Problem Inserting Data Into A SQL Express Database

I am trying to implement a code behind page (in VB) to insert data into a sql express database but something is not right.  Any help would be greatly appreciated.  The following is the code I have:
Protected Sub SaveButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles SaveButton.Click
        Dim connString As String = "Data Source=.SQLEXPRESS;AttachDbFilename=|DataDirectory|News.mdf;Integrated Security=True;User Instance=True;Asynchronous Processing=true"
        Dim sqlInsert As String = "INSERT INTO news_Article (Heading, Story, Author, Show_on_homepage) VALUES(@heading, @story, @author, @show)"
        Dim conn As New System.Data.SqlClient.SqlConnection(connString)
        Dim cmd As New System.Data.SqlClient.SqlCommand(sqlInsert, conn)
        Dim heading = HeadingTextBox.Text
        Dim story = StoryEditor.Value
        Dim author = AuthorTextBox.Text
        Dim show = ShowHPCheckBox.Checked

        conn.Open()
        cmd.BeginExecuteNonQuery()
        conn.Close()
End Sub