TreeListNodeValidationEventArgs.NodeError Property

Gets or sets the error text displayed within the Error Node.

Namespace: DevExpress.Web.ASPxTreeList

Assembly: DevExpress.Web.ASPxTreeList.v25.1.dll

NuGet Package: DevExpress.Web

Declaration

C#

public string NodeError { get; set; }

VB.NET

Public Property NodeError As String

Property Value

Type	Description
String	A String value that specifies the text displayed within the Error Node.

Remarks

Setting the NodeError property to a not empty string automatically displays the Error Node below the edited node.

Example

This example demonstrates how to check the validity of data entered by end-users into a node. Validation is implemented within the ASPxTreeList.NodeValidating event handler. In this sample, validation fails in the cases listed below:

• the department isn’t specified;
• the budget is negative.

The image below shows the result:

ASPX

<dx:ASPxTreeList ID="ASPxTreeList1" runat="server" AutoGenerateColumns="False"
    DataSourceID="AccessDataSource1"
    KeyFieldName="ID" ParentFieldName="ParentID" OnNodeValidating="ASPxTreeList1_NodeValidating">
    <Columns>
        <dx:TreeListTextColumn FieldName="Department" VisibleIndex="0">
        </dx:TreeListTextColumn>
        <dx:TreeListTextColumn FieldName="Budget" VisibleIndex="1">
        </dx:TreeListTextColumn>
        <dx:TreeListTextColumn FieldName="Location" VisibleIndex="2">
        </dx:TreeListTextColumn>
        <dx:TreeListTextColumn FieldName="Phone" VisibleIndex="3">
        </dx:TreeListTextColumn>
        <dx:TreeListCommandColumn VisibleIndex="4">
            <EditButton Visible="True">
            </EditButton>
        </dx:TreeListCommandColumn>
    </Columns>
</dx:ASPxTreeList>

C#

protected void ASPxTreeList1_NodeValidating(object sender, TreeListNodeValidationEventArgs e) {
    if ((int)e.NewValues["Budget"] < 0)
        e.Errors["Budget"] = "Negative values aren't allowed";
    if (e.NewValues["Department"] == null)
        e.Errors["Department"] = "Required field";
    if (e.Errors.Count != 0)
        e.NodeError = "Node update failed. Please check node values.";
}