ExcelFilteringDataEventArgs.ClearData() Method

Removes all items from the collection of data values by which the column being processed can be filtered.

Namespace: DevExpress.XtraEditors.Filtering

Assembly: DevExpress.XtraEditors.v23.2.dll

NuGet Package: DevExpress.Win.Navigation

Declaration

C#

public bool ClearData()

VB.NET

Public Function ClearData As Boolean

Returns

Type	Description
Boolean	true if the items are successfully removed; otherwise, false.

Remarks

Use the ClearData() method to clear items in the DataItems collection.

Example

A default column filter menu contains data values available in the column. The code below shows how to populate a filter menu with custom values.

Note

The example uses the grid control. The vertical grid, tree list, and pivot grid controls provide a similar API.

In this example, the processed column contains comma-separated values that can be treated as individual tokens. The FilterPopupExcelData event allows you to populate the menu with custom tokens instead of the available data values.

C#

readonly static char[] separators = new char[] { ',', ' ' };

void OnFilterPopupExcelData(object sender, FilterPopupExcelDataEventArgs e) {
    // Create a collection of tokens based on data values.
    var tokens = new HashSet<string>();
    for(int i = 0; i < e.Values.Length; i++) {
        var parts = ((string)e.Values[i]).Split(separators, StringSplitOptions.RemoveEmptyEntries);
        for(int j = 0; j < parts.Length; j++)
            tokens.Add(parts[j]);
    }
    // Remove the default data values from the filter menu.
    e.ClearData();
    // Populate the menu with the created tokens.
    foreach(string t in tokens.OrderBy(x => x))
        e.AddData(t, t);
}

VB.NET

Private ReadOnly Shared separators() As Char = { ","c, " "c }

Private Sub OnFilterPopupExcelData(ByVal sender As Object, ByVal e As FilterPopupExcelDataEventArgs)
    ' Create a collection of tokens based on data values.
    Dim tokens = New HashSet(Of String)()
    For i As Integer = 0 To e.Values.Length - 1
        Dim parts = DirectCast(e.Values(i), String).Split(separators, StringSplitOptions.RemoveEmptyEntries)
        For j As Integer = 0 To parts.Length - 1
            tokens.Add(parts(j))
        Next j
    Next i
    ' Remove the default data values from the filter menu.
    e.ClearData()
    ' Populate the menu with the created tokens.
    For Each t As String In tokens.OrderBy(Function(x) x)
        e.AddData(t, t)
    Next t
End Sub

If you have populated the menu with custom tokens, you also must handle the following events:

• FilterPopupExcelQueryFilterCriteria — to convert the selected tokens to the corresponding filter criteria that should be applied to data (direct conversion). This conversion is processed when the user selects a token in the menu/applies the selected tokens/closes the menu.

  C#

  void OnFilterPopupExcelQueryFilterCriteria(object sender, FilterPopupExcelQueryFilterCriteriaEventArgs e) {
      var viewModel = e.Value as ICollectionValueViewModel<string>;
      var property = new OperandProperty(e.Path);
      var functions = viewModel.Values
          .Select(x => new FunctionOperator(FunctionOperatorType.Contains, property, x));
      e.FilterCriteria = CriteriaOperator.Or(functions);
  }
  

  VB.NET

  Private Sub OnFilterPopupExcelQueryFilterCriteria(ByVal sender As Object, ByVal e As FilterPopupExcelQueryFilterCriteriaEventArgs)
      Dim viewModel = TryCast(e.Value, ICollectionValueViewModel(Of String))
      Dim [property] = New OperandProperty(e.Path)
      Dim functions = viewModel.Values.Select(Function(x) New FunctionOperator(FunctionOperatorType.Contains, [property], x))
      e.FilterCriteria = CriteriaOperator.Or(functions)
  End Sub
  

• FilterPopupExcelParseFilterCriteria — to convert the applied filter criteria to the corresponding tokens that should be selected in the menu (reverse conversion). This conversion is processed when the user opens the menu.

  C#

  void OnFilterPopupExcelParseFilterCriteria(object sender, FilterPopupExcelParseFilterCriteriaEventArgs e) {
      var func = e.FilterCriteria as FunctionOperator;
      if(!ReferenceEquals(func, null))
          e.SetValue(((OperandValue)func.Operands[1]).Value);
      var group = e.FilterCriteria as GroupOperator;
      if(!ReferenceEquals(group, null)) {
          var values = group.Operands
              .OfType<FunctionOperator>()
              .Select(x => ((OperandValue)x.Operands[1]).Value);
          e.SetValues(values.ToArray());
      }
  }
  

  VB.NET

  Private Sub OnFilterPopupExcelParseFilterCriteria(ByVal sender As Object, ByVal e As FilterPopupExcelParseFilterCriteriaEventArgs)
      Dim func = TryCast(e.FilterCriteria, FunctionOperator)
      If Not ReferenceEquals(func, Nothing) Then
          e.SetValue(CType(func.Operands(1), OperandValue).Value)
      End If
      Dim group = TryCast(e.FilterCriteria, GroupOperator)
      If Not ReferenceEquals(group, Nothing) Then
          Dim values = group.Operands.OfType(Of FunctionOperator)().Select(Function(x) (CType(x.Operands(1), OperandValue)).Value)
          e.SetValues(values.ToArray())
      End If
  End Sub