[Solved] ASP.Net System.FormatException: The format of the input string is incorrect

Hello there.

With this code the value of DataKeyNames is dynamically assigned in the gridview

        string sentence = ddl.SelectedValue;
        string[] words = sentence.Split('-');
        int id = 0;

        if (words[1].ToString().Contains("36"))
        {
           gvProducts.DataKeyNames = new string[] { "ID" };                
        }
        else
        {
           gvProducts.DataKeyNames = new string[] { "sID" };

           GridViewRow gvrow = (sender as ImageButton).NamingContainer as GridViewRow;
           id = Convert.ToInt32(gvProducts.DataKeys[gvrow.RowIndex].Values[0]);
        }

Now i need to edit the gridview using an ImageButton and open in window popup new aspx page for editing row

    protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {
        string sentence = ddl.SelectedValue;
        string[] words = sentence.Split('-');
        int id = 0;

        if (words[1].ToString().Contains("36"))
        {
           gvProducts.DataKeyNames = new string[] { "ID" };                
        }
        else
        {
           gvProducts.DataKeyNames = new string[] { "sID" };

           GridViewRow gvrow = (sender as ImageButton).NamingContainer as GridViewRow;
           id = Convert.ToInt32(gvProducts.DataKeys[gvrow.RowIndex].Values[0]);
        }

        Thread.Sleep(3000);
        string queryString = "edit.aspx?sID=" + id.ToString();
        string newWin = "var Mleft = (screen.width/2)-(1200/2);" +
            "var Mtop = (screen.height/2)-(400/2);" +
            "window.open('" + queryString + "','_blank','height=400,width=1200," +
            "status=yes,toolbar=no,scrollbars=yes,menubar=no,location=no," +
            "top=\'+Mtop+\', left=\'+Mleft+\';');";
        ScriptManager.RegisterStartupScript(this, typeof(string), "OpenWindow", newWin, true);
    }

But i have error on this line

id = Convert.ToInt32(gvProducts.DataKeys[gvrow.RowIndex].Values[0]);

error

System.FormatException: 'The format of the input string is incorrect.'

help to do it, please.