ASPxTreeList.GetSelectedNodes() Method

Returns a list of selected nodes.

Namespace: DevExpress.Web.ASPxTreeList

Assembly: DevExpress.Web.ASPxTreeList.v24.2.dll

Declaration

C#

public List<TreeListNode> GetSelectedNodes()

VB.NET

Public Function GetSelectedNodes As List(Of TreeListNode)

Returns

Type	Description
List<TreeListNode>	The list of TreeListNode objects that represent nodes currently being selected.

Remarks

A node is selected if its TreeListNode.Selected property is set to true. End-users can select nodes via check boxes displayed within selection cells.

To learn more, see Selection.

Note

In virtual mode, the GetSelectedNodes method does not return invisible nodes. To learn more, see the Virtual Mode topic.

The code sample below demonstrates tow to store the selection between requests.

<dx:ASPxTreeList ID="treeList" runat="server" ClientInstanceName="treeList" AutoGenerateColumns="False"
    KeyFieldName="ItemId" ParentFieldName="ParentId" KeyboardSupport="True" OnDataBinding="atlSelection_DataBinding" OnCustomCallback="treeList_CustomCallback">
    <Columns>
        <dx:TreeListTextColumn FieldName="Code" />
        <dx:TreeListTextColumn FieldName="Name" />
        <dx:TreeListTextColumn FieldName="Description" />
        <dx:TreeListTextColumn FieldName="ItemType" />
        <dx:TreeListTextColumn FieldName="Price" >
            <PropertiesTextEdit DisplayFormatString="{0:C}" />
        </dx:TreeListTextColumn>
    </Columns>
    <SettingsPager PageSize="20" Mode="ShowPager" />
    <SettingsBehavior AllowFocusedNode="true" AutoExpandAllNodes="True" 
                      AllowSort="False" FocusNodeOnExpandButtonClick="true" />
    <SettingsSelection Enabled="True" />
    <SettingsEditing AllowNodeDragDrop="true" Mode="EditForm" />
</dx:ASPxTreeList>

<dx:ASPxButton ID="ASPxButton1" runat="server" Text="Save selection" AutoPostBack="false">
    <ClientSideEvents Click="function (s, e) { treeList.PerformCallback('Save'); }" />
</dx:ASPxButton>
<dx:ASPxButton ID="ASPxButton2" runat="server" Text="Restore selection" AutoPostBack="false">
    <ClientSideEvents Click="function (s, e) { treeList.PerformCallback('Restore'); }" />
</dx:ASPxButton>

C#

private const string selectedNodesKey = "selectedNodesKey";

protected void treeList_CustomCallback(object sender, TreeListCustomCallbackEventArgs e) {
    switch (e.Argument) {
        case "Save":
            SaveSelection();
            break;
        case "Restore":
            RestoreSelection();
            break;
    }
}
private void SaveSelection() {
    Session[selectedNodesKey] = treeList.GetSelectedNodes().Select(node => node.Key);
}
private void RestoreSelection() {
    if (Session[selectedNodesKey] == null)
        return;
    var rowKeys = (IEnumerable<string>)Session[selectedNodesKey];
    var iterator = treeList.CreateNodeIterator();
    iterator.Reset();

    while (iterator.Current != null) {
        iterator.Current.Selected = rowKeys.Contains(iterator.Current.Key);
        iterator.GetNext();
    }
}

VB.NET

Private Const selectedNodesKey As String = "selectedNodesKey"

Protected Sub treeList_CustomCallback(ByVal sender As Object, ByVal e As TreeListCustomCallbackEventArgs)
    Select Case e.Argument
        Case "Save"
            SaveSelection()
        Case "Restore"
            RestoreSelection()
    End Select
End Sub

Private Sub SaveSelection()
    Session(selectedNodesKey) = treeList.GetSelectedNodes().Select(Function(node) node.Key)

End Sub
Private Sub RestoreSelection()
    If Session(selectedNodesKey) Is Nothing Then
        Return
    End If
    Dim rowKeys = DirectCast(Session(selectedNodesKey), IEnumerable(Of String))
    Dim [iterator] = treeList.CreateNodeIterator()
    [iterator].Reset()

    Do While [iterator].Current IsNot Nothing
        [iterator].Current.Selected = rowKeys.Contains([iterator].Current.Key)
        [iterator].GetNext()
    Loop
End Sub