为什么不能选中之后 不执行插入操作那？跟datagrid和 findcontrol有关系

Question

dfat
datagrid控件如下：
<asp:datagrid id="datagrid_audience" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:TemplateColumn HeaderText="选择">
<ItemTemplate>
<asp:Label ID="p_id" Runat=server Text='<%# DataBinder.Eval(Container.DataItem,"w_username")%>' Visible=False>
</asp:Label>
<asp:CheckBox ID="chkExport" Runat="server"></asp:CheckBox>
</ItemTemplate>
</asp:TemplateColumn>
<asp:HyperLinkColumn HeaderText="听众名单" DataTextField="w_username" DataNavigateUrlField="w_username" DataNavigateUrlFormatString='seeinfo.aspx?username={0}'
Target="_blank"></asp:HyperLinkColumn>
<asp:BoundColumn DataField="u_lastlogin_date" HeaderText="最后登陆" DataFormatString="{0:D}"></asp:BoundColumn>
</Columns>
单击按钮事情如下：private void Button1_Click(object sender, System.EventArgs e)
{
CheckBox chkExport;
visitedabe MycheckBlog=new visitedabe();
MycheckBlog.OpenBase();
MycheckBlog.procedurename="insert into left_message_send(lm_send_sender,lm_send_receiver,lm_send_content) values(@str_sender,@str_receiver,@str_content)";
MycheckBlog.mysqlcommand=new SqlCommand(MycheckBlog.procedurename,MycheckBlog.myConnection);
MycheckBlog.mysqlcommand.Parameters.Add(new SqlParameter("@str_sender", SqlDbType.NVarChar,20));
MycheckBlog.mysqlcommand.Parameters.Add(new SqlParameter("@str_content", SqlDbType.NVarChar,1000));
MycheckBlog.mysqlcommand.Parameters.Add(new SqlParameter("@str_receiver", SqlDbType.NVarChar,20));
foreach(DataGridItem di in this.datagrid_audience.Items) 
{ 

chkExport=((CheckBox)di.FindControl("chkExport"));                
if(chkExport.Checked)
{
Label lbl=(Label)di.FindControl("p_id");
MycheckBlog.mysqlcommand.Parameters["@str_sender"].Value=str_name;
MycheckBlog.mysqlcommand.Parameters["@str_receiver"].Value=lbl.Text.Trim();;
MycheckBlog.mysqlcommand.Parameters["@str_content"].Value=TextBox1.Text.Trim();   
MycheckBlog.mysqlcommand.ExecuteNonQuery();
}
} 
MycheckBlog.CloseBase();
}为什么不能选中之后 不执行插入操作那

Answer 1

单步调试看每个parameters有没有值，数据库中是否已经加入，如果已经加入，确认是否grid重新绑定了。