The data source does not support server-side data paging.

<asp:GridView ID="GridView2" runat="server" GridLines="None" 
                onrowdatabound="GridView2_RowDataBound" align="center" 
        PageSize="4" onpageindexchanging="GridView2_PageIndexChanging" ShowHeaderWhenEmpty="true" AllowPaging="true" >
                <AlternatingRowStyle BackColor="White" />
                <RowStyle BackColor="#CCCCCC" />
            </asp:GridView>

protected void Page_Load(object sender, EventArgs e)
        {
            Recentinternship();
}

 protected void Recentinternship()
        {
            SqlConnection con = new SqlConnection("Data Source=jayraj-pc\\sqlexpress;Initial Catalog=Internship;Integrated Security=True;Pooling=False");
            con.Open();
            string str = "select B.CompanyLogo as ' ',A.Title,A.InternshipStartDate,A.ApplicationDeadline,A.Duration,A.InternshipCity,A.Category,A.Stipend,A.InternshipID,A.Degree,A.Branch,A.CompanyID,A.Title,A.CompanyName from Internship AS A INNER JOIN  Companies AS B ON A.CompanyID=B.CompanyID ";
            SqlCommand cmd = new SqlCommand(str, con);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            SqlDataReader dr = cmd.ExecuteReader();

            GridView2.DataSource = dr;
            GridView2.DataBind();
            //GridView2.BottomPagerRow.Visible = true;


            dr.Close();

            con.Close();

        }


 protected void GridView2_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            string str = " Category :" + e.Row.Cells[6].Text + "<br/>Duration :" + e.Row.Cells[4].Text + "<br/>InternshipCity :" + e.Row.Cells[5].Text + "<br/>Stipend :" + e.Row.Cells[7].Text + "<br/>InternshipStartDate :" + e.Row.Cells[2].Text + "<br/>ApplicationDeadline :" + e.Row.Cells[3].Text + "<br/>Required Degree :" + e.Row.Cells[9].Text + "<br/>Required Branch :" + e.Row.Cells[10].Text;
            e.Row.Cells[1].Text = str;

            //e.Row.Cells[1].Visible = false;
            //e.Row.Cells[2].Visible = false;
            e.Row.Cells[3].Visible = false;
            e.Row.Cells[4].Visible = false;
            e.Row.Cells[5].Visible = false;
            e.Row.Cells[6].Visible = false;
            e.Row.Cells[7].Visible = false;
            e.Row.Cells[8].Visible = false;
            e.Row.Cells[9].Visible = false;
            e.Row.Cells[10].Visible = false;
            e.Row.Cells[11].Visible = false;
            e.Row.Cells[12].Visible = false;
            e.Row.Cells[13].Visible = false;


            if (GridView2.Rows.Count > 0)
            {
                GridView2.HeaderRow.Cells[0].Text = " ";
                GridView2.HeaderRow.Cells[1].Text = " ";
                GridView2.HeaderRow.Cells[2].Text = " ";




            }
            Image img = new Image();
            img.ID = "abc";
            img.ImageUrl = e.Row.Cells[0].Text;
            e.Row.Cells[0].Controls.Add(img);

            Button btn = new Button();
            //btn.Text = "preview";
            e.Row.Cells[2].Controls.Add(btn);
            btn.CausesValidation = false;
            btn.Text = "View and Apply";
            if (Session.Count > 0)
            {


                btn.PostBackUrl = "Apply_internship.aspx?InternshipID=" + e.Row.Cells[8].Text + "&CompanyID=" + e.Row.Cells[11].Text + "&Title=" + e.Row.Cells[12].Text + "&CompanyName=" + e.Row.Cells[13].Text + "";
            }

            else
            {

                btn.PostBackUrl = "Apply_login.aspx";
            }

        }

  protected void GridView2_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            GridView2.PageIndex = e.NewPageIndex;
            Recentinternship();
        }