/// <summary>
    /// Checks create or modify permission.
    /// </summary>
    private void CheckPermissions()
    {
        CustomTableItem ctItem = form.EditedObject;

        // If editing item
        if (ctItem.ItemID > 0)
        {
            // Check 'Modify' permission
            if (!ctItem.CheckPermissions(PermissionsEnum.Modify, SiteContext.CurrentSiteName, MembershipContext.AuthenticatedUser))
            {
                // Show error message
                form.MessagesPlaceHolder.ClearLabels();
                form.ShowError(String.Format(GetString("customtable.permissiondenied.modify"), ctItem.ClassName));
                form.StopProcessing = true;
            }
        }
        else
        {
            // Check 'Create' permission
            if (!ctItem.CheckPermissions(PermissionsEnum.Create, SiteContext.CurrentSiteName, MembershipContext.AuthenticatedUser))
            {
                // Show error message
                form.MessagesPlaceHolder.ClearLabels();
                form.ShowError(String.Format(GetString("customtable.permissiondenied.create"), ctItem.ClassName));
                form.StopProcessing = true;
            }
        }
    }