Filtering in Code

• Mar 29, 2023
• 2 minutes to read

To filter Tree List nodes in code, utilize the following API:

• TreeList.ActiveFilterString and TreeList.ActiveFilterCriteria

  Allow you to specify a string filtering expression or a CriteriaOperator object. Read the following topic for detailed information and examples: Criteria Language Syntax.

  Run Demo: Filter Data

• TreeList.CustomRowFilter

  Disable the Visible property in event arguments to hide a node that does not match your custom filter criteria.

  Run Demo: Filter Nodes Dynamicatlly

• Add method of the TreeList.ActiveFilter property.

  Add a new filter criteria that applies filtering by a specific Tree List column.

  Run Demo: Filter by Specific Column

• TreeList.SetAutoFilterValue

  Enters a predefined automatic filtering row condition.

  Run Demo: Auto Filter Row

Disable the TreeListOptionsCustomization.AllowFilter option to prevent a user from applying and changing Tree List filters at runtime.

Turn off the TreeList.ActiveFilterEnabled setting to temporarily disable applied filters.

Example

The example below ensures that Tree List records with the 15% discount are always visible, regardless of the currently applied filtering condition.

C#

private void TreeList1_CustomRowFilter(object sender, CustomRowFilterEventArgs e) {
    TreeList treeList = sender as TreeList;
    string discount = treeList.GetRowCellDisplayText(e.Node, treeList.Columns["Discount"]);
    if (discount == "15%") {
        e.Visible = true;
        e.Handled = true;
    }
}

VB.NET

Private Sub TreeList1_CustomRowFilter(ByVal sender As Object, ByVal e As CustomRowFilterEventArgs)
    Dim treeList As TreeList = TryCast(sender, TreeList)
    Dim discount As String = treeList.GetRowCellDisplayText(e.Node, treeList.Columns("Discount"))
    If discount = "15%" Then
        e.Visible = True
        e.Handled = True
    End If
End Sub