空指针错误？？？

[lanxing106]

大家帮我看看我这个为什么会报空指针，出现在这句代码上 LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");

<asp:DataList ID="DataList1" runat="server" OnItemCreated="DataList1_ItemCreated">
                            <ItemTemplate>
                                <div class="grzx_40">
                                    <div class="grzx_40_a">
                                        <img src="../UploadFiles/stdpic/<%# Eval("std_ImgPath")%>" width="50" height="66" /><span><a
                                            href='<%# Eval("url")+""+Eval("std_Id") %>' title='<%# Eval("std_NameCopy") %>' class="bbs_l_09"><%# Eval("std_Name")%></a></span></div>
                                    <div class="grzx_40_b">
                                        <%# Convert.ToDateTime(Eval("AddTime")).ToString("yyyy-MM-dd")%>
                                    </div>
                                    <div class="grzx_40_c">
                                        ￥<%# String.Format("{0:F}", Convert.ToDouble(Eval("std_SellPrice"))) %></div>
                                    <div class="grzx_40_d">
                                         <asp:LinkButton ID="LinkButton1" runat="server"  CommandName="buy" CommandArgument='<%# Eval("std_Id") %>' OnCommand="LinkButton1_Command"><img src="../Image/WebImg/grzx_pic_22.gif" width="70" height="25" /></asp:LinkButton> 
                                        <asp:LinkButton ID="LinkButton2" runat="server" CommandName="del" CommandArgument='<%# Eval("Id") %>' OnCommand="LinkButton2_Command"><img src="../Image/WebImg/grzx_pic_23.gif" width="70" height="25" /></asp:LinkButton>
                                   </div>
                                </div>
                            </ItemTemplate>
</asp:DataList>

    protected void DataList1_ItemCreated(object sender, DataListItemEventArgs e)
    {
        int id = Convert.ToInt32(((DataRowView)e.Item.DataItem).Row.ItemArray[1].ToString());

        Standards std = new Standards();
        std.std_Id = id;
        std.std_Type = 0;

        StandardsDAL sd = new StandardsDAL();
        DataTable dt = sd.QueryById(std);

        if (Convert.ToDouble(dt.Rows[0]["std_SellPrice"]) == 0)
        {
            LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");
            lb.Enabled = false;

        }
    }

[阿非]

LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");
lb.Enabled = false;
=>

LinkButton lb = DataList1.FindControl("LinkButton1") as LinkButton;
if(lb!=null)
{
lb.Enabled = false;
}

[nosuchtracter]

写在DataBound事件里面
LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");
你这样写的话，不查询出好多来了？
你应该一行一行查找吧

[阿非]

if(e.Item.ItemType==ListItemType.AlternatingItem||e.Item.ItemType=ListItemType.Item)
{
// do sth
}

---------------------------------

LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");
lb.Enabled = false;

=>

LinkButton lb = e.Item.FindControl("LinkButton1") as LinkButton;
if(lb!=null)
{
lb.Enabled = false;
}

[guoyongzhao]

不懂，机会留给楼下 ，jf

[lanxing106]

[Quote=引用 1 楼 sandy945 的回复:]
LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");
lb.Enabled = false;
=>

LinkButton lb = DataList1.FindControl("LinkButton1") as LinkButton;
if(lb!=null)
{
lb.Enabled = fal……
[/Quote]

protected void DataList1_ItemDataBound(object sender, DataListItemEventArgs e)
    {
        if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
        {

            int id = Convert.ToInt32(((DataRowView)e.Item.DataItem).Row.ItemArray[1].ToString());

            Standards std = new Standards();
            std.std_Id = id;
            std.std_Type = 0;

            StandardsDAL sd = new StandardsDAL();
            DataTable dt = sd.QueryById(std);

            if (Convert.ToDouble(dt.Rows[0]["std_SellPrice"]) == 0)
            {
                LinkButton lb = (LinkButton)DataList1.FindControl("LinkButton1");

                if (lb != null)
                {
                    lb.Enabled = false;
                }
            }
        }
    }

可是仍然报空指针错误？？？

[阿非]

(LinkButton)DataList1.FindControl("LinkButton1");

=>

e.Item.FindControl("LinkButton1") as LinkButton;

[lanxing106]

谢谢大家的热心，偶发分喽