GridView:'Object' does not contain a definition for

Question

I have 2 error messages with my c# webform, that i can not handle by myself.

Add.aspx:

 <%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Add.aspx.cs" Inherits="keszlet_management.Add" %>
    <asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
        <p>
            <br />
        </p>
        <p>
            <asp:GridView ID="GridView1" runat="server"></asp:GridView>
        </p>
    </asp:Content>

Add.aspx.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;
using System.Configuration;
using MySql.Data.MySqlClient;

public partial class _Default : System.Web.UI.Page

{
    public object GridView1 { get; private set; }

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
            using (MySqlConnection con = new MySqlConnection(constr))
            {
                using (MySqlCommand cmd = new MySqlCommand("SELECT * FROM items"))
                {
                    using (MySqlDataAdapter sda = new MySqlDataAdapter())
                    {
                        cmd.Connection = con;
                        sda.SelectCommand = cmd;
                        using (DataTable dt = new DataTable())
                        {
                            sda.Fill(dt);
                            GridView1.DataSource = dt;
                            GridView1.DataBind();
                        }
                    }
                }
            }
        }
}

I am new in C#, so I know i have several mistakes, please focus on error messages: 1.: Severity Code Description Project File Line Suppression State Error CS1061 'object' does not contain a definition for 'DataSource' and no extension method 'DataSource' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
2.: The same message with 'DataBind'

You've defined GridView1 as type object and object does not have those methods/properties. Perhaps you should define it as GridView or try doing a cast. — Chris Dunaway

Tim Schmelter Tim Schmelter · Accepted Answer · 2016-10-07T13:52:55

The problem is that you have declared your GridView as

public object GridView1 { get; private set; }

It is a GridView so don't declare it as object, otherwise you can't use the properties or methods of a GridView but only of System.Object, or you have to cast it to GridView.

Since this is a codebehind file of an aspx file you don't need to declare it at all. It will be auto generated in the partial class that has the same name and ends with .designer.cs.

GridView:'Object' does not contain a definition for

2 Answers