如何在 asp.net(webforms) 中搜索？

Question

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`using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Giving_recipe : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\R.mdf;Integrated Security=True");
    
    protected void Page_Load(object sender, EventArgs e)
    {
        if (con.State == ConnectionState.Open)
        {
            con.Close();
        }
        con.Open();
      
    }

    protected void Button1_Click(object sender, EventArgs e)
    {

        SqlCommand cmd = con.CreateCommand();
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "select * from recipe";
        cmd.ExecuteNonQuery();
        DataTable dt = new DataTable();
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        da.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();

    }
   
}`

我正在尝试查找搜索，但 gridview1 中存在错误 错误是（当前上下文中不存在名称“GridView1”） 我怎么解决它？