Filter ASP.Net GridView with Linq and display No records found when no data C# and VB.Net

How can i change this sql code to linq code?

Search gridview using linq

        protected void Button1_Click(object sender, EventArgs e)
        {
            DataSet ds = Search();

            if (!object.Equals(ds, null))
            {
                if (ds.Tables[0].Rows.Count > 0)
                {
                    GridView1.Visible = true;
                    textinput.Text = " ";
                    Label2.Text = " ";
                }
                else
                {
                    GridView1.Visible = false;
                    Label2.Visible = true;
                    Label2.Text = "No records available";
                }
            }
        }
        public DataSet Search()
        {
            String connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["EmpConnectionString"].ConnectionString;
            SqlConnection con = new SqlConnection(connectionString);
            string query;
            if (textinput.Text.Trim() != "")
            {

                query = "select * from Employee  where Name like'" + textinput.Text + "%'";

            }
            else
            {
                query = "select * from Employee";

            }
            SqlCommand cmd = new SqlCommand(query, con);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds);
            if (!object.Equals(ds, null))
            {
                if (ds.Tables[0].Rows.Count > 0)
                {
                    GridView1.DataSource = ds.Tables[0];
                    GridView1.DataBind();
                }

            }
            return ds;
        }

Fit this in something like this,

        protected void Button1_Click(object sender, EventArgs e)
        {
            DefaultDataContext search = new DefaultDataContext();
            var query = (from c in search.Employees
                         where c.Name.Contains(textinput.Text)
                         select c);
            GridView1.DataSource = query;
            GridView1.DataBind();
        }