Data not being written to Database ASP.Net - asp.net

Question

I am building a Forum in ASP.Net but have a small problem.
I have 1 user who creates a topic and can write a post to it fine, but if another user logs in, it won't insert the post into the database. It's returning that it does but nothing inserts. The original user can login and still post but no-one else can.
this is my code in behind
protected void addPostBtn_Click(object sender, EventArgs e)
{
//Define ADO.NET objects.
string insertSQL;
string topic = Request.QueryString["topicid"].ToString();
insertSQL = "INSERT INTO Posts (TopicID, PostBody, PUserID)"
+ "VALUES (#Topic, #NewPostText, #PUserID)";
SqlConnection con = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand(insertSQL, con);
// Try to open the database and execute the update
int added = 0;
try
{
cmd.Parameters.AddWithValue("#Topic", topic);
cmd.Parameters.AddWithValue("#NewPostText", newPostText.InnerText);
cmd.Parameters.AddWithValue("#PUserID", Session["User_ID"]);
con.Open();
added = cmd.ExecuteNonQuery();
lblResults.Text = "Your post has been added";
}
catch (Exception err)
{
lblResults.Text = "Error inserting record. " + err.Message;
}
finally
{
con.Close();
}
if (added > 0)
{
this.BindRepeater();
}
}
I don't get any errors at all. It says it submitted fine, but it's not in the database unless the original poster does it.
EDIT:
Just realized it's to do with my view. This is my current view that it's reading from
SELECT dbo.Posts.PostBody, dbo.Posts.PostDate, dbo.Posts.PostID, dbo.[User].username, dbo.Topic.TopicID
FROM dbo.Topic RIGHT OUTER JOIN
dbo.Posts ON dbo.Topic.TopicID = dbo.Posts.TopicID LEFT OUTER JOIN
dbo.[User] ON dbo.Topic.TUserID = dbo.[User].UserID AND dbo.Posts.PUserID = dbo.[User].UserID
But it's returning NULL now for the other users names

Answer 1

The view needs to be as follows
SELECT dbo.Posts.PostBody, dbo.Posts.PostDate, dbo.Posts.PostID, dbo.[User].username, dbo.Topic.TopicID
FROM dbo.Topic LEFT OUTER JOIN
dbo.Posts ON dbo.Topic.TopicID = dbo.Posts.TopicID LEFT OUTER JOIN
dbo.[User] ON dbo.Posts.PUserID = dbo.[User].UserID