SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["OldConnectionString"].ConnectionString);
ForumInfo forum = ForumInfoProvider.GetForumInfo("YourForumCodeName", CMSContext.CurrentSiteID);
// get a list of all the sites users for later use
DataSet dsUsers = UserInfoProvider.GetUsers("", "");

protected void Page_Load(object sender, EventArgs e)
{
    lblMessage.Text = "";
}

protected void btnInsertPosts_Click(object sender, EventArgs e)
{
    CreateParentPosts();
}
    
private void CreateParentPosts()
{
    try
    {
        // get the old parent posts
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = cn;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "select top 20 cs_posts.*, m.Email from cs_Posts left outer join cs_users on cs_posts.UserID = cs_users.UserID left outer join aspnet_Membership m on cs_users.MembershipID = m.UserId where SectionID = 3 and parentid = -1 and settingsid = 1000 order by threadid, SortOrder, PostLevel";

        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);

        if (!DataHelper.DataSourceIsEmpty(ds))
        {
            if (forum != null)
            {
                // loop all parent posts
                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    // get the old post id
                    int oldPostId = ValidationHelper.GetInteger(dr["PostID"], -1);

                    // Create new forum post object
                    ForumPostInfo newPost = new ForumPostInfo();
                    // set values and actually insert the post
                    CreatePost(dr, ref newPost, -1);
                    // attach images/files to post
                    AttachImages(oldPostId, newPost.PostId);
                    // create the child posts
                    CreateChildPosts(oldPostId, newPost.PostId);
                }
            }
        }
    }
    catch (Exception ex)
    {
        lblMessage.Text += ex.ToString();
    }
}

private void CreateChildPosts(int OldPostId, int NewParentId)
{
    try
    {
        // get the old child records
        DataSet ReturnValue = new DataSet();
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["OldConnectionString"].ConnectionString);
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = cn;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "select m.Email, cs_posts.* from cs_Posts left outer join cs_users on cs_posts.UserID = cs_users.UserID left outer join aspnet_Membership m on cs_users.MembershipID = m.UserId where SectionID = 3 and ParentID = " + OldPostId.ToString() + " and postlevel > 1 order by threadid, SortOrder, PostLevel";

        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);

        if (!DataHelper.DataSourceIsEmpty(ds))
        {
            if (forum != null)
            {
                // loop all old child records
                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    int oldPostId = ValidationHelper.GetInteger(dr["PostID"], -1);

                    // Create new forum post object
                    ForumPostInfo newPost = new ForumPostInfo();
                    // set values and actually insert the post
                    CreatePost(dr, ref newPost, NewParentId);
                    // attach images to post
                    AttachImages(oldPostId, newPost.PostId);
                    // recursive action for child posts
                    CreateChildPosts(oldPostId, newPost.PostId);
                }
            }
        }
    }
    catch (Exception ex)
    {
        lblMessage.Text += ex.ToString();
    }
}

private void CreatePost(DataRow dr, ref ForumPostInfo newPost, int NewParentId)
{
    UserInfo ui = null;
    int kenticoUserId = 53;
    // get the old email address and attempt to match via email with a current user
    // doing this because usernames changed from one CMS to the other although email addresses remained similar
    foreach (DataRow udr in dsUsers.Tables[0].Rows)
    {
        if (ValidationHelper.GetString(udr["Email"], "") == ValidationHelper.GetString(dr["Email"], "not valid"))
        {
            kenticoUserId = ValidationHelper.GetInteger(udr["UserID"], 53);
            break;
        }
    }

    ui = UserInfoProvider.GetUserInfo(kenticoUserId);

    // set all the values of the post
    newPost.PostUserID = ui.UserID;
    newPost.PostUserMail = ui.Email;
    newPost.PostUserName = ui.UserName;
    newPost.PostForumID = forum.ForumID;
    newPost.PostTime = ValidationHelper.GetDateTime(dr["PostDate"], DateTime.Now);
    newPost.PostApproved = true;
    newPost.PostText = HTMLHelper.StripTags(ValidationHelper.GetString(dr["Body"], ""), false, "");
    newPost.PostSubject = HTMLHelper.StripTags(ValidationHelper.GetString(dr["Subject"], ""), false, "");
    newPost.PostLevel = ValidationHelper.GetInteger(dr["PostLevel"], 1);
    newPost.PostViews = ValidationHelper.GetInteger(dr["TotalViews"], 0);
        
    // do some checking to see if this is a parent record or not
    if (NewParentId > -1)
    {
        newPost.PostParentID = NewParentId;
    }
    // Save the forum post
    ForumPostInfoProvider.SetForumPostInfo(newPost);
}

private void AttachImages(int OldPostId, int NewPostId)
{
    // get the physical path on the server D:\Apps\Site\3\PostID
    string path = HostingEnvironment.ApplicationPhysicalPath + @"3\" + OldPostId.ToString() + @"\";
    if (CMS.IO.Directory.Exists(path))
    {
        // get all the files in the directory
        // might need to filter by *.jpg but previous app already did that so no worries
        string[] files = CMS.IO.Directory.GetFiles(path);
        // for every file in the directory, create a new forum attachment
        foreach (string s in files)
        {
            ForumAttachmentInfo attachInfo = new ForumAttachmentInfo(s, 0, 0, 1000);
            attachInfo.AttachmentPostID = NewPostId;
            attachInfo.AttachmentSiteID = 3;
            ForumAttachmentInfoProvider.SetForumAttachmentInfo(attachInfo);
        }
    }        
}