Node Checking - Checkboxes and Radio Buttons

  • 5 minutes to read

To select nodes, use the node checking feature, which enables built-in check boxes or radio buttons for tree levels. In bound mode, you can sync node check states with a database field. This document explains this subject in detail.

TreeList-CheckAndRadios.png

TIP

To select nodes by highlighting them, use the Node Selection feature.

The following sections are covered in this topic.

Enable Checkboxes/Radio Buttons

Show check boxes/radio buttons for all nodes

Set the TreeListOptionsView.CheckBoxStyle property to Check or Radio.

TreeList-CheckAndRadio.png

treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Check;
//or
treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Radio;
TIP

Radio buttons are mutually exclusive options. When you check a certain radio button, the TreeList automatically unchecks a previously checked radio button at the same hierarchy level.

The TreeListOptionsView.CheckBoxStyle property specifies default check box display mode for all TreeList nodes. You can override this setting for root nodes and any node's children, as shown below.

Show check boxes/radio buttons only for root nodes

Set the TreeListOptionsView.RootCheckBoxStyle property to Check or Radio. Leave the TreeListOptionsView.CheckBoxStyle property set to Default.

TreeList-CheckAndRadio-OnlyInRoot

treeList1.OptionsView.RootCheckBoxStyle = NodeCheckBoxStyle.Check;
treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Default;
//or
treeList1.OptionsView.RootCheckBoxStyle = NodeCheckBoxStyle.Radio;
treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Default;

Show check boxes/radio buttons for all nodes, except root nodes

Set TreeListOptionsView.CheckBoxStyle to Check/Radio, and set TreeListOptionsView.RootCheckBoxStyle to None.

TreeList-CheckAndRadio-NotInRoot.png

treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Check;
treeList1.OptionsView.RootCheckBoxStyle = NodeCheckBoxStyle.None;
//or
treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Radio;
treeList1.OptionsView.RootCheckBoxStyle = NodeCheckBoxStyle.None;

Show/hide check boxes/radio buttons for a certain node's children

Use a node's TreeListNode.ChildrenCheckBoxStyle property. This property overrides the TreeListOptionsView.CheckBoxStyle setting for the specified node's children.

TreeList-CheckAndRadio-FirstNodeChildren.png

treeList1.OptionsView.CheckBoxStyle = DefaultNodeCheckBoxStyle.Check;
treeList1.OptionsView.RootCheckBoxStyle = NodeCheckBoxStyle.None;
TreeListNode node1 = treeList1.FindNodeByFieldValue("DEPARTMENT", "Sales and Marketing");
node1.ChildrenCheckBoxStyle = DevExpress.XtraTreeList.NodeCheckBoxStyle.Radio;
NOTE

It is not possible to simultaneously display radio buttons and check boxes at the same hierarchy level.

Related API

Indeterminate Check State

Regular check boxes allow an end-user to toggle between the Checked and Unchecked states. If you enable the TreeListOptionsBehavior.AllowIndeterminateCheckState property, then the TreeList nodes will support three check states (Unchecked, Indeterminate and Checked). Clicking a check box sequentially toggles between these states.

treeList-indeterminatestate.gif

Related API

Get Nodes with Checked/Unchecked/Indeterminate States

To retrieve all checked nodes, use the TreeList.GetAllCheckedNodes method.

The following code shows how to retrieve checked nodes using the TreeList.GetAllCheckedNodes method, and modify their values.

List<TreeListNode> list = treeList1.GetAllCheckedNodes();
foreach (TreeListNode node in list) {
    decimal budget = Convert.ToDecimal(node["BUDGET"])*1.1m;
    node["BUDGET"] = budget;
}

You can recursively retrieve nodes that match a certain condition (for instance, unchecked nodes or nodes with the indeterminate state) using a node iterator.

The following example shows how to use a node iterator to retrieve unchecked TreeList nodes.

using DevExpress.XtraTreeList.Nodes.Operations;

GetUncheckedNodesOperation op = new GetUncheckedNodesOperation();
treeList1.NodesIterator.DoOperation(op);
//Get the number of unchecked nodes:
int count = op.TargetNodes.Count;

//The operation class that collects unchecked nodes
class GetUncheckedNodesOperation : TreeListOperation {
    public List<TreeListNode> TargetNodes = new List<TreeListNode>();
    public GetUncheckedNodesOperation() : base() { }
    public override void Execute(TreeListNode node) {
        if (node.CheckState == CheckState.Unchecked)
            TargetNodes.Add(node);
    }
}

Obtain and Set Node Check States. Recursive Checking.

Use the following members to specify node check states in code.

Recursive Checking

To check/uncheck child nodes when an end-user toggles a parent node's check state, use the TreeListOptionsBehavior.AllowRecursiveNodeChecking property.

Example

TreeListNode node1 = treeList1.FindNodeByFieldValue("DEPARTMENT", "Sales and Marketing");
if (node1 != null)
    treeList1.SetNodeCheckState(node1, CheckState.Checked, false);

Sync Check States with Data Source

Use the TreeList.CheckBoxFieldName property to sync node check states with a specific data source field.

If TreeList nodes only support the checked and unchecked states, the bound data source field should be of the Boolean type. If TreeList nodes use three check states, the data source field should be of the Nullable Boolean type.

Perform Custom Actions on Node Checking

Handle the TreeList.BeforeCheckNode and TreeList.AfterCheckNode events.

Custom Paint Check Boxes

You can custom paint check boxes by handling the TreeList.CustomDrawNodeCheckBox event.

Printing/Export

To print/export check boxes, enable the TreeListOptionsPrint.PrintCheckBoxes option.