Linq to ADO Update data does not work

Question

I am using Linq in C# and asp.net to update data fields using method SaveChanges(); but it is not working!!! I Don't know why?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Default2 : System.Web.UI.Page
{
 private GitamarineEntities context = new GitamarineEntities();
 protected void Page_Load(object sender, EventArgs e)
 {
    var ves = context.tblVessels.First(v => v.vID == 15);
    txtNav.Text = ves.vNavEqpm;
 }
 protected void Button1_Click(object sender, EventArgs e)
 {
    var ves =  context.tblVessels.Single(v => v.vID == 15);
    ves.vNavEqpm = txtNav.Text.Trim();
    context.SaveChanges();
 }
}

Edited and still no luck

public partial class Default2 : System.Web.UI.Page
{
  protected void Page_Load(object sender, EventArgs e)
  {
    //GitamarineEntities1 contextShow = new GitamarineEntities1();
    //var vesShow = contextShow.tblVessels.First(v => v.vID == 15);
    //txtNav.Text = vesShow.vNavEqpm;
    //contextShow.Dispose();
  }

  protected void Button1_Click(object sender, EventArgs e)
  {
    GitamarineEntities1 contextUpdate = new GitamarineEntities1();

    var vesUpdate = contextUpdate.tblVessels.First(v => v.vID == 15);
    vesUpdate.vNavEqpm = txtNav.Text;
    contextUpdate.SaveChanges();
  }
}

Guys I have Changed Coding as above and still it works when I Comment out the Page_Load Coding! but this way user can't see what he/she is changing!!!

Can you add the context class to your code? Is tblVessels a DbSet<>? Confirm that on page load the text doees fill the textbox? Is the onClick event assigned to `Button1_Click`? — CularBytes, May 30 '15 at 10:15
yes it is all done! `private GitamarineEntities context = new GitamarineEntities();` is present in `public partial class Default2 : System.Web.UI.Page` — Amin Bakhtiari Far, May 30 '15 at 10:23

score 2 · Accepted Answer · answered May 31 '15 at 05:50

2

All you need to do , is just checking the IsPostBack in Page_Load. Try this:

        if (!IsPostBack)
        {
           GitamarineEntities1 contextShow = new GitamarineEntities1();
           var vesShow = contextShow.tblVessels.First(v => v.vID == 15);
           txtNav.Text = vesShow.vNavEqpm;
        }

answered May 31 '15 at 05:50

Hadi Mohammadi

314
2
5
20

Please Dear @Hadi explain my problem and tell me how it worked??? Please... I'm so grateful! Thanks again!!! – Amin Bakhtiari Far May 31 '15 at 06:45
You can find your answers [Here](http://stackoverflow.com/questions/183254/what-is-a-postback) – Hadi Mohammadi May 31 '15 at 06:54

score 0 · Answer 2 · answered May 30 '15 at 10:22

0

Considering that your text does get loaded inside the textbox, I guess there is nothing wrong with the linq to database.

Your button on your HTML page is probably not assigned to your Button_Click Event handler.

Your button should look like this:

 <asp:Button ID="button1" runat="server" Text="Button" OnClick="Button1_Click" />

Make sure it is inside a <form> element that also has the attribute runat="server"

Set a breakpoint on the event handler and see if it gets triggered. If not, then we need more code to fix this issue.

answered May 30 '15 at 10:22

CularBytes

9,924
8
76
101

all is done dear one! Im an amateur but not that much! I think the `var ves = context.tblVessels.Single(v => v.vID == 15);` is an object made from context and it is not the model it self! – Amin Bakhtiari Far May 30 '15 at 10:27
Show us the `GitamarineEntities` class – CularBytes May 30 '15 at 10:31
it is an ADO entity Model – Amin Bakhtiari Far May 30 '15 at 10:32
this model is created from the web sites database! – Amin Bakhtiari Far May 30 '15 at 10:35
What does UpdateModel(ves) do? ves != null before chaning data? – CularBytes May 30 '15 at 14:15
`updateModel` had error cause it had to be use in a gridview or other controls that get data from a model entity and here I have no such control so I deleted it! – Amin Bakhtiari Far May 30 '15 at 14:49

score 0 · Answer 3 · answered May 30 '15 at 16:47

0

What UpdateModel() is doing exactly? try to comment it out and see if vNavEqpm is updating from the text box value. Another thing to consider, try to re-initialize context again inside button click event and dispose it when you're using it, it's not really recommended to keep the connection alive like this, you're probably locking the retrieved record in PageLoad

answered May 30 '15 at 16:47

Malek A

21
5

I think your right about locking retrieved DATA! I have brought entity context inside of pageload and button! and steel no luck! – Amin Bakhtiari Far May 31 '15 at 05:19

Linq to ADO Update data does not work

3 Answers3