The name gridview1 does not exist in the current context

问题

I am new to C#. Just following YouTube simple example and trying to simply connect to SQL database. But GridView1 gives me an error. Thes is my WebForm1.aspx.cs

using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data.OleDb;
using System.Data.Odbc;



namespace adoDemo
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            String CS = "data source =.; database = AdventureWorks2016CTP3; integrated security = SSPI";
            SqlConnection con = new SqlConnection(CS);
            SqlCommand cmd = new SqlCommand("select top 5 * from [Sales].[CreditCard]", con);
            con.Open();
            GridView1.DataSource = cmd.ExecuteReader();
            GridView1.DataBind();
            con.Close();
        }
    }
}

This is WebForm.aspx.designer.cs

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated. 
// </auto-generated>
//------------------------------------------------------------------------------

namespace adoDemo {


    public partial class WebForm1 
    {

        /// <summary>
        /// form1 control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.HtmlControls.HtmlForm form1;
    }
}

And this is WebForm1.aspx

   <script runat="server">

    Protected Sub Unnamed1_SelectedIndexChanged(sender As Object, e As EventArgs)

    End Sub
</script>
body 

<asp:gridview id="GridView1" runat="server" OnSelectedIndexChanged="Unnamed1_SelectedIndexChanged" BackColor="#DEBA84" BorderColor="#DEBA84" BorderStyle="None" BorderWidth="1px" CellPadding="3" CellSpacing="2">
    <FooterStyle BackColor="#F7DFB5" ForeColor="#8C4510" />
    <HeaderStyle BackColor="#A55129" Font-Bold="True" ForeColor="White" />
    <PagerStyle ForeColor="#8C4510" HorizontalAlign="Center" />
    <RowStyle BackColor="#FFF7E7" ForeColor="#8C4510" />
    <SelectedRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="White" />
    <SortedAscendingCellStyle BackColor="#FFF1D4" />
    <SortedAscendingHeaderStyle BackColor="#B95C30" />
    <SortedDescendingCellStyle BackColor="#F1E5CE" />
    <SortedDescendingHeaderStyle BackColor="#93451F" />
</asp:gridview>

This is how my WebForm1.aspx.designer.cs looks like

Is there anything I'm missing?

回答1:

You need to add id="GridView1" in Gridview

   <asp:gridview id="GridView1" runat="server" OnSelectedIndexChanged="Unnamed1_SelectedIndexChanged"
 BackColor="#DEBA84" BorderColor="#DEBA84" BorderStyle="None" BorderWidth="1px" CellPadding="3" CellSpacing="2">

回答2:

The page designer does sometimes refuse to add controls to the .designer.cs file; I've seen this a number of times.

If this happens, add a class-level variable yourself to the .aspx.cs: -

namespace adoDemo
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        // make sure its's the same spelling & case as in the .aspx
        protected GridView GridView1;

        protected void Page_Load(object sender, EventArgs e)
        {
            // etc
        }
    }
}

回答3:

If you're copying from a tutorial or example, make sure you've got the Namespace input correctly and that it's not the Namespace of the example.

来源：https://stackoverflow.com/questions/41257016/the-name-gridview1-does-not-exist-in-the-current-context

标签

ASP.NET

webforms