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DiagramItemInsertedEventArgs.KeyValue Property

Specifies the key value of the inserted item.

Namespace: DevExpress.Web.ASPxDiagram

Assembly: DevExpress.Web.ASPxDiagram.v22.2.dll

NuGet Package: DevExpress.Web


public object KeyValue { get; set; }

Property Value

Type Description

An object that uniquely identifies the item.


The ASPxDiagram control builds a diagram based on the nodes’ and edges’ key values.

When the control binds to a data source, the source assigns the keys for inserted items. The control send a request to the server side to get the assigned keys. In some cases the control can figure out the keys (for instance, for an SQLDataSource or ObjectDataSource objects).

If the ASPxDiagram control can not determine the keys (for instance, for an EntityDataSource object), specify the KeyValue in the EdgeInserted and NodeInserted events.


If an item’s key is not determined, the “The inserted item key is undefined. Use the DiagramItemInsertedEventArgs.KeyValue property to specify the key value for a newly inserted {0}“ exception is thrown.

<dx:ASPxDiagram ID="Diagram" runat="server" Width="100%" Height="600px" Units="In"
    NodeDataSourceID="FlowNodeDataSource" EdgeDataSourceID="FlowEdgeDataSource" 
    OnNodeInserted="Diagram_ItemInserted" OnEdgeInserted="Diagram_ItemInserted" >
    <SettingsAutoLayout Type="Layered" Orientation="Vertical" />
        <Node Key="ID" Type="Type" Width="Width" Height="Height" />
        <Edge Key="ID" FromKey="FromID" ToKey="ToID" Text="Text" />
<ef:EntityDataSource runat="server" ID="FlowNodeDataSource" ContextTypeName="DevExpress.Web.Demos.FlowContextSL" 
  EntitySetName="Nodes" EnableDelete="True" EnableInsert="True" EnableUpdate="True" OnInserted="FlowItemDataSource_Inserted">
<ef:EntityDataSource runat="server" ID="FlowEdgeDataSource" ContextTypeName="DevExpress.Web.Demos.FlowContextSL" 
  EntitySetName="Edges" EnableDelete="True" EnableInsert="True" EnableUpdate="True" OnInserted="FlowItemDataSource_Inserted">
protected void FlowItemDataSource_Inserted(object sender, Microsoft.AspNet.EntityDataSource.EntityDataSourceChangedEventArgs e) {
    if (e.Entity is FlowEntity)
        lastInsertedId = ((FlowEntity)e.Entity).ID;

protected void Diagram_ItemInserted(object sender, DevExpress.Web.ASPxDiagram.DiagramItemInsertedEventArgs e) {
    e.KeyValue = lastInsertedId;
See Also