ASP.Net GridView DataBinding Error: System.Data.DataRowView does not contain a property with the name Id

I want to delete selected record but it is giving me error--System.Web.HttpException: 'DataBinding: 'System.Data.DataRowView' does not contain a property with the name 'Id'.'

<asp:GridView ID="GridView1" runat="server" CssClass="mydatagrid" PagerStyle-CssClass="pager"
    DataKeyNames="Id" HeaderStyle-CssClass="header" EmptyDataText="No Records Found"
    RowStyle-CssClass="rows" AutoGenerateColumns="False" OnRowCommand="GridView1_RowCommand">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="User ID" SortExpression="Id" ReadOnly="True"
            ItemStyle-HorizontalAlign="Center" HeaderStyle-HorizontalAlign="Center" InsertVisible="False"
            Visible="false" />
        <asp:BoundField DataField="sname" HeaderText="User Name" SortExpression="sname" ItemStyle-HorizontalAlign="Center"
            HeaderStyle-HorizontalAlign="Center" />
        <asp:BoundField DataField="date" HeaderText="Booked Date" SortExpression="date" ItemStyle-HorizontalAlign="Center"
            HeaderStyle-HorizontalAlign="Center" Visible="false" />
        <asp:BoundField DataField="spmail" HeaderText="Service Provide Email" SortExpression="spmail"
            ItemStyle-HorizontalAlign="Center" HeaderStyle-HorizontalAlign="Center" />
        <asp:BoundField DataField="status" HeaderText="Status" SortExpression="status" ItemStyle-HorizontalAlign="Center"
            HeaderStyle-HorizontalAlign="Center" />
        <asp:BoundField DataField="slot" HeaderText="Time Slot" SortExpression="slot" ItemStyle-HorizontalAlign="Center"
            HeaderStyle-HorizontalAlign="Center" />
        <asp:TemplateField ItemStyle-HorizontalAlign="Center" HeaderStyle-HorizontalAlign="Center">
            <ItemTemplate>
                <asp:ImageButton ID="ImageButton1" runat="server" Text="Delete" ImageUrl="~/Images/delete.png"
                    Width="50px" Height="50px" CommandArgument='<%# Eval("Id") %>' CommandName="Deleterow" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

void FillGrid2()
{
    string constr = ConfigurationManager.ConnectionStrings["Q_SS_regnConnectionString1"].ConnectionString;
    SqlConnection con = new SqlConnection(constr);
    SqlCommand cmd = new SqlCommand("select Id,sname,date,spmail,status,slot from Booking where semail='" + Session["mail"].ToString() + "' and status='UnApproved'", con);
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    da.Fill(dt);
    GridView1.DataSource = dt;
    GridView1.DataBind();
}
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "Deleterow")
    {
        string id = e.CommandArgument.ToString();
        string constr = ConfigurationManager.ConnectionStrings["Q_SS_regnConnectionString1"].ConnectionString;
        SqlConnection con = new SqlConnection(constr);
        con.Open();
        SqlCommand sq = new SqlCommand("DELETE FROM Booking where Id='" + id + "'", con);
        sq.ExecuteNonQuery();
        con.Close();
    }
}