Spread WinForms 15
Spread Windows Forms 15.0 Product Documentation / Developer's Guide / Customizing Row or Column Interaction / Managing Filtering of Rows of User Data / Customizing Simple Filtering / Creating a Custom Filter
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Creating a Custom Filter
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You can create a custom filter that you can then include in the column filter definition collection. In order to create a custom filter, follow these steps:

  1. Create a class that inherits from FarPoint.Win.Spread.BaseFilterItem or FarPoint.Win.Spread.DefaultFilterItem.
  2. Override the DisplayName property to return the name to be displayed in the drop-down list of filter items.
  3. Override the ShowInDropDown method to specify if this filter item should be displayed in the drop-down list given the current filtered in rows.
  4. Override the Filter method to perform the filter action on the specified column.
  5. Override the Serialize and Deserialize methods. Make calls to the base.Serialize and base.Deserialize methods unless your methods handle persisting the default properties.
  6. Create a HideRowFilter or StyleRowFilter object.
  7. Add the custom filter to the custom filter’s list of the column filter definition in the row filtering object from the previous step.

For more details, refer to these members:

Example

This example creates a custom filter that filters rows with values ​​between 1000 and 5000 and sets the custom filter in the second column of the sheet.

C#
Copy Code 
[Serializable()]
public class CustomFilter : FarPoint.Win.Spread.BaseFilterItem
{
    FarPoint.Win.Spread.SheetView sv = null;
    public CustomFilter() { }
    public override string DisplayName
    {
        // String to  be displayed in the filter
        get { return "1000 to 5000"; }
    }
    public override FarPoint.Win.Spread.SheetView SheetView
    {
        set { sv = value; }
    }
    private bool IsNumeric(object ovalue)
    {
        System.Text.RegularExpressions.Regex _isNumber = new System.Text.RegularExpressions.Regex(@"^\-?\d+\.?\d*$");
        System.Text.RegularExpressions.Match m = _isNumber.Match(Convert.ToString(ovalue));
        return m.Success;
    }
    public bool IsFilteredIn(object ovalue)
    {
        bool ret = false;
        if (IsNumeric(ovalue))
        {
            if (Double.Parse(Convert.ToString(ovalue)) >= 1000 && Double.Parse(Convert.ToString(ovalue)) <= 5000)
                ret = true;
        }
        return ret;
    }
    public override bool ShowInDropDown(int columnIndex, int[] filteredInRowList)
    {
        // filteredInRowList argument is displayed in the item list only when
        // there is data that meets the filtered in row list condition.
        if (filteredInRowList == null)
        {
            for (int i = 0; i < sv.RowCount; i++)
            {
                object value = sv.GetValue(i, columnIndex);
                if (value != null)
                {
                    if (IsFilteredIn(value))
                        return true;
                }
            }
        }
        else
        {
            // Check if the current row list meets the condition
            for (int i = 0; i < filteredInRowList.Length; i++)
            {
                int row = filteredInRowList[i];
                object value = sv.GetValue(row, columnIndex);
                if (value != null)
                {
                    if (IsFilteredIn(value))
                        return true;
                }
            }
        }
        return false;
    }
    public override int[] Filter(int columnIndex)
    {
        System.Collections.ArrayList ar = new System.Collections.ArrayList();
        object val;
        for (int i = 0; i < sv.RowCount; i++)
        {
            val = sv.GetValue(i, columnIndex);
            if (IsFilteredIn(val))
                ar.Add(i); // Add row numbers to the list that match the conditions
        }
        return (Int32[])(ar.ToArray(typeof(Int32)));
    }
    public override bool Serialize(System.Xml.XmlTextWriter w)
    {
        w.WriteStartElement("CustomFilter");
        base.Serialize(w);
        w.WriteEndElement();
        return true;
    }
    public override bool Deserialize(System.Xml.XmlNodeReader r)
    {
        if (r.NodeType == System.Xml.XmlNodeType.Element)
        {
            if (r.Name.Equals("CustomFilter"))
            {
                base.Deserialize(r);
            }
        }
        return true;
    }
}
// Write the following in the code-behind.
// Create a filter column definition in the second column.
FarPoint.Win.Spread.FilterColumnDefinition fcd1 = new FarPoint.Win.Spread.FilterColumnDefinition(1,
    FarPoint.Win.Spread.FilterListBehavior.Custom | FarPoint.Win.Spread.FilterListBehavior.Default);
// Add custom filter to column definition.
fcd1.Filters.Add(new CustomFilter() { SheetView = fpSpread1.Sheets[0] });                   
// Create hidden filter.
FarPoint.Win.Spread.HideRowFilter hideRowFilter = new FarPoint.Win.Spread.HideRowFilter(fpSpread1.Sheets[0]);
hideRowFilter.AddColumn(fcd1);
fpSpread1.Sheets[0].RowFilter = hideRowFilter;
// Set test data.
fpSpread1.Sheets[0].SetValue(0, 1, 999);
fpSpread1.Sheets[0].SetValue(1, 1, 1000);
fpSpread1.Sheets[0].SetValue(2, 1, 5000);
Visual Basic
Copy Code 
<Serializable>
Public Class CustomFilter
    Inherits FarPoint.Win.Spread.BaseFilterItem
    Private sv As FarPoint.Win.Spread.SheetView = Nothing
    Public Sub New()
    End Sub
    Public Overrides ReadOnly Property DisplayName() As String
        ' String to be displayed in the filter
        Get
            Return "1000 to 5000"
        End Get
    End Property
    Public Overrides WriteOnly Property SheetView() As FarPoint.Win.Spread.SheetView
        Set
            sv = Value
        End Set
    End Property
    Private Function IsNumeric(ovalue As Object) As Boolean
        Dim _isNumber As New System.Text.RegularExpressions.Regex("^\-?\d+\.?\d*$")
        Dim m As System.Text.RegularExpressions.Match = _isNumber.Match(Convert.ToString(ovalue))
        Return m.Success
    End Function
    Public Function IsFilteredIn(ovalue As Object) As Boolean
        Dim ret As Boolean = False
        If IsNumeric(ovalue) Then
            If [Double].Parse(Convert.ToString(ovalue)) >= 1000 AndAlso [Double].Parse(Convert.ToString(ovalue)) <= 5000 Then
                ret = True
            End If
        End If
        Return ret
    End Function
    Public Overrides Function ShowInDropDown(columnIndex As Integer, filteredInRowList As Integer()) As Boolean
        ' filteredInRowList argument is displayed in the item list only when 
        ' there is data that meets the filtered in row list condition.
        If filteredInRowList Is Nothing Then
            For i As Integer = 0 To sv.RowCount - 1
                Dim value As Object = sv.GetValue(i, columnIndex)
                If value IsNot Nothing Then
                    If IsFilteredIn(value) Then
                        Return True
                    End If
                End If
            Next
        Else
            ' Check if the current row list meets the condition
            For i As Integer = 0 To filteredInRowList.Length - 1
                Dim row As Integer = filteredInRowList(i)
                Dim value As Object = sv.GetValue(row, columnIndex)
                If value IsNot Nothing Then
                    If IsFilteredIn(value) Then
                        Return True
                    End If
                End If
            Next
        End If
        Return False
    End Function
    Public Overrides Function Filter(columnIndex As Integer) As Integer()
        Dim ar As New System.Collections.ArrayList()
        Dim val As Object
        For i As Integer = 0 To sv.RowCount - 1
            val = sv.GetValue(i, columnIndex)
            If IsFilteredIn(val) Then
                ar.Add(i)
                ' Add row numbers to the list that match the conditions
            End If
        Next
        Return DirectCast(ar.ToArray(GetType(Int32)), Int32())
    End Function
    Public Overrides Function Serialize(w As System.Xml.XmlTextWriter) As Boolean
        w.WriteStartElement("CustomFilter")
        MyBase.Serialize(w)
        w.WriteEndElement()
        Return True
    End Function
    Public Overrides Function Deserialize(r As System.Xml.XmlNodeReader) As Boolean
        If r.NodeType = System.Xml.XmlNodeType.Element Then
            If r.Name.Equals("CustomFilter") Then
                MyBase.Deserialize(r)
            End If
        End If
        Return True
    End Function
End Class
' Write the following in the code-behind.
' Create a filter column definition in the second column.
Dim fcd1 As New FarPoint.Win.Spread.FilterColumnDefinition(1,
    FarPoint.Win.Spread.FilterListBehavior.Custom Or FarPoint.Win.Spread.FilterListBehavior.Default)
' Add custom filter to column definition.
fcd1.Filters.Add(New CustomFilter() With {.SheetView = FpSpread1.Sheets(0)})
' Create hidden filter.
Dim hideRowFilter As New FarPoint.Win.Spread.HideRowFilter(FpSpread1.Sheets(0))
hideRowFilter.AddColumn(fcd1)
FpSpread1.Sheets(0).RowFilter = hideRowFilter
' Set test data.
FpSpread1.Sheets(0).SetValue(0, 1, 999)
FpSpread1.Sheets(0).SetValue(1, 1, 1000)
FpSpread1.Sheets(0).SetValue(2, 1, 5000)
See Also
Understanding Simple Row Filtering
Customizing the Filter List

 

 

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