GanttControl.BeginUpdate() Method

Does not allow the framework to redraw the control until the CancelUpdate or EndUpdate method is called.

Namespace: DevExpress.XtraGantt

Assembly: DevExpress.XtraGantt.v24.2.dll

Declaration

C#

public override void BeginUpdate()

VB.NET

Public Overrides Sub BeginUpdate

Remarks

After BeginUpdate is called, the framework cannot redraw the control on-screen. You can call this method before you make multiple changes at a time (add multiple items to a collection, customize multiple appearance settings, etc.). This prevents the control from being redrawn after each change and improves performance.

When changes are made, call the CancelUpdate or EndUpdate method. These methods allow the framework to redraw the control. The EndUpdate method also forces the framework to redraw the control immediately. To ensure that the CancelUpdate or EndUpdate method is called even if an exception is thrown, use the try…finally statement.

The BeginUpdate method also disables automatic scheduling — dependent tasks are not re-scheduled when a task is changed (see ScheduleMode).

Example

The code below defers all project tasks for one month.

C#

using DevExpress.XtraTreeList.Nodes;
using DevExpress.XtraTreeList.Nodes.Operations;

ganttControl1.BeginUpdate();
try {
    ganttControl1.NodesIterator.DoOperation(new MyOperation());
}
finally {
    ganttControl1.EndUpdate();
}

public class MyOperation : TreeListOperation {
    public override void Execute(TreeListNode node) {
        node.SetValue("StartDate", ((DateTime)node.GetValue("StartDate")).AddMonths(1));
    }
}

VB.NET

Imports DevExpress.XtraTreeList.Nodes
Imports DevExpress.XtraTreeList.Nodes.Operations

ganttControl1.BeginUpdate()
Try
    ganttControl1.NodesIterator.DoOperation(New MyOperation())
Finally
    ganttControl1.EndUpdate()
End Try

Public Class MyOperation
    Inherits TreeListOperation

    Public Overrides Sub Execute(ByVal node As TreeListNode)
        node.SetValue("StartDate", DirectCast(node.GetValue("StartDate"), DateTime).AddMonths(1))
    End Sub
End Class