带链接按钮的评估方法 [英] Eval Method with link button

问题描述

<td align="center">
                               <asp:LinkButton ID="LinkButton4" PostBackUrl='<%# "~/ProductCatalog.aspx?ID="+Eval("ProductID") %>' runat="server"><5000</asp:LinkButton>
                           </td>

评估方法不适用于链接按钮..什么是问题

在产品目录页面上

Eval method is not working with a link button.. what is the problem

on products catalog page

string query = "Select * from Products where ProductID= '" + Request.QueryString["ID"].ToString() + "' AND UnitCost < 5000";
        //DataSet ds = new DataSet();
        DataSet ds=obj.fillgrid(query);
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind(); ;

我在该页面上收到错误消息，指出对象引用未设置为对象实例.

i am getting error on that page that object referenc not set to instance of an object

推荐答案

检查此博客
http://stackoverflow.com/questions/2637330/databinder-eval-in-c-sharp [ ^ ]
--NDK

check this blog
http://stackoverflow.com/questions/2637330/databinder-eval-in-c-sharp[^]
--NDK

请尝试以下操作:

Try following:

<asp:LinkButton ID="LinkButton1" PostBackUrl='<%# String.Format("ProductCatalog.aspx?ID={0}",Eval("ProductID")) %>' runat="server"><5000</asp:LinkButton>

另外，如果ProductID 数据类型为int，则需要使用以下代码:

In addition if your ProductID data type is int then you need to use the following code:

if(Request.QueryString["ID"]!="" && Request.QueryString["ID"]!=null){
string query = "Select * from Products where ProductID= " +Convert.ToInt32(Request.QueryString["ID"].ToString()) + " AND UnitCost < 5000";
}

更新
**************************************

在服务器端分配此属性:

UPDATED
*********************************

Assign this property at server side :

LinkButton4.PostBackUrl = "ProductCatalog.aspx?ID=" + ProductID;

或
将LinkButton 替换为HyperLink ，因为LinkButtons最初是用于回发的.

OR
Replace LinkButton by HyperLink as LinkButtons were originally designed to do a postback .

<asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%# Eval("ProductID", "ProductCatalog.aspx?ID={0}") %>'></asp:HyperLink>

让我知道你的结果.

Let me know your result.

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