Unable to successfully submit a list of authors from listbox

[programmher]

I need to add either one author or a list or array of authors to my sql table. Here is the code that is used to insert the authors into the table:

The code from the listbox:

<asp:ListBox runat="server" ID="AuthorList" DataTextField="AuthorName" 
            DataValueField="AuthorName" DataSourceID="Authors"  SelectionMode="Multiple"/>

Datasource code:

<asp:ObjectDataSource runat="server" ID="ds_InventoriedAuthors" SelectMethod="GetAuthors" TypeName="CntyLibrary.Inventory.Authors" InsertMethod="AddAuthors">
    <InsertParameters>
        <asp:QueryStringParameter Name="AuthorID" Type="Int32" QueryStringField="id" />
        <asp:ControlParameter Name="ReqUserID" Type="Int32" ControlID="AuthorList" PropertyName="SelectedValue" />
        <asp:ProfileParameter Name="ReqBy" Type="Int32" PropertyName="ReqUserID" />
    </InsertParameters>
    <SelectParameters>
        <asp:QueryStringParameter Name="AuthorID" QueryStringField="id" Type="Int32" />
    </SelectParameters>
</asp:ObjectDataSource>

The button:

protected void btnAddAuthors(object sender, EventArgs e)
    {
        dsAddAuthors.Insert();
        lbAuthorList.ClearSelection();
        Response.Redirect(Request.Url.AbsoluteUri);
    }

The code behind:

public static void AddAuthors(Int32 AuthorID, Int32 ReqUserID, Int32 AddedByUser)
        {
            using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings[ConfigurationManager.AppSettings["AUTHORS"]].ConnectionString))
            {
                using (SqlCommand comm = new SqlCommand())
                {
                    comm.CommandText = "add_Authors";
                    comm.CommandType = CommandType.StoredProcedure;
                    comm.Connection = conn;
                    comm.Parameters.AddWithValue("authorid", AuthorID);
                    comm.Parameters.AddWithValue("Requserid", ReqUserID);
                    comm.Parameters.AddWithValue("addedbyUser", AddedByUser);
                    conn.Open();
                    comm.ExecuteNonQuery();
                    conn.Close();
                }
            }
}

[programmher]

I tried modifying my code to the below but am still unable to insert multiple values:

 protected void addAuthors_button(object sender, EventArgs e)
    {
        AddAuthors_ds.Insert();
        StringCollection sc = new StringCollection();
        foreach (ListItem item in AuthorsList.Items)
        {
            if (item.Selected)
            {

                 AddAuthors_ds.InsertParameters.Clear();
                 AddAuthors_ds.InsertParameters.Add("AuthorID", item.Text);
                AddAuthors_ds.Insert();
            }
        }
         AddAuthors_ds.Insert();
        AuthorsList.ClearSelection();
        Response.Redirect(Request.Url.AbsoluteUri);
    }

[Luk3r]

Your SQL CommandText needs to be an actual SQL command to add data to a table. Here's an example of a valid SQL command CommandText (from VB.NET)

comm.CommandText = "INSERT INTO [Table1] ([Col1], [Col2], [Col3]) VALUES ("'Col1Value', 'Col2Value', 'Col3Value')"

[programmher]

I am updating code another programmer (who left the company) wrote. The existing code uses a stored procedure. The project manager said she wants to keep it as a stored procedure instead of a SQL statement.