Sorting and filtering not working

5 posts, 1 answers
  1. Ian
    Ian avatar
    20 posts
    Member since:
    Dec 2015

    Posted 31 Oct 2018 Link to this post

    I can't seem to make filtering and sorting work with my RadVirtualGrid. The control itself does the job mostly fine - lightning fast loading of 2000+ rows of data.

    I've reduced it to a simple example: a single form with a single RadVirtualGrid, which uses all the code form the online example, 

    Only different between my simple example and the documented one is that I don't get the objects from a DB - just make them.

    The grid populates fine - it's just the filter/sort which does nothing.

    I can get the more advanced filter/sort option events to fire OK, but I only need the simple stuff - single column sorts and single column filtering

    There's obviously something really simple I've missed -any suggestions ?


    Code is:

    Imports Telerik.WinControls.UI

    Public Class RadForm1
        Private columnNames As String() = New String() {"CompanyName", "ContactName", "ContactTitle", "Address", "PostalCode"}
        ' Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" +
        "..\..\DataSources\Nwind.mdb;Persist Security Info=True"   - NOT USED
        Private data As New List(Of Customer)()
        Private Sub VirtualGridPopulatingWithData_Load(sender As Object, e As EventArgs) Handles Me.Load
            AddHandler Me.RadVirtualGrid1.CellValueNeeded, AddressOf radVirtualGrid1_CellValueNeeded
            Me.RadVirtualGrid1.ColumnCount = columnNames.Length
        End Sub
        Private Sub radVirtualGrid1_CellValueNeeded(sender As Object, e As VirtualGridCellValueNeededEventArgs)
            If e.ColumnIndex < 0 Then
            End If
            If e.RowIndex = RadVirtualGrid.HeaderRowIndex Then
                e.Value = columnNames(e.ColumnIndex)
            End If
            If e.RowIndex < 0 Then
                e.FieldName = columnNames(e.ColumnIndex)
            End If
            If e.RowIndex >= 0 AndAlso e.RowIndex < data.Count Then
                e.Value = data(e.RowIndex)(e.ColumnIndex)
            End If
        End Sub
        Private Sub SelectData()

            data = Customer.makeData

            Me.RadVirtualGrid1.RowCount = data.Count
        End Sub
    End Class
    Public Class Customer

        Public Shared Function makeData() As List(Of Customer)
            Dim someCustomers As New List(Of Customer)
            someCustomers.Add(New Customer("1", "Company1", "Fred", "Mr", "addr1", "np7"))
            someCustomers.Add(New Customer("2", "Company2", "Bill", "Mr", "addr2", "np8"))
            someCustomers.Add(New Customer("3", "Company3", "Andi", "Mrs", "addr0", "np3"))

            Return someCustomers
        End Function

        Public Sub New(customerId As String, companyName As String, contactName As String,
        contactTitle As String, address As String, postalCode As String)
            Me.CustomerId = customerId
            Me.CompanyName = companyName
            Me.ContactName = contactName
            Me.ContactTitle = contactTitle
            Me.Address = address
            Me.PostalCode = postalCode
        End Sub

        Public Property CustomerId() As String
                Return m_CustomerId
            End Get
            Set(value As String)
                m_CustomerId = value
            End Set
        End Property
        Private m_CustomerId As String
        Public Property CompanyName() As String
                Return m_CompanyName
            End Get
            Set(value As String)
                m_CompanyName = value
            End Set
        End Property
        Private m_CompanyName As String
        Public Property ContactName() As String
                Return m_ContactName
            End Get
            Set(value As String)
                m_ContactName = value
            End Set
        End Property
        Private m_ContactName As String
        Public Property ContactTitle() As String
                Return m_ContactTitle
            End Get
            Set(value As String)
                m_ContactTitle = value
            End Set
        End Property
        Private m_ContactTitle As String
        Public Property Address() As String
                Return m_Address
            End Get
            Set(value As String)
                m_Address = value
            End Set
        End Property
        Private m_Address As String
        Public Property PostalCode() As String
                Return m_PostalCode
            End Get
            Set(value As String)
                m_PostalCode = value
            End Set
        End Property
        Private m_PostalCode As String

        Default Public ReadOnly Property Item(i As Integer) As String
                Select Case i
                    Case 0
                        Return CompanyName
                    Case 1
                        Return ContactName
                    Case 2
                        Return ContactTitle
                    Case 3
                        Return Address
                    Case 4
                        Return PostalCode
                    Case Else
                        Return [String].Empty
                End Select
            End Get
        End Property
    End Class

  2. Czeshirecat
    Czeshirecat avatar
    66 posts
    Member since:
    Jun 2016

    Posted 01 Nov 2018 Link to this post

    01.// in grid initialization
    02.Grid.AllowSorting = true;
    04.//initialize sort order
    05.var descriptor = new SortDescriptor
    06. {
    07.    PropertyName = "Surname",
    08.    Direction = ListSortDirection.Ascending
    09.  };
    10. Grid.SortDescriptors.Add(descriptor);
    11.Grid.SortChanged += OnMasterViewSortChanged;
    13.// my code is used to fire off running a sql query so it creates the 'order by' parameter, but
    14.// you can adapt it for whatever you need to sort your own table
    15.// property SortOrder is the finished string. If that's blank then in my code I set it to a default eg "surname asc"
    16.protected void OnMasterViewSortChanged(object sender, VirtualGridEventArgs e)
    17.    {
    18.        // expression returns the grid column header name and whether its asc or desc
    19.        var sortExpression = Grid.SortDescriptors.Expression;
    21.// if it's empty then it's the non asc/desc state of a column and requires some kind of default, or just don't sort
    22.        if (!string.IsNullOrWhiteSpace(sortExpression))
    23.        {
    24.          var direction = "";
    25.          var idx = sortExpression.IndexOf(" ASC", StringComparison.InvariantCultureIgnoreCase);
    26.          if (idx > -1) direction = "ASC";
    27.          else
    28.          {
    29.            idx = sortExpression.IndexOf(" DESC", StringComparison.InvariantCultureIgnoreCase);
    30.            if (idx > -1) direction = "DESC";
    31.          }
    33.          if (idx > -1)
    34.            sortExpression = sortExpression.Substring(0, idx).Trim();
    36.          var colIndex = _fieldHeaders.IndexOf(sortExpression);
    38.          if (string.IsNullOrWhiteSpace(sortExpression) || colIndex < 0)
    39.            return;
    41.          GetColumnInfo(colIndex, out var fieldName);
    43.          if (NonSortableColumnList.Contains(fieldName))
    44.          {
    45.            return;
    46.          }
    48.          var sortOrder = $"{fieldName} {direction}";
    49.          if (sortOrder == SortOrder) return;
    51.          SortOrder = sortOrder;
    52.        }
    53.        else return;
    55.    }
  3. Ian
    Ian avatar
    20 posts
    Member since:
    Dec 2015

    Posted 01 Nov 2018 Link to this post

    The key bit of information seems to be:

    Sorting and filtering only work if you make them work.

    There is NO built-in function for this, which is, I think, what I was expecting!

    @Telerik - it would be good to put this into the 'sort/filter' bits of the documentation: it's really important!

    Thanks @Czeshirecat as well - this really helped!

  4. Answer
    Dess | Tech Support Engineer, Sr.
    Dess | Tech Support Engineer, Sr.  avatar
    3991 posts

    Posted 01 Nov 2018 Link to this post

    Hello, Ian, 

    RadVirtualGrid is a grid component developed on top of Telerik Presentation Framework which provides a convenient way to implement your own data management operations and optimizes the performance when interacting with large amounts of data. RadVirtualGrid supports data sorting. Set the RadVirtualGrid.AllowSorting property to true in order to enable the user sorting feature. It is necessary to handle the SortChanged event which is fired once the SortDescriptors collection is changed. In the event handler you should extract the sorted data from the external data source. A sample approach is demonstrated in the following help article:

    RadVirtualGrid supports data filtering. Set the RadVirtualGrid.AllowFiltering property to true. It is necessary to handle the FilterChanged event which is fired once the FilterDescriptors collection is changed. In the event handler you should extract the filtered data from the external data source. You can refer to the online documentation:

    Our Demo application >> VirtualGrid examples are also quite useful for getting started experience with RadVirtualGrid

    @Claire, thank you for your reply. I have also updated your Telerik points for the community effort.

    I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

    Dess | Tech Support Engineer, Sr.
    Progress Telerik
    Get quickly onboarded and successful with your Telerik and/or Kendo UI products with the Virtual Classroom free technical training, available to all active customers. Learn More.
  5. Ian
    Ian avatar
    20 posts
    Member since:
    Dec 2015

    Posted 25 Jan 2019 Link to this post

    So i finally figured out a way of doing this simply, and I thought others might like the code.

    I have a large grid, with columns which are set at runtime, and might be >50, so sorting might be a problem.

    I have all the data stored in a list called allDiagrams:

      Private Sub gvVirtual_SortChanged(sender As Object, e As VirtualGridEventArgs) Handles gvVirtual.SortChanged
            'resort the data
            Dim sortExpression As String = gvVirtual.SortDescriptors.Expression
            'sort expression is of the form 'columnName' (space) 'ASC' or 'DESC'
        'Should have a better way of  detecting column names which have spaces....but none of mine do.
            Dim strs As String() = sortExpression.Split(" ")
            If strs.Length = 2 Then
                'simple case
                allDiagrams.OrderBy(Function(x) x.GetType().GetProperty(strs(0)).GetValue(x)).ToList()
                If strs(1) <> "ASC" Then
                End If
            End If
        End Sub

    This means I can have any number of column names, and the sort will always work.

    (how did we write code before we could Google for answers...)

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