Error in deleting a row from gridview in asp.net using c#

protected void gridCountry_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        
        obj1.CountryId = Convert.ToInt32(gridCountry.DataKeys[e.RowIndex]["CountryId"].ToString ());
        obj1.DataDeleteInsideAllTable();
        obj1.ddlCountryListgrid(gridCountry);
    }

obj1.CountryId = Convert.ToInt32(gridCountry.DataKeys[e.RowIndex][CountryId].ToString ());

Quote:

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index