Compare items (Options) of two DropDownList in ASP.Net

Here I have craeted sample that count of common value form two dropdownlist.

<div>
    <asp:DropDownList ID="ddlNumbers1" runat="server">
        <asp:ListItem Text="1" Value="1" />
        <asp:ListItem Text="2" Value="2" />
        <asp:ListItem Text="3" Value="3" />
        <asp:ListItem Text="4" Value="4" />
    </asp:DropDownList>
    <br />
    <asp:DropDownList ID="ddlNumbers2" runat="server">
        <asp:ListItem Text="3" Value="3" />
        <asp:ListItem Text="4" Value="4" />
        <asp:ListItem Text="5" Value="5" />
    </asp:DropDownList>
</div>
<div>
    <asp:Button ID="btnCount" Text="Get Count" runat="server" OnClick="btnCount_Click" /><br />
    <br />
    <asp:Label ID="lblCount" runat="server" />
</div>

C#

protected void btnCount_Click(object sender, EventArgs e)
{
    int count = 0;
    string numbers = string.Empty;
    foreach (var item in ddlNumbers1.Items)
    {
        foreach (var item1 in ddlNumbers2.Items)
        {
            if (item.ToString() == item1.ToString())
            {
                count++;
                numbers = numbers + item1.ToString() + ",";
            }
        }
    }
    this.lblCount.Text = "Common values are " + count + " (" + numbers.Remove(numbers.Length - 1) + ")";
}

I hope this will help you out.