求一段简单代码
有一组复选按钮，id为CB1到CB6，将某些选中后提交其text值给一个label，如何循环实现？
                  string   str= " ";
                for   (int   i   =   1;   i   <=   6;   i++)
                {
                        str   +=   ((CheckBox)FindControl( "CB "   +   i)).Text;
                }
再赋给label时就会有错误
帮忙下


------解决方案--------------------
什么错误？？？说清楚一点！
------解决方案--------------------
是不是checkbox没有了,找不到了??? 用的进修判断一下. CheckBox chk= (CheckBox)FindControl( "CB " + i); if(chk != null) { str += chk.Text; }
------解决方案--------------------
用慕白兄的方法不会出现运行错误，但text值添加不到label ======> 因为没有checkbox所以添加不上
------解决方案--------------------
如果是VS05的话可以用CheckBoxList控件,直接按索引器访问多选框的每项,不会引发NullReferenceException.
VS03的话还是老老实实一个一个的判断是否选中吧
------解决方案--------------------
用CheckBoxList的
//aspx
<form id= "Form1 " method= "post " runat= "server ">
<asp:CheckBoxList id= "CheckBoxList1 " runat= "server " RepeatDirection= "Horizontal ">
<asp:ListItem Value= "aa "> aa </asp:ListItem>
<asp:ListItem Value= "bb "> bb </asp:ListItem>
<asp:ListItem Value= "cc "> cc </asp:ListItem>
</asp:CheckBoxList>
<asp:Button id= "Button1 " runat= "server " Text= "Button "> </asp:Button>
<asp:Label id= "Label1 " runat= "server "> </asp:Label>
</form>

//aspx.cs
private void Button1_Click(object sender, System.EventArgs e)
{
string str = string.Empty;
for(int i = 0; i < CheckBoxList1.Items.Count; i++)
{
if(CheckBoxList1.Items[i].Selected)
str += CheckBoxList1.Items[i].Text;
}
Label1.Text = str;
}
------解决方案--------------------
用CheckBox的
//aspx
<asp:checkbox id= "CheckBox1 " runat= "server " Text= "aa "> </asp:checkbox>
<asp:checkbox id= "CheckBox2 " runat= "server " Text= "bb "> </asp:checkbox>
<asp:checkbox id= "CheckBox3 " runat= "server " Text= "cc "> </asp:checkbox> <br>
<asp:button id= "Button1 " runat= "server " Text= "Button "> </asp:button>
<asp:label id= "Label1 " runat= "server "> </asp:label>

//aspx.cs
private void Button1_Click(object sender, System.EventArgs e)
{
string str = string.Empty;
for (int i = 1; i <= 3; i++)
{
CheckBox ck = (CheckBox)FindControl( "CheckBox " + i);
if(ck.Checked)
str += ck.Text;
}
Label1.Text = str;
}