C# Silverlight Datagrid - ADO.Net Data Entities CRUD?!?!

Question

Hello!

I have followed this tutorial which allowed me to create a Silverlight Datagrid that pulled back data from an SQL Server Database. My next step is to be able to perform CRUD on this set of data (hopefully via the datagrid by simply editing the fields for update etc. and having this post back). I have been informed that the datagrid needs to be set to have a "two-way binding mode" - However I am unsure of how to do this since the Xaml for the datagrid is literally - (Since the datagrid was dropped onto the Page.xaml file from the toolbox and generated automatically).

I specifically want to continue using this ADO.Net Entity Framework implementation. Can anybody offer me some advice or point me in the right direction with some samples? I would greatly appreciate it.

Kind regards.

EDIT: If you wouldn't mind having a quick glance over the content of the tutorial I linked to so that you understand exactly what my setup is that would be a great help. I'm completely new to Silverlight and essentially just want to know how to perform CRUD on a database using ADO.Net Entity Framework and a Silverlight Datagrid.

Answer 1

Goober,

I am not sure I will be answering your question, but I will show you how to bind information to the datagrid from code, and setting that information to two-way binding.

First off, here is a link that discusses the difference between one-way, one-time and two-way bindings.

There are three ways you can change the data source after an edit took place in the data grid:

First You can manually set the columns in the XAML and indicate that the binding to each variable is 'two-way'.

<data:DataGrid Name="data" AutoGenerateColumns="False">
                <data:DataGrid.Columns>
                    <data:DataGridTextColumn Header="Test"
                                             Binding="{Binding test, Mode=Two-Way}"/>
                </data:DataGrid.Columns>
    </data:DataGrid>

Second You can do the same thing in the code behind the page.

rpdata.ItemsSource = info;
rpdata.Columns.Clear();    
DataGridTextColumn user = new DataGridTextColumn();
                    user.Header = "User";
                    user.Binding = new System.Windows.Data.Binding("User");
                    user.Binding.Mode = BindingMode.TwoWay;

rpdata.Columns.Add(user);

rpdata represents the datagrid.

Third

Instead of linking each column manually, you can add the 'CellEditEnded' event to the data grid as shown below.

and in the code for the event, you can add the following code:

xt.CommitEdit();

This updates the data source.

You will have to create a new contract to your service that takes the entities that have been updated by the data grid.

[OperationContract]
public void UpdateWork(List<Assumptions> updates)

Here my entity is called 'Assumptions'.

In that Operation Contract you add the following code.

//Create a new entity datacontext
Entities ds = new Entities();


//For each of the entities in the list
foreach (Assumptions update in updates)
{
  try
  {
    //In the datacontext find the entity with the same primary key as the updated one
    var test = from x in ds.Assumptions
               where x.ID.Equals(update.ID)
               select x;

    //Update the entity
    test.First() = update;
  }
  catch (Exception e)
  {
    //If the entity does not exist, add it to the context
    ds.AddToAssumptions(update);
  }
}
//Save the context
ds.SaveChanges();

Answer 2

After Much Googling, this tutorial proved to help me do exactly what I wanted to do and was a fantastic help!

Good luck to anyone who continues with this implementation.

:-D