asp.NET button has an onclick event but the connection between the button and the onclick event is not made

Question

Here is the button code in the productdetails.aspx file:

    <asp:Button ID="Button2" runat="server" Text="Add to Wish List" 
                 CssClass="btn btn-success" OnClick="Button2_Click" />

Here is the onclick event in the productdetails.aspx.cs file

protected void Button2_Click(object sender, EventArgs e)
{
    if (temp != 1)
    {
        try
        {
            con.Open();
            string insertWish = "insert into wishlist (labelP, desP, priceP, QtyP, photoPath) values (@labelP, @desP, @priceP, @QtyP, @photoPath)";
            SqlCommand com = new SqlCommand(insertWish, con);
            com.Parameters.AddWithValue("@labelP", lblP.Text);
            com.Parameters.AddWithValue("@desP", desP.Text);
            com.Parameters.AddWithValue("@priceP", priceP.Text);
            com.Parameters.AddWithValue("@QtyP", QtyP.Text);
            com.Parameters.AddWithValue("@photoPath", Image1.ImageUrl);
            com.ExecuteNonQuery();
            Label.Text = "Product added to wish list sucessfully";
            con.Close();
        }
        catch (Exception ex)
        {
            Response.Write("Error: " + ex.ToString());
         }
     }
 }

When clicking the button the following error appears:

CS1061: 'productdetails_aspx' does not contain a definition for 'Button2_Click' and no accessible extension method 'Button2_Click' accepting a first argument of type 'productdetails_aspx' could be found (are you missing a using directive or an assembly reference?)

Note: the files are linked to a master page

Answer 1

Note: I do not have enough reputation to give suggestions in the comments box. So, posting the suggestions in the Answer Section.

• Check the button is added in the aspx designer file, this error causes if that file is not refreshed.
• Clean and rebuild the code.
• try changing the button naming if the above steps didn't work.