Datagridview update help

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Hi everyone, I'm working on my first winforms EDM project and I'm trying to populate a Datagridview with a list of Presenters that can be updated by a user. The cols in my grid are Name and Email address(DataGridViewLinkColumn). So far I have been able to display the grid correctly but when I try to add a new row my changes are not being saved back to the DB even though I get a msgbox to say they have. Here's how I'm populating my DGV:

C#

private void frmPresenters_Load(object sender, EventArgs e)
{
  dal = new DataAccessLayer();

  try
  {
    //Get the List of Contacts from the DAL and bind to the DataGrid
    source = new BindingSource();
    source.DataSource = dal.GetPresentersList();

   this.dgvPresenters.DataSource = source;
   dgvPresenters.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
   dgvPresenters.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.AllCells;
  }
  catch (Exception ex)
  {
     MessageBox.Show(string.Format("Exception occurred: {0}", ex.Message));
  }
}

I'm unable to edit the Email address field as well (i think this may be a seperate thread)

all updates are made by clicking a button:

C#

private void btnSave_Click(object sender, EventArgs e)
{
   try
   {
      // Save object changes to the database, display a message, and refresh the form.
      this.source.EndEdit();
      //dal.entities.SaveChanges();
      MessageBox.Show("Changes saved to the database.");
      this.Refresh();
   }
   catch (Exception ex)
   {
      MessageBox.Show(ex.Message);
   }
}

Can anyone help me please?

[edit]pre tag for C# not set properly in the first code block is corrected - PES [/edit]

Posted 29-Feb-12 0:34am

pmcm

Updated 1-Mar-12 2:57am

ProEnggSoft

v3

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Comments

[no name] 29-Feb-12 15:56pm

What is "dal.GetPresentersList()" returning?

Calling EndEdit updates the underlying datasource but does not neccessarily save changes back to the database.

pmcm 5-Mar-12 4:41am

"dal.GetPresentersList()" was returning a List object but I've amended that to now be this:
<pre lang="c#">
public ObjectResult<Presenters> GetPresentersList()
{
// Check we have an ObjectContext
if (entities == null) entities = new CompanySecretaryEntities();
// Create a query from the entityset
var query = from p in entities.Presenters
select p;

ObjectQuery<Presenters> presenters = (ObjectQuery<Presenters>)query;

return presenters.Execute(MergeOption.AppendOnly);
}</pre>

2 solutions

Solution 2

instead of populating the Datagridview with a List object I am now using the following as my Datagridview.datasource

C#

public ObjectResult<presenters> GetPresentersList()
{
   // Check we have an ObjectContext
   if (entities == null) entities = new CompanySecretaryEntities();
      // Create a query from the entityset
      var query = from p in entities.Presenters
	          select p;
		
      ObjectQuery<presenters> presenters = (ObjectQuery<presenters>)query;

      return presenters.Execute(MergeOption.AppendOnly);
}</presenters></presenters></presenters>

Posted 5-Mar-12 5:18am

pmcm

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Caleb McElrath · Accepted Answer · 2012-03-01T02:22:00

As mentioned by Wes Aday, calling EndEdit from the DataGridView instance does not save changes to the database. To do that you can use a TableAdapter. Calling its Update method will save changes to the database.

How to insert, update, delete using DataGrid[^]

Updating data in SQL using datagridview in VS C# Windows Form[^]

DataGridView with Detail Edit Form - VS 2005[^]

Step 4: Inserting, Updating, and Deleting Data[^]

The above links are informative and provide examples.