Gets/sets a value that is used to store a dataset key or other information.

Syntax

Visual Basic (Declaration)
Public Property DataKey As Object

C#
public object DataKey {get; set;}

Remarks

DataKey is essentially an additional Tag property of a node which can be used for storing key information for relational data. It is intended for use when the Override.ShowExpansionIndicator property of a node is set to CheckOnDisplay.

Example

The following sample code illustrates some of the information available in the BeforeExpand event.

For an overview of how to handle events in Visual Basic or Visual C#, see Event Handlers in Visual Basic and Visual C#. For specific information and code examples illustrating how to consume events in your application, see Consuming Events in the .NET Framework Developer's Guide.

Visual Basic Copy Code

Visual Basic	Copy Code
Imports Infragistics.Win.UltraWinTree Private Sub ultraTree1_BeforeExpand(ByVal sender As Object, ByVal e As Infragistics.Win.UltraWinTree.CancelableNodeEventArgs) Handles ultraTree1.BeforeExpand ' Note: In order to load node collections on demand, set ' the appropriate Override object's 'ShowExpansionIndicator' ' property to 'CheckOnExpand'. Then in this event place ' logic to add the child nodes to the node being expanded ' (e.g. with the e.TreeNode.Nodes's 'Add' or 'AddRange' methods). ' ' In addition to its 'Tag' property the node exposes ' a 'DataKey' property (which is also opaque to the node). ' It is often useful with 'CheckOnDemand' to associate ' some identifier/key of a corresponding row in a dataset. ' ' With 'CheckOnExpand' specified, if this event is called ' and no child nodes are added then the expansion indicator ' will disappear and this event will not fire again. ' ' However, this can be reset by calling the UltraTree's ' 'ResetExpansionIndicator' method to re-show the expansion ' indicator and re-fire this event when the user expands the ' node again. ' ' Refer to the 'UltraTree Load On Demand VB' sample. Dim sb As New System.Text.StringBuilder() sb.Append("Node: ") sb.Append(e.TreeNode.Key) sb.Append(" is about to be expanded.") Debug.WriteLine(sb.ToString()) ' Note : This action can be canceled by the following line of code. 'e.Cancel = True End Sub

    Imports Infragistics.Win.UltraWinTree



    Private Sub ultraTree1_BeforeExpand(ByVal sender As Object, ByVal e As Infragistics.Win.UltraWinTree.CancelableNodeEventArgs) Handles ultraTree1.BeforeExpand



        ' Note: In order to load node collections on demand, set

        ' the appropriate Override object's 'ShowExpansionIndicator'

        ' property to 'CheckOnExpand'. Then in this event place

        ' logic to add the child nodes to the node being expanded

        ' (e.g. with the e.TreeNode.Nodes's 'Add' or 'AddRange' methods).

        '

        ' In addition to its 'Tag' property the node exposes

        ' a 'DataKey' property (which is also opaque to the node).

        ' It is often useful with 'CheckOnDemand' to associate

        ' some identifier/key of a corresponding row in a dataset.

        '

        ' With 'CheckOnExpand' specified, if this event is called

        ' and no child nodes are added then the expansion indicator

        ' will disappear and this event will not fire again.

        '

        ' However, this can be reset by calling the UltraTree's

        ' 'ResetExpansionIndicator' method to re-show the expansion

        ' indicator and re-fire this event when the user expands the

        ' node again.

        '

        ' Refer to the 'UltraTree Load On Demand VB' sample.



        Dim sb As New System.Text.StringBuilder()



        sb.Append("Node: ")

        sb.Append(e.TreeNode.Key)

        sb.Append(" is about to be expanded.")



        Debug.WriteLine(sb.ToString())



        ' Note : This action can be canceled by the following line of code.

        'e.Cancel = True



    End Sub

C# Copy Code

C#	Copy Code
using System.Diagnostics; using Infragistics.Win.UltraWinTree; private void ultraTree1_BeforeExpand(object sender, Infragistics.Win.UltraWinTree.CancelableNodeEventArgs e) { // Note: In order to load node collections on demand, set // the appropriate Override object's 'ShowExpansionIndicator' // property to 'CheckOnExpand'. Then in this event place // logic to add the child nodes to the node being expanded // (e.g. with the e.TreeNode.Nodes's 'Add' or 'AddRange' methods). // // In addition to its 'Tag' property the node exposes // a 'DataKey' property (which is also opaque to the node). // It is often useful with 'CheckOnDemand' to associate // some identifier/key of a corresponding row in a dataset. // // With 'CheckOnExpand' specified, if this event is called // and no child nodes are added then the expansion indicator // will disappear and this event will not fire again. // // However, this can be reset by calling the UltraTree's // 'ResetExpansionIndicator' method to re-show the expansion // indicator and re-fire this event when the user expands the // node again. // // Refer to the 'UltraTree Load On Demand CS' sample. System.Text.StringBuilder sb = new System.Text.StringBuilder(); sb.Append("Node: "); sb.Append(e.TreeNode.Key); sb.Append(" is about to be expanded."); Debug.WriteLine( sb.ToString() ); // Note : This action can be canceled by the following line of code. //e.Cancel = true; }

       using System.Diagnostics;

       using Infragistics.Win.UltraWinTree;



       private void ultraTree1_BeforeExpand(object sender, Infragistics.Win.UltraWinTree.CancelableNodeEventArgs
e)

       {



           // Note: In order to load node collections on demand, set

           // the appropriate Override object's 'ShowExpansionIndicator'

           // property to 'CheckOnExpand'. Then in this event place

           // logic to add the child nodes to the node being expanded

           // (e.g. with the e.TreeNode.Nodes's 'Add' or 'AddRange'
methods).

           //

           // In addition to its 'Tag' property the node exposes

           // a 'DataKey' property (which is also opaque to the node).

           // It is often useful with 'CheckOnDemand' to associate

           // some identifier/key of a corresponding row in a dataset.

           //

           // With 'CheckOnExpand' specified, if this event is called

           // and no child nodes are added then the expansion indicator

           // will disappear and this event will not fire again.

           //

           // However, this can be reset by calling the UltraTree's

           // 'ResetExpansionIndicator' method to re-show the expansion

           // indicator and re-fire this event when the user expands the

           // node again.

           //

           // Refer to the 'UltraTree Load On Demand CS' sample.

           

           System.Text.StringBuilder sb = new System.Text.StringBuilder();



           sb.Append("Node: ");

           sb.Append(e.TreeNode.Key);

           sb.Append(" is about to be expanded.");



           Debug.WriteLine( sb.ToString() );



           // Note : This action can be canceled by the following line of
code.

           //e.Cancel = true;

       

       }

Syntax

Remarks

Example

See Also

Reference

Infragistics2.Win.UltraWinTree.v8.1
DataKey Property
See Also Example