Get the content from database

Hi,
I am fairly new to CKEditor, want to use it in aspx page. I got no problem to integrate with asp.net.
I can easly save the content to a database. However, I am not able to get the content from database to CkEditor.
This is the aspx page

....
 <asp:TextBox ID="txt_Content" runat="server" TextMode="MultiLine"></asp:TextBox>
....
 <script type="text/javascript">
              window.onload = function() {
              var editor = CKEDITOR.replace('<% = txt_Content.ClientID %>');
             
              CKFinder.SetupCKEditor(editor, '/ckfinder/');

          };
       CKEDITOR.replace( 'txt_Content',
              {
                      filebrowserBrowseUrl : 'ckfinder/ckfinder.html',
                      filebrowserImageBrowseUrl : 'ckfinder/ckfinder.html?type=Images',
                      filebrowserFlashBrowseUrl : 'ckfinder/ckfinder.html?type=Flash',
                      filebrowserUploadUrl : 'ckfinder/core/connector/aspx/connector.aspx?command=QuickUpload&type=Files',
                      filebrowserImageUploadUrl : 'ckfinder/core/connector/aspx/connector.aspx?command=QuickUpload&type=Images',
                      filebrowserFlashUploadUrl : 'ckfinder/core/connector/aspx/connector.aspx?command=QuickUpload&type=Flash',
                      filebrowserWindowWidth : '500',
                      filebrowserWindowHeight : '500'
                } 
           );
        </script>
....

This is the codebehind, aspx.cs

  txt_Content.Text = messages.MessageContent.ToString();//the content from database.
 ///the content dont show in CkEditor

Thanks in advance