]

刚刚测试了一下，这个办法不好！程序无法再次编译webcontrol，用思归大侠的办法

[MasterLRC]

到了这里我越来越自卑:```

但我会努力的。

[cnhgj]

如果你的dropdownlist不用动态绑定与创建事件的话，或者也可以用<select></select>htmlcontrol代替

[cnhgj]

如果你的dropdownlist不用动态绑定与创建事件的话，或者也可以用<select></select>htmlcontrol代替

[eagle_hb]

MARK!!