How to compare GridView rows and Repeater items in ASP.Net using C# .Net

HTML

<form id="form1" runat="server">
<div>
    <asp:Repeater ID="Repeater1" runat="server">
        <ItemTemplate>
            <table cellpadding="0" cellspacing="0" width="100%">
                <tr>
                    <td width="40%">
                        <%#DataBinder.Eval(Container.DataItem, "CourseName")%>
                    </td>
                    <td width="25%">
                        <%#DataBinder.Eval(Container.DataItem, "CourseDate")%>
                    </td>
                    <td width="40%">
                        <asp:Label ID="lblCourseCode" Text='<%#DataBinder.Eval(Container.DataItem, "CourseCode")%>' runat="server" />
                    </td>
                </tr>
            </table>
        </ItemTemplate>
    </asp:Repeater>
    <br />
    <br />
    <br />
    <asp:GridView ID="GridView1" runat="server" BorderColor="#999999" BorderStyle="None"
        BorderWidth="1px" CellPadding="3" GridLines="Vertical" Height="1px" Width="676px"
        Font-Size="Smaller" AutoGenerateSelectButton="true" BackColor="White">
    </asp:GridView>
    <asp:Button Text="Compare" OnClick="Compare" runat="server" />
</div>
</form>

 Namespace

using System.Data;

 C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[3] { new DataColumn("CourseName", typeof(string)),
                        new DataColumn("CourseDate", typeof(string)),
                        new DataColumn("CourseCode",typeof(string)) });
        DataTable dt2 = new DataTable();
        dt2.Columns.AddRange(new DataColumn[3] { new DataColumn("CourseName", typeof(string)),
                        new DataColumn("CourseDate", typeof(string)),
                        new DataColumn("CourseCode",typeof(string)) });
        dt2.Rows.Add("RAFF", "30 mar 14", "PST0");
        dt2.Rows.Add("RPST", "30 mar 14", "PSTF");

        dt.Rows.Add("RAFF", "30 mar 14", "PSTF");
        dt.Rows.Add("RPST", "30 mar 14", "PST0");
        dt.Rows.Add("MFA", "29 mar 14", "AMC");

        this.Repeater1.DataSource = dt2;
        this.Repeater1.DataBind();
        this.GridView1.DataSource = dt;
        this.GridView1.DataBind();
    }

}

protected void Compare(object sender, EventArgs e)
{
    string gridValue = this.GridView1.Rows[2].Cells[2].Text;
    string repeaterValue = (this.Repeater1.Items[1].FindControl("lblCourseCode") as Label).Text;
    if (gridValue == repeaterValue)
    {
        ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Same Value')", true);
    }
    else
    {
        ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Different Value')", true);
    }
}