Simple Control Binding to objects

Simple Control Binding to objects

• 3d_developer

  Rick
   - How did you set up the bindings Did you use the Datasources Windows (see http://msdn2.microsoft.com/en-us/library/6ckyxa83.aspx)
  
   - What does the object you are binding to look like - are you implementing change events
  
   - How do you populate the objects you are binding to
  
  Let me know 
  
  mark 
  
  
  

• RajLakamana

  Hi Rene,
  
  This is about as simple as it gets. But I'm not binding to data but to an object in the same project. No problem setting up the data source and attaching it to the BindingSource and then to the control.
  
  But it's not binding. Something's missing to initiate the binding I'm guessing, but I have no idea what...
  
  At this point I'm back to my old binding classes...
  
  +++ Rick ---   

  
  

• Kevin F Jones

  Mark,
  
  At this point I'm just trying to get inbound binding to work.
  
  I have an object that's already populated through code. It's a plain POCO object with public properties and private fields and I'm binding to a couple of properties.
  
  Maybe I'm totally not getting how this databinding is supposed to work. What I need is to have my code populate the objects (and update them back to the database) - I want the databinding to manage the mapping of control to properties - ie. plain and simple Simple Control binding.
  
  I'm not really interested in having some manager object that fetches data for me <g> - I just want to bind to what's already there and keep the object in sync with what's in the controls.
  
  I've set up a DataSource to this object and bound the Binding Source to it, then use the binding source on the control. In the designer everything seems to work OK.
  
  I was assuming that's all that should be needed for a control to bind - a DataBinding set to the bindingSource and a specific property of the object.
  
  It looks to me that's not enough, since the data isn't displaying Something needs to trigger the binding
  
  What makes the the form/controls start binding in this scenario
  
  I'm looking through the links you've pointed me at (thanks) but all of that binds to datasource against a database which necessarily works a little differently.
  
  
  +++ Rick ---
  
  
  
  
  

• Ritesh Mehta306937

  Hi Rick.
  
  In what control you can't do the databinding and you custom object is Database or an object (a class in a dll)
  
  I had problems with the databinding in textbox and DataGridView Controls, but I can fixed with a few line of code, but tell me more about you project may be I can help you.
  
  Roman
  
  

• elamathi

  Ok check these llinks, I hope that help you.
  
  http://www.codeproject.com/vb/net/databindingconcepts.asp
  
  http://msdn.microsoft.com/library/default.asp url=/library/en-us/dnadvnet/html/vbnet09252001.asp
  
  Bye

  
  
  

• sniwas24x7

  If the object does not raise change notification then you will need to either set the populated object into the BindingSource or tell the BindingSource to refresh its controls (ResetCurrentItem).
  
  I wrote a simple example that does this by doing the following:
  
  1. Created a Customer class (see end of post)
  2. Built project
  3. Opened the Data Sources Window using the menu Data->Show Data Sources
  4. Selected Add New Data Source...
  5. Selected "Object"
  6. Expanded my project to find Customer and selected it and finished the wizard
  7. In the DataSources Window, Selected Customer
  8. Clicked on the Dropdown next to it and selected "Details View"
  9. Drag and Dropped Customer onto the Form
  10. This created a couple of Labels, bound TextBoxes and a CustomerBindingNavigator and CustomerBindingSource
  11. Double Clicked on the Form and added this to the Load event:
  
  

      Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
             CustomerBindingSource.DataSource = New Customer("Mark", "Boulter")
      End Sub
  
  12. Ran the Form - the TextBoxes showed the data from the Customer object
  13. Went back to the Form and added 2 buttons.
  14. In the first Button updated the Customer object
  

      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
          Dim c As Customer = CustomerBindingSource.DataSource
          c.LastName = "Jones"
      End Sub

  15. In the second Button refreshed the BindingSource:
  
      Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
          CustomerBindingSource.ResetCurrentItem()
      End Sub

  16. Ran the Form - when I click on the first button the object is updated but the UI does not update. When I click on the second button the UI does update.
  
  Hope this helps. If it does not let me know.
  
  mark
  
  P.S. I would not have had to add the ResetCurrentItem if I had implemented change notification on the Customer object.
  
  Customer object:
  
  Public Class Customer

      Private _lastName As String
      Private _firstName As String

      Public Sub New(ByVal newFirstName As String, ByVal newLastName As String)
          _firstName = newFirstName
          _lastName = newLastName
      End Sub

      Public Property FirstName() As String
          Get
              Return _firstName
          End Get
          Set(ByVal value As String)
              _firstName = value
          End Set
      End Property

      Public Property LastName() As String
          Get
              Return _lastName
          End Get
          Set(ByVal value As String)
              _lastName = value
          End Set
      End Property

  End Class

   

  
  
  

• Alx_it

  I had the same Problems. Everything seemed easy, but it didn't work. But after a few hours I finally found out what the reason is. To prevent you spending this time here's what i found out:

  Using the designer you don't set the "real" DataSource. You only define which type an object must be of to be able to bind. There's a 'typeof' in the Designer.cs!

  this.myBindingSource.DataSource = typeof(myClass);

  What you ALWAYS have to do ADDITIONALLY is to bind an instance of your object to the bindingsource by code like that:

  <BindingSourceName>.DataSource = <myClassInstanceName>

  Suddenly everything's easy again ;) And rather logical, if one thinks about it!

  Happy coding!

  
  
• Simple Control Binding to objects