can not add new row to child table in linq to sql RSS

• • Reply
  

  Lotfinejad

  Member

  20 Points

  13 Posts

  can not add new row to child table in linq to sql

  Jun 02, 2012 09:31 AM|LINK

  I write the below code, but i can not add any keyword to PaperKeywords table.

  Papers Table is master and Keyword is child... 

  <div>

  public partial class Author_NewSubmission : System.Web.UI.Page
  {

  string UserID;
  Guid gUID=Guid.Empty;
  SubmissionDataContext SubDC = new SubmissionDataContext();
  Paper newPaper = new Paper();
  protected void Page_Load(object sender, EventArgs e)
  {
  MembershipUser loggedinUser = Membership.GetUser();
  UserID = loggedinUser.ProviderUserKey.ToString();
  gUID = new Guid(UserID);
  newPaper.PaperTitle = "New Title";
  newPaper.UserID = gUID;
  }
  protected void btnAddKeyword_Click(object sender, EventArgs e)
  {
  PaperKeyword newPaperKeyword = new PaperKeyword();
  newPaperKeyword.Keyword =txtKeyword.Text;
  newPaper.PaperKeywords.Add(newPaperKeyword);
  if (lblKeywords.Text != "")
  lblKeywords.Text += ", " + txtKeyword.Text;
  else
  lblKeywords.Text = txtKeyword.Text;
  txtKeyword.Text = "";

  }
  protected void btnSavePaper_Click(object sender, EventArgs e)
  {
  SubDC.Papers.InsertOnSubmit(newPaper);
  SubDC.SubmitChanges();
  }
  }

  </div>
  • Edited by Lotfinejad on Jun 02, 2012 09:32 AM
  • Edited by Lotfinejad on Jun 02, 2012 09:48 AM
  • Edited by Lotfinejad on Jun 02, 2012 09:48 AM
  • Edited by Lotfinejad on Jun 02, 2012 09:48 AM
  • Edited by Lotfinejad on Jun 02, 2012 09:48 AM
• • Reply
  

  Decker Dong ...

  All-Star

  118619 Points

  18779 Posts

  Re: can not add new row to child table in linq to sql

  Jun 04, 2012 01:21 AM|LINK

  Lotfinejad

  but i can not add any keyword to PaperKeywords table.

  Hello：）

  I found that because btnSavePaper_click and AddKeyWord_Click are two different events，so everytime when you first add either of the buttons，the whole class will be rendered to be recreated again，So Paper class will be initialized again and again，which causes the problem that you can never get the original one。

  So I suggest you do this：

  public partial class Author_NewSubmission : System.Web.UI.Page
  {
  
  ……………………
  PaperKeyword newPaperKeyword = null;
  
  protected void Page_Load(object sender, EventArgs e)
  {
  ………………
  }
  protected void btnAddKeyword_Click(object sender, EventArgs e)
  {
  newPaperKeyword  = new PaperKeyword();
  newPaperKeyword.Keyword =txtKeyword.Text;
  Paper newPaper = new Paper();
  newPaper.PaperKeywords.Add(newPaperKeyword);
  if (lblKeywords.Text != "")
  lblKeywords.Text += ", " + txtKeyword.Text;
  else
  {
  lblKeywords.Text = txtKeyword.Text;
  txtKeyword.Text = "";
  }
  ViewState["np"] = newPaper;
  }
  
  protected void btnSavePaper_Click(object sender, EventArgs e)
  {
  SubDC.Papers.InsertOnSubmit(ViewState["np"] as Paper);
  SubDC.SubmitChanges();
  }
  }

  • Marked as answer by decker dong - msft on Jun 08, 2012 02:06 AM