MetaAttributesBreadcrumb.OnBeforeReplaceItem

Syntax

OnBeforeReplaceItem(Sender: Object; Args: IMetaAttributeBreadcrumbReplaceItemEventArgs);

Parameters

Sender. The parameter that returns the component that generated the event.

Args. The parameter that enables the user to determine event parameters.

Description

The OnBeforeReplaceItem event occurs before component elements are replaced.

Comments

One can check replaced elements in this event, using property of the IMetaAttributeBreadcrumbReplaceItemEventArgs.Attribute argument. Set the IBreadcrumbActionItemEventArgs.Allow property to corresponding value to allow or deny replacing of elements.

Example

Executing the example requires a form with the Button1 button and the MetaAttributesBreadcrumb component named MetaAttributesBreadcrumb1. This component is connected to any time series database. The specified procedure is set for MetaAttributesBreadcrumb1 as a handler of the OnBeforeReplaceItem event.

Sub MetaAttributesBreadcrumb1OnBeforeReplaceItem(Sender: Object; Args: IMetaAttributeBreadcrumbReplaceItemEventArgs);
Var
    Item: IMetaAttributeBreadcrumbItem;
Begin
    Item := Args.Item As IMetaAttributeBreadcrumbItem;
    If (Item.MetaAttribute.Id = "DL") And (Args.Attribute = "COUNTRY") Then
        Args.Allow := False;
    End If;
End Sub MetaAttributesBreadcrumb1OnBeforeReplaceItem;

When the event occurs, attribute identifiers are checked. If replaceable element corresponds to an attribute with the DL identifier, and the user tries to replace it by an attribute with the COUNTRY identifier, substitution is denied.