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Filter by using a CheckBox in RadVirtualGrid

Environment

Product Version Product Author
2020.3.1020 RadVirtualGrid for WinForms Desislava Yordanova

Description

RadVirtualGrid loads its data on demand. Hence, it doesn't know what data will be displayed and it shows the data as text. If you want to show Boolean data (true/false), it would be more appropriate to show check boxes that store the true/false value. The Creating custom cells help article demonstrates a sample approach how to create a check box data cell.

However, once the filtering functionality is enabled, we will need a check box in the filter cell to filter the data easily. This article demonstrates a sample approach how to extend the approach explained in the referred article and achieve the filtering.

filter-by-checkbox-in-virtualgrid 001

Solution

First, make sure that you have already implemented the custom data cells with check boxes: Creating custom cells.

The above illustrated result can be accomplished by following the steps below:

1. Create a derivative of VirtualGridFilterCellElement and add a RadCheckBoxElement to it in order to filter the data by its ToggleState.

2. Handle the CreateCellElement event and replace the default filter cell with the custom defined one.

3. In the ContextMenuOpening event you can add a menu item for clearing the FilterDescriptor.

DataTable dt = new DataTable();
DataView dv = new DataView();
DataTable filteredTable = new DataTable();

public RadForm1()
{
    InitializeComponent();

    dt.Columns.Add("Id",typeof(int));
    dt.Columns.Add("Name", typeof(string));
    dt.Columns.Add("Description", typeof(string));
    dt.Columns.Add("Status", typeof(bool));
    dt.Columns.Add("CreatedOn", typeof(DateTime));

    for (int i = 0; i < 50; i++)
    {
        dt.Rows.Add(i, "Row" + i, "Description" + i, i % 2 == 0, DateTime.Now.AddDays(-i));
    }
    dv = new DataView(dt);
    filteredTable = dv.ToTable();

    this.radVirtualGrid1.ColumnCount = dt.Columns.Count;
    this.radVirtualGrid1.RowCount = dt.Rows.Count;
    this.radVirtualGrid1.CellValueNeeded += radVirtualGrid1_CellValueNeeded;
    this.radVirtualGrid1.CreateCellElement += radVirtualGrid1_CreateCellElement;
    this.radVirtualGrid1.CellFormatting += RadVirtualGrid1_CellFormatting;

    this.radVirtualGrid1.MasterViewInfo.SetColumnDataType(3, typeof(int));

   this.radVirtualGrid1.ContextMenuOpening += radVirtualGrid1_ContextMenuOpening; 
    this.radVirtualGrid1.FilterChanged += RadVirtualGrid1_FilterChanged;
}

private void RadVirtualGrid1_FilterChanged(object sender, VirtualGridEventArgs e)
{ 
    dv.RowFilter = this.radVirtualGrid1.FilterDescriptors.Expression;
    filteredTable = dv.ToTable();
    dt.DefaultView.RowStateFilter = DataViewRowState.ModifiedCurrent;
    this.radVirtualGrid1.RowCount = filteredTable.Rows.Count;
} 
private void RadVirtualGrid1_CellFormatting(object sender, VirtualGridCellElementEventArgs e)
{
    if (e.CellElement.RowIndex == -3 && e.CellElement.ColumnIndex > -1)
    {
        VirtualGridFilterCellElement filterCell = e.CellElement as VirtualGridFilterCellElement;
        if (e.CellElement.ColumnIndex == 3)
        {
            filterCell.FilterOperatorText.Visibility = ElementVisibility.Collapsed;
        }
        else
        {
            filterCell.FilterOperatorText.Visibility = ElementVisibility.Visible;
        }
    }
}

private void radVirtualGrid1_CreateCellElement(object sender, VirtualGridCreateCellEventArgs e)
{
    if (e.ColumnIndex == 3)
    {
        if (e.RowIndex == -3)
        {
            e.CellElement = new MyFilterVirtualGridCheckBoxCellElement();
        }
        else if (e.RowIndex >= 0)
        {
            e.CellElement = new MyVirtualGridCheckBoxCellElement();
        }
    }

}

private void radVirtualGrid1_ContextMenuOpening(object sender, VirtualGridContextMenuOpeningEventArgs e)
{
    if (e.ColumnIndex == 3 && e.RowIndex == -3)
    { 
        e.ContextMenu.Items.Clear();

        RadMenuItem item = new RadMenuItem("Clear Filter");
        item.Click += Item_Click;
        item.Tag = e.ColumnIndex;
        e.ContextMenu.Items.Add(item);
    }

} 
private void Item_Click(object sender, EventArgs e)
{
    RadMenuItem item = sender as RadMenuItem;  
    this.radVirtualGrid1.FilterDescriptors.Remove("Status"); 
    this.radVirtualGrid1.TableElement.SynchronizeRows();
}

private void radVirtualGrid1_CellValueNeeded(object sender, VirtualGridCellValueNeededEventArgs e)
{
    if (e.ColumnIndex > -1 && e.RowIndex > -1)
    {
        e.FieldName = dt.Columns[e.ColumnIndex].ColumnName;
        e.Value = filteredTable.Rows[e.RowIndex][e.ColumnIndex];

    }
    else if (e.RowIndex == -1 && e.ColumnIndex > -1)
    {
        e.FieldName = dt.Columns[e.ColumnIndex].ColumnName;
        e.Value = filteredTable.Columns[e.ColumnIndex].ColumnName; 
    }
}

public class MyFilterVirtualGridCheckBoxCellElement : VirtualGridFilterCellElement
{
    private RadCheckBoxElement checkBox;

    protected override void CreateChildElements()
    {
        base.CreateChildElements();

        this.checkBox = new RadCheckBoxElement();
        this.Children.Add(this.checkBox);
    }


    protected override void UpdateInfo(VirtualGridCellValueNeededEventArgs args)
    {
        base.UpdateInfo(args);

        if (args.Value is bool)
        {
            this.checkBox.Checked = (bool)args.Value;
        }

        this.Text = String.Empty;
    }

    public override bool IsCompatible(int data, object context)
    {
        VirtualGridRowElement rowElement = context as VirtualGridRowElement;

        return data == 3 && rowElement.RowIndex == -3;
    }

    public override void Attach(int data, object context)
    {
        base.Attach(data, context);

        this.checkBox.ToggleStateChanged += checkBox_ToggleStateChanged;
    }

    public override void Detach()
    {
        this.checkBox.ToggleStateChanged -= checkBox_ToggleStateChanged;

        base.Detach();
    }

    protected override SizeF ArrangeOverride(SizeF finalSize)
    {
        SizeF size = base.ArrangeOverride(finalSize);

        this.checkBox.Arrange(new RectangleF((finalSize.Width - this.checkBox.DesiredSize.Width) / 2f,
            (finalSize.Height - this.checkBox.DesiredSize.Height) / 2f, this.checkBox.DesiredSize.Width, this.checkBox.DesiredSize.Height));

        return size;
    }

    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(VirtualGridCellElement);
        }
    }

    private void checkBox_ToggleStateChanged(object sender, StateChangedEventArgs args)
    {
        this.TableElement.GridElement.SetCellValue(this.checkBox.Checked, this.RowIndex, this.ColumnIndex, this.ViewInfo);

        FilterDescriptor descriptor;
        if (this.TableElement.GridElement.FilterDescriptors.Contains("Status"))
        {
            this.TableElement.GridElement.FilterDescriptors.Remove("Status");

        }

        descriptor = new FilterDescriptor("Status", FilterOperator.IsEqualTo, this.checkBox.Checked);
        this.SetFilterDescriptor(descriptor);

    }
}


Private dt As DataTable = New DataTable()
Private dv As DataView = New DataView()
Private filteredTable As DataTable = New DataTable()

Public Sub New()
    InitializeComponent()
    dt.Columns.Add("Id", GetType(Integer))
    dt.Columns.Add("Name", GetType(String))
    dt.Columns.Add("Description", GetType(String))
    dt.Columns.Add("Status", GetType(Boolean))
    dt.Columns.Add("CreatedOn", GetType(DateTime))

    For i As Integer = 0 To 50 - 1
        dt.Rows.Add(i, "Row" & i, "Description" & i, i Mod 2 = 0, DateTime.Now.AddDays(-i))
    Next

    dv = New DataView(dt)
    filteredTable = dv.ToTable()
    Me.RadVirtualGrid1.ColumnCount = dt.Columns.Count
    Me.RadVirtualGrid1.RowCount = dt.Rows.Count
    AddHandler Me.RadVirtualGrid1.CellValueNeeded, AddressOf radVirtualGrid1_CellValueNeeded
    AddHandler Me.RadVirtualGrid1.CreateCellElement, AddressOf radVirtualGrid1_CreateCellElement
    AddHandler Me.RadVirtualGrid1.CellFormatting, AddressOf RadVirtualGrid1_CellFormatting
    Me.RadVirtualGrid1.MasterViewInfo.SetColumnDataType(3, GetType(Integer))
    AddHandler Me.RadVirtualGrid1.ContextMenuOpening, AddressOf radVirtualGrid1_ContextMenuOpening
    AddHandler Me.RadVirtualGrid1.FilterChanged, AddressOf RadVirtualGrid1_FilterChanged
End Sub

Private Sub RadVirtualGrid1_FilterChanged(ByVal sender As Object, ByVal e As VirtualGridEventArgs)
    dv.RowFilter = Me.RadVirtualGrid1.FilterDescriptors.Expression
    filteredTable = dv.ToTable()
    dt.DefaultView.RowStateFilter = DataViewRowState.ModifiedCurrent
    Me.RadVirtualGrid1.RowCount = filteredTable.Rows.Count
End Sub

Private Sub RadVirtualGrid1_CellFormatting(ByVal sender As Object, ByVal e As VirtualGridCellElementEventArgs)
    If e.CellElement.RowIndex = -3 AndAlso e.CellElement.ColumnIndex > -1 Then
        Dim filterCell As VirtualGridFilterCellElement = TryCast(e.CellElement, VirtualGridFilterCellElement)

        If e.CellElement.ColumnIndex = 3 Then
            filterCell.FilterOperatorText.Visibility = ElementVisibility.Collapsed
        Else
            filterCell.FilterOperatorText.Visibility = ElementVisibility.Visible
        End If
    End If
End Sub

Private Sub radVirtualGrid1_CreateCellElement(ByVal sender As Object, ByVal e As VirtualGridCreateCellEventArgs)
    If e.ColumnIndex = 3 Then

        If e.RowIndex = -3 Then
            e.CellElement = New MyFilterVirtualGridCheckBoxCellElement()
        ElseIf e.RowIndex >= 0 Then
            e.CellElement = New MyVirtualGridCheckBoxCellElement()
        End If
    End If
End Sub

Private Sub radVirtualGrid1_ContextMenuOpening(ByVal sender As Object, ByVal e As VirtualGridContextMenuOpeningEventArgs)
    If e.ColumnIndex = 3 AndAlso e.RowIndex = -3 Then
        e.ContextMenu.Items.Clear()
        Dim item As RadMenuItem = New RadMenuItem("Clear Filter")
        AddHandler item.Click, AddressOf Item_Click
        item.Tag = e.ColumnIndex
        e.ContextMenu.Items.Add(item)
    End If
End Sub

Private Sub Item_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim item As RadMenuItem = TryCast(sender, RadMenuItem)
    Me.RadVirtualGrid1.FilterDescriptors.Remove("Status")
    Me.RadVirtualGrid1.TableElement.SynchronizeRows()
End Sub

Private Sub radVirtualGrid1_CellValueNeeded(ByVal sender As Object, ByVal e As VirtualGridCellValueNeededEventArgs)
    If e.ColumnIndex > -1 AndAlso e.RowIndex > -1 Then
        e.FieldName = dt.Columns(e.ColumnIndex).ColumnName
        e.Value = filteredTable.Rows(e.RowIndex)(e.ColumnIndex)
    ElseIf e.RowIndex = -1 AndAlso e.ColumnIndex > -1 Then
        e.FieldName = dt.Columns(e.ColumnIndex).ColumnName
        e.Value = filteredTable.Columns(e.ColumnIndex).ColumnName
    End If
End Sub

Public Class MyFilterVirtualGridCheckBoxCellElement
    Inherits VirtualGridFilterCellElement

    Private checkBox As RadCheckBoxElement

    Protected Overrides Sub CreateChildElements()
        MyBase.CreateChildElements()
        Me.checkBox = New RadCheckBoxElement()
        Me.Children.Add(Me.checkBox)
    End Sub

    Protected Overrides Sub UpdateInfo(ByVal args As VirtualGridCellValueNeededEventArgs)
        MyBase.UpdateInfo(args)

        If TypeOf args.Value Is Boolean Then
            Me.checkBox.Checked = CBool(args.Value)
        End If

        Me.Text = String.Empty
    End Sub

    Public Overrides Function IsCompatible(ByVal data As Integer, ByVal context As Object) As Boolean
        Dim rowElement As VirtualGridRowElement = TryCast(context, VirtualGridRowElement)
        Return data = 3 AndAlso rowElement.RowIndex = -3
    End Function

    Public Overrides Sub Attach(ByVal data As Integer, ByVal context As Object)
        MyBase.Attach(data, context)
        AddHandler Me.checkBox.ToggleStateChanged, AddressOf checkBox_ToggleStateChanged
    End Sub

    Public Overrides Sub Detach()
        RemoveHandler Me.checkBox.ToggleStateChanged, AddressOf checkBox_ToggleStateChanged
        MyBase.Detach()
    End Sub

    Protected Overrides Function ArrangeOverride(ByVal finalSize As SizeF) As SizeF
        Dim size As SizeF = MyBase.ArrangeOverride(finalSize)
        Me.checkBox.Arrange(New RectangleF((finalSize.Width - Me.checkBox.DesiredSize.Width) / 2.0F,
                                           (finalSize.Height - Me.checkBox.DesiredSize.Height) / 2.0F,
                                           Me.checkBox.DesiredSize.Width, Me.checkBox.DesiredSize.Height))
        Return size
    End Function

    Protected Overrides ReadOnly Property ThemeEffectiveType As Type
        Get
            Return GetType(VirtualGridCellElement)
        End Get
    End Property

    Private Sub checkBox_ToggleStateChanged(ByVal sender As Object, ByVal args As StateChangedEventArgs)
        Me.TableElement.GridElement.SetCellValue(Me.checkBox.Checked, Me.RowIndex, Me.ColumnIndex, Me.ViewInfo)
        Dim descriptor As FilterDescriptor

        If Me.TableElement.GridElement.FilterDescriptors.Contains("Status") Then
            Me.TableElement.GridElement.FilterDescriptors.Remove("Status")
        End If

        descriptor = New FilterDescriptor("Status", FilterOperator.IsEqualTo, Me.checkBox.Checked)
        Me.SetFilterDescriptor(descriptor)
    End Sub
End Class


See Also

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