Formula in the GridView

[David Lau]

Hi

I am working on a project that requires the GridView to be editable.
Whenever the user update the retail price, the wholesale price column and margin column will be recalculated.
Is there anyway I can set formula among different columns?

Best regards
David Lau

[Vlad]

Hi David,

Please check this blog post for more info about how to achieve this:
http://blogs.telerik.com/pavelpavlov/posts/10-01-28/calculated_column_in_radgridview_for_silverlight_math_expressions.aspx

Greetings,
Vlad
the Telerik team

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[Stefan]

Hi,

It work´s fine, but what´s about when the Grid is editable (IsReadOnly-Property=false). The value in theTotal-Column is not updated automatically. Is there any method like "ReCalc" to update the values in the Total-Column after the user changes a  value in the Count or Price - column. I tried the method "Rebind" when the event CellEditEnded was fired, but it doesn´t work.
Please help I need a solution for a presentation.

Thank´s in advance.

With best regards
Stefan

[Pavel Pavlov]

Hi Stefan,

Please try calling RadGridView1.CalculateAggregates() method after updating the values.

Kind regards,
Pavel Pavlov
the Telerik team

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[Stefan]

Hi Pavel,

I fired the CalculateAggregates-Method in CellEditEnded-Event but it doesn´t work, the cell content is still the same.
When I call the Rebind-Method (later for example per Button-Click-Event) the cell content is updated and ok.
But it´s not useful to fire the Rebind-Method in CellEditEnded (this will triggers a infinite loop).

Kind regards
Stefan

[Pavel Pavlov]

Hello Stefan,

I believe In your scenario it would be bettter to perform calculations in the data layer as demonstrated in the attached project.

Let me know in case this does not work for you.

All the best,
Pavel Pavlov
the Telerik team

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[Stefan]

Hi Pavel,

Thank you. In your solution everthing works fine, but exactly the same code written in VB.NET does not update the Total-value if you change the Count-value. The Recalculate Method is fired correctly the data in the Data-Layer (Me.Total) is also ok. If you change the Price-value the value in Total-column is also ok. Please check. Thanks in advance.

Best regards
Stefan

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Net
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Animation
Imports System.Windows.Shapes
Imports System.ComponentModel
Imports Telerik.Windows.Controls.GridView
Imports Telerik.Windows.Controls


Partial Public Class MainPage
   Inherits UserControl

   Public Sub New()
      InitializeComponent()
      Dim items As New List(Of Item)()

      items.Add(New Item() With { _
       .Name = "Item1", _
       .Count = 2, _
       .Price = 10 _
      })
      items.Add(New Item() With { _
       .Name = "Item2", _
       .Count = 5, _
       .Price = 20 _
      })
      Me.gridView.ItemsSource = items
   End Sub

End Class

Public Class Item
   Implements INotifyPropertyChanged

   Public Property Name() As String
      Get
         Return m_Name
      End Get
      Set(ByVal value As String)
         m_Name = value
      End Set
   End Property
   Private m_Name As String
   Private m_price As Decimal
   Public Property Price() As Decimal
      Get
         Return Me.m_price
      End Get
      Set(ByVal value As Decimal)
         Me.m_price = value
         Recalculate()
      End Set
   End Property
   Private m_count As Integer
   Public Property Count() As Integer
      Get
         Return Me.m_count
      End Get
      Set(ByVal value As Integer)
         Me.m_count = value
         Recalculate()
      End Set
   End Property

   Private m_total As Decimal
   Public Property Total() As Decimal
      Get
         Return Me.m_total
      End Get
      Set(ByVal value As Decimal)
         Me.m_total = value
         Me.OnPropertyChanged("Total")
      End Set
   End Property

   Private Sub Recalculate()
      Me.Total = Me.Price * Me.Count
   End Sub

   Private Sub OnPropertyChanged(ByVal [property] As String)
      RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs([property]))
   End Sub

#Region "INotifyPropertyChanged Members"

   Public Event PropertyChanged As PropertyChangedEventHandler

#End Region

   Public Event PropertyChanged1(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged

End Class

[Pavel Pavlov]

Hello Stefan,

It seems the problem was in your implementation of the INotifyPropertyChanged interface.
The sample attached has some VB  code working as expected.

Kind regards,
Pavel Pavlov
the Telerik team

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[Stefan]

Hello Pavel,

You are right. I forgot:  Implements INotifyPropertyChanged.PropertyChanged
behind the declaration Public Event PropertyChanged As PropertyChangedEventHandler.
Now it works as expected. Thank´s a lot for your great assistance!!!

Best regards
Stefan