InsertTask(
    data: any
): void

<dx:ASPxGantt ID="Gantt" runat="server" ClientInstanceName="clientGantt" >
    //...
</dx:ASPxGantt>

// Inserts a new task with the specified subject at the end of the other tasks.
clientGantt.InsertTask({ Subject: "Test task"});

// Inserts a child task with the specified subject as a child of the task with ID = 2 
clientGantt.InsertTask({ ParentID: 2, Subject: "Test task"});