Completed
Last Updated: 14 Dec 2017 13:38 by ADMIN
To reproduce: click (mouse down) on a task but then release the mouse button off the task. It then stays selected even when I click on other tasks. You can repeat this over and over and end up with every task as "selected" as shown in the video.

Workaround:

 AddHandler Me.RadGanttView1.GraphicalViewItemFormatting, AddressOf GraphicalViewItemFormatting

Private Sub GraphicalViewItemFormatting(sender As Object, e As GanttViewGraphicalViewItemFormattingEventArgs)
    Dim taskItem As GanttViewTaskItemElement = TryCast(e.ItemElement, GanttViewTaskItemElement)
    If taskItem IsNot Nothing AndAlso taskItem.TaskElement.VisualState.Contains(".MouseDown") AndAlso Not taskItem.Selected Then
        taskItem.TaskElement.IsMouseDown = False
    End If
End Sub
Approved
Last Updated: 04 Jan 2017 09:32 by ADMIN
ADMIN
Created by: Dess | Tech Support Engineer, Sr.
Comments: 2
Category: GanttView
Type: Bug Report
2
To reproduce:

public Form1()
{
    InitializeComponent();

    DataTable tasks = new DataTable("Tasks");
    tasks.Columns.Add("Id", typeof(int));
    tasks.Columns.Add("ParentId", typeof(int));
    tasks.Columns.Add("Title", typeof(string));
    tasks.Columns.Add("Start", typeof(DateTime));
    tasks.Columns.Add("End", typeof(DateTime));
    tasks.Columns.Add("Progress", typeof(decimal));
    DataTable links = new DataTable("Links");
    links.Columns.Add("StartId", typeof(int));
    links.Columns.Add("EndId", typeof(int));
    links.Columns.Add("LinkType", typeof(int));
    DataSet data = new DataSet();
    data.Tables.Add(tasks);
    data.Tables.Add(links);

    Random rand = new Random();
    int cnt = 3000;
    int cnt2 = 6000;
    for (int i = 1; i < cnt; i++)
    {
        tasks.Rows.Add(i, 0, "Summary task title", DateTime.Now.AddDays(i), DateTime.Now.AddDays(i + 5), 30m);
    }

    for (int i = cnt; i < cnt2; i++)
    {
        tasks.Rows.Add(i, rand.Next(1, cnt), "First child task title", new DateTime(2010, 10, 10), new DateTime(2010, 10, 12), 10);  
    }
    for (int i = 0; i < 2000; i++)
    {
        links.Rows.Add(rand.Next(cnt, cnt2), rand.Next(1, cnt), 1);
    } 
    
    
    this.radGanttView1.GanttViewElement.TaskDataMember = "Tasks";
    this.radGanttView1.GanttViewElement.ChildMember = "Id";
    this.radGanttView1.GanttViewElement.ParentMember = "ParentId";
    this.radGanttView1.GanttViewElement.TitleMember = "Title";
    this.radGanttView1.GanttViewElement.StartMember = "Start"; 
    this.radGanttView1.GanttViewElement.EndMember = "End";
    this.radGanttView1.GanttViewElement.ProgressMember = "Progress";
    this.radGanttView1.GanttViewElement.LinkDataMember = "Links";
    this.radGanttView1.GanttViewElement.LinkStartMember = "StartId";
    this.radGanttView1.GanttViewElement.LinkEndMember = "EndId";
    this.radGanttView1.GanttViewElement.LinkTypeMember = "LinkType";
    this.radGanttView1.GanttViewElement.DataSource = data;
    this.radGanttView1.Columns.Add("Start");
    this.radGanttView1.Columns.Add("End");
}

private void radButton1_Click(object sender, EventArgs e)
{
    this.radGanttView1.PrintPreview();
}

Approved
Last Updated: 30 Mar 2018 13:09 by ADMIN
How to reproduce: 
  this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineRange = Telerik.WinControls.UI.TimeRange.DayQuarterHours;
  this.radGanttView1.GanttViewElement.GraphicalViewElement.AutomaticTimelineTimeRange = true;
  this.radGanttView1.GanttViewElement.GraphicalViewElement.OnePixelTime = new TimeSpan(0, 0, 15);

Workaround: at the moment the Gantt control does not support an automatic timeline range for day quarter hours. The TimeRange.DayQuarterHours is similar to the half days and they should be handled the same way when in automatic timeline. If possible TimeRange.DayHalfHours 
this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineRange = Telerik.WinControls.UI.TimeRange.DayHalfHours;
Completed
Last Updated: 25 Jun 2018 13:06 by Viktor
To reproduce:
1) Open the Demo application >> Settings example.
2) Select a task and activate the editor for it.
3) Delete the task by clicking the button above.

It may be necessary to repeat the steps several times. The error is not reproduced immediately. 
Approved
Last Updated: 14 Aug 2017 11:53 by ADMIN
ADMIN
Created by: Dess | Tech Support Engineer, Sr.
Comments: 0
Category: GanttView
Type: Bug Report
1
To reproduce: please refer to the attached sample project. Try to edit the title for one of the child tasks in the grid and click the 

Workaround:

private void radGanttView1_ItemChanged(object sender, Telerik.WinControls.UI.GanttViewItemChangedEventArgs e)
{
    IEditableObject editebleObejct = e.Item.DataBoundItem as IEditableObject;
    if (editebleObejct != null)
    {
         editebleObejct.EndEdit();
    }
}
Completed
Last Updated: 27 Apr 2018 15:45 by Dimitar
Workaround: handle the RadGanttView.GraphicalViewItemFormatting event:

    Private Sub GraphicalViewItemFormatting(sender As Object, e As GanttViewGraphicalViewItemFormattingEventArgs)
        Dim taskItem As GanttViewTaskItemElement = TryCast(e.ItemElement, GanttViewTaskItemElement)
        If taskItem IsNot Nothing Then
            taskItem.LeftLinkHandleElement.Opacity = 0
            taskItem.RightLinkHandleElement.Opacity = 0
        End If 
    End Sub
Completed
Last Updated: 19 Mar 2018 14:03 by Dimitar
To reproduce:

        public RadForm1()
        {
            InitializeComponent();

            DataSet ds = new DataSet();
            DataTable dt = new DataTable();
            dt.TableName = "Tasks";
            dt.Columns.Add("Id");
            dt.Columns.Add("ParentID");
            dt.Columns.Add("Title");
            dt.Columns.Add("Start", typeof(DateTime));          
            dt.Columns.Add("End", typeof(DateTime));
            dt.Rows.Add("1", "", "Item1", new DateTime(2018,03,16), new DateTime(2018,03,20));
            dt.Rows.Add("2", "1", "child", new DateTime(2018,03,16), new DateTime(2018,03,17));
            dt.Rows.Add("3", "", "Item2", new DateTime(2018,03,16), new DateTime(2018,03,20));
            ds.Tables.Add(dt);

            this.radGanttView1.GanttViewElement.TaskDataMember = "Tasks";
            this.radGanttView1.GanttViewElement.ChildMember = "Id";
            this.radGanttView1.GanttViewElement.ParentMember = "ParentId";
            this.radGanttView1.GanttViewElement.TitleMember = "Title";
            this.radGanttView1.GanttViewElement.StartMember = "Start";
            this.radGanttView1.GanttViewElement.EndMember = "End";
            this.radGanttView1.GanttViewElement.DataSource = ds;
            this.radGanttView1.Columns.Add("Start");
            this.radGanttView1.Columns.Add("End");            
            this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineStart = new DateTime(2018,03,10);
            this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineEnd = new DateTime(2018,03,31);
            //"child" item is readonly
            radGanttView1.Items[0].ReadOnly = true; 
        }

Workaround:

        public class CustomBaseGanttViewBehavior : BaseGanttViewBehavior
        {
            protected override void ProcessMouseDownOnTaskElement(GanttGraphicalViewBaseTaskElement element, MouseEventArgs e)
            {
                GanttGraphicalViewBaseItemElement taskItem = element.Parent as GanttGraphicalViewBaseItemElement;
                
                if (e.Button == MouseButtons.Left && !taskItem.Data.ReadOnly)
                {
                    base.ProcessMouseDownOnTaskElement(element, e);
                }
            }
        }
Completed
Last Updated: 26 Mar 2018 14:19 by Dimitar
To reproduce: populate RadGanttView with data and hide some of the columns in a button's Click event: 

    Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
        Me.RadGanttView1.GanttViewElement.Columns(0).Visible = False
    End Sub

The column is not hidden until you move the splitter.

Workaround:

    Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
        Me.RadGanttView1.GanttViewElement.Columns(0).Visible = False

        Me.RadGanttView1.GanttViewElement.InvalidateMeasure(True)
        Me.RadGanttView1.GanttViewElement.UpdateLayout()
    End Sub
Completed
Last Updated: 27 Apr 2018 15:53 by Dimitar
To reproduce: have a look at the attached gif file and sample project.

Workaround:

            this.radGanttView1.CursorChanged += radGanttView1_CursorChanged;
            this.radGanttView1.MouseMove += radGanttView1_MouseMove;

        private void radGanttView1_MouseMove(object sender, MouseEventArgs e)
        {
            GanttViewGraphicalViewElement view = this.radGanttView1.ElementTree.GetElementAtPoint(e.Location).FindAncestor<GanttViewGraphicalViewElement>();
            Console.WriteLine(this.radGanttView1.ElementTree.GetElementAtPoint(e.Location));
            if (view != null)
                isOverGraphicalView = true;
            else
                isOverGraphicalView = false;
        }

        bool isOverGraphicalView = false;

        private void radGanttView1_CursorChanged(object sender, EventArgs e)
        {
            if (isOverGraphicalView)
            {
                this.radGanttView1.CursorChanged -= radGanttView1_CursorChanged;
                this.radGanttView1.Cursor = Cursors.Default;
                this.radGanttView1.CursorChanged += radGanttView1_CursorChanged;
            }
        }
Completed
Last Updated: 15 Jun 2018 13:22 by Dimitar
To reproduce:
- Set the range to lest than one day.
- Set the TimelineRange to DayHalfHours

Workaround: 
Make sure that the range is at least one day. 
Approved
Last Updated: 04 Jul 2018 11:44 by ADMIN
ADMIN
Created by: Dess | Tech Support Engineer, Sr.
Comments: 0
Category: GanttView
Type: Bug Report
1
To reproduce: run the sample project and scroll to the end of the view. You will notice that the tasks are not properly aligned. You can increase the GraphicalViewElement.OnePixelTime in order to make the alignment even worse.

Workaround: Adjust the GraphicalViewElement.OnePixelTime in order to obtain the correct alignment.
Completed
Last Updated: 13 Aug 2018 08:13 by Dimitar
To reproduce: run the sample project and try to move a task.

Workaround:

 Timer timer = new Timer();

        private void DragDropService_Stopped(object sender, EventArgs e)
        {
            timer = new Timer();
            timer.Interval = 300;
            timer.Tick += timer_Tick;
            
        }

        private void timer_Tick(object sender, EventArgs e)
        {
            timer.Stop();
            data.Tables["Tasks"].Clear();
        }

Workaround 2:

        private void radGanttView1_ItemElementCreating(object sender, Telerik.WinControls.UI.GanttViewItemElementCreatingEventArgs e)
        {
            if (e.Item.Items.Count == 0 && e.ViewElement is GanttViewGraphicalViewElement)
            {
                e.ItemElement = new MyGanttViewTaskItemElement(e.ViewElement as GanttViewGraphicalViewElement); 
            }
        }

        public class MyGanttViewTaskItemElement : GanttViewTaskItemElement
        {
            public MyGanttViewTaskItemElement(GanttViewGraphicalViewElement ganttViewBaseViewElement) : base(ganttViewBaseViewElement)
            {
            }
            
            protected override Type ThemeEffectiveType
            {
                get
                {
                    return typeof(GanttViewTaskItemElement);
                }
            }

            public override void Detach()
            {
                var obj = this.Data;
                this.Data.SuspendPropertyNotifications();
                base.Detach();
                obj.ResumePropertyNotifications(); 
            }

            public override void Synchronize()
            {
                DataSet ds = this.Data.GanttViewElement.DataSource as DataSet;
                if (ds != null && this.Data != null)
                {
                    DataRowView rowView = this.Data.DataBoundItem as DataRowView;
                    if (rowView != null && !RowExists(rowView.Row))//!ds.Tables[0].Rows.Contains(rowView.Row))
                    {
                        return;
                    }
                }
                base.Synchronize();
            }

            private bool RowExists(DataRow dataRow)
            {
                DataSet ds = this.Data.GanttViewElement.DataSource as DataSet;
                bool res = false;
                foreach (DataRow r in ds.Tables[0].Rows)
                {
                    if (r.Equals(dataRow))
                    {
                        return true;
                    }
                }
                return res;
            }
        }
Completed
Last Updated: 05 Nov 2018 14:44 by Dimitar
ADMIN
Created by: Dess | Tech Support Engineer, Sr.
Comments: 0
Category: GanttView
Type: Bug Report
1
To reproduce: please run the sample project and follow the steps illustrated in the attached gif file. This shows how I’m attempting to add children to a root task. Upon adding a child task I am unable to scroll down to see the rest of the pre-existent root tasks until I first collapse and expand any visible root or child task.

Workaround:

        public RadForm2()
        {
            InitializeComponent();

            this.radGanttView1.ItemAdded += radGanttView1_ItemAdded;  
        }
       
        private void radGanttView1_ItemAdded(object sender, Telerik.WinControls.UI.GanttViewItemAddedEventArgs e)
        {
            item = e.Item;
        }

        GanttViewDataItem item;
        
        private void radButton1_Click(object sender, EventArgs e)
        {
            this.radGanttView1.GanttViewElement.InvalidateMeasure(true);
            this.radGanttView1.GanttViewElement.UpdateLayout();

            this.radGanttView1.GanttViewElement.GraphicalViewElement.Scroller.ScrollToItem(item);
        }
Completed
Last Updated: 06 Feb 2019 12:38 by ADMIN
Created by: Valeriane
Comments: 4
Category: GanttView
Type: Bug Report
1

Hey,

 

We have a problem with the GanttViewTimeLineContainer as you see in the screeshot  : gantt_print2.png

When we are in TimeLineRange = TimeRange.Year and we print the gantt, we have a problem with the appearence of GanttViewTimeLineContainer, we can see the first line with the year (it's ok) but after, the second line we can see a reperition of all month : jfmamjjasond jfmamjjasond jfmamjjasond jfmamjjasond etc etc etc

Can we change the appearence ? Do you have an explanation for this visualization ? 

 

Thank you,

Regards,

Valériane E.

Completed
Last Updated: 17 Jun 2019 14:10 by ADMIN
Release R2 2019 SP1
Created by: Karsten
Comments: 3
Category: GanttView
Type: Bug Report
1

Hi,

why is the datatype of the ChildMember/ParentMember item limited to Int32? This is a problem when displaying tasks or events from tables with string or UUID idents. It would be a more flexible control if the type could be any type. Should not be a big deal to change this or is it?

Thank you und kind regards

Karsten

Completed
Last Updated: 01 Jul 2019 14:38 by ADMIN
Release R3 2019 (LIB 2019.2.708)

The latest release of WinForms causes a fatal exception when adding an item to a BindingList that is used in a RadGridView and a RadGanttView.

The first time an item is added there is not issue.

The second time an item is added, the following exception occurs.

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.WinControls.UI.GanttViewBindingProvider.GanttTaskList.IndexOf(Object key)
   at Telerik.WinControls.UI.GanttViewBindingProvider.GanttTaskList.get_Item(Object key)
   at Telerik.WinControls.UI.GanttViewBindingProvider.AddTaskByCM(CurrencyManager cm, Int32 index)
   at System.ComponentModel.ListChangedEventHandler.Invoke(Object sender, ListChangedEventArgs e)
   at System.Windows.Forms.CurrencyManager.OnListChanged(ListChangedEventArgs e)
   at System.Windows.Forms.CurrencyManager.List_ListChanged(Object sender, ListChangedEventArgs e)
   at System.ComponentModel.BindingList`1.OnListChanged(ListChangedEventArgs e)
   at System.ComponentModel.BindingList`1.FireListChanged(ListChangedType type, Int32 index)
   at MissileWarningThreatPlanner.EventWindow.EventList.GenMissileEventWorker_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e) in C:\Shape Source\VS\MissileWarningThreatPlanner - VS2010\MissileWarningThreatPlanner\EventWindow\EventList.cs:line 5329
   at System.ComponentModel.BackgroundWorker.OnRunWorkerCompleted(RunWorkerCompletedEventArgs e)

This is code that has not been modified for quite some time.  There has been no issue until the latest release.

I do not have time to try to create a simple example to try to reproduce the error at this time.  I will if possible.

For now, we are forced to revert to a previous version.

 

Ken...

Completed
Last Updated: 20 Aug 2019 11:34 by ADMIN
Release R3 2019

Please refer to the attached sample project and run it. Select a random item and press the button. You will obtain the error. If no selection is available, the item is removed as expected. 

Workaround: use Begin/EndUpdate block while deleting a record from the DataTable:

        Me.RadGanttView1.BeginUpdate()
        _dataset.Tables("Tasks").Rows.RemoveAt(2)
        Me.RadGanttView1.EndUpdate()

Completed
Last Updated: 15 Aug 2019 13:54 by ADMIN
Release R3 2019 (LIB 2019.2.819)

Please run the attached sample project. Select one of the child tasks and click the button. The new task is expected to be inserted at the selected item's position. However, it is appended at the bottom as it is demonstrated in the gif file.

Workaround: rebind RadGanttView after inserting a new row to the DataTable: 

    Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
        Try
            If Me.RadGanttView1.SelectedItem IsNot Nothing Then
                Dim i_rowIndex As Int32 = _dataset.Tables("Tasks").Rows.IndexOf(Me.RadGanttView1.SelectedItem.DataBoundItem.Row)
                Dim i_datarow As DataRow = _dataset.Tables("Tasks").NewRow
                Dim i_startDate As Date = New Date(Today.Year, Today.Month, Today.Day, 8, 0, 0)
                i_datarow("ID") = 3001
                i_datarow("ParentID") = _projektID
                i_datarow("Bezeichnung") = "inserted Aufgabe"
                i_datarow("Start") = i_startDate.AddHours(6 * 5)
                i_datarow("Ende") = i_startDate.AddHours(6 + 100)
                _dataset.Tables("Tasks").Rows.InsertAt(i_datarow, i_rowIndex)
                Me.RadGanttView1.DataSource = Nothing
                With Me.RadGanttView1.GanttViewElement
                    .TaskDataMember = "Tasks"
                    .ChildMember = "ID"
                    .ParentMember = "ParentID"
                    .TitleMember = "Bezeichnung"
                    .StartMember = "Start"
                    .EndMember = "Ende"
                End With
                Me.RadGanttView1.DataSource = _dataset
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

 

Completed
Last Updated: 16 Aug 2016 12:27 by ADMIN
Dim data As New DataSet()
Dim tasks As New DataTable("Tasks")
Dim links As New DataTable("Links")
Sub New()
    InitializeComponent()

    tasks.Columns.Add("Id", GetType(Integer))
    tasks.Columns.Add("ParentId", GetType(Integer))
    tasks.Columns.Add("Title", GetType(String))
    tasks.Columns.Add("Start", GetType(DateTime))
    tasks.Columns.Add("End", GetType(DateTime))
    tasks.Columns.Add("Progress", GetType(Decimal))

    links.Columns.Add("StartId", GetType(Integer))
    links.Columns.Add("EndId", GetType(Integer))
    links.Columns.Add("LinkType", GetType(Integer))

    data.Tables.Add(tasks)
    data.Tables.Add(links)
    tasks.Rows.Add(1, 0, "1. Summary task title", New DateTime(2010, 10, 10), New DateTime(2010, 10, 15), 30D)
    tasks.Rows.Add(2, 1, "1.1 Task", New DateTime(2010, 10, 10), New DateTime(2010, 10, 12), 10)
    tasks.Rows.Add(3, 1, "1.2 Task", New DateTime(2010, 10, 12), New DateTime(2010, 10, 15), 20D)
    tasks.Rows.Add(4, 1, "1.3 Task", New DateTime(2010, 10, 10), New DateTime(2010, 10, 11), 20D)
    tasks.Rows.Add(5, 1, "Milestone", New DateTime(2010, 10, 15), New DateTime(2010, 10, 15), 0D)
    tasks.Rows.Add(6, 0, "2. Summary task title", New DateTime(2010, 10, 10), New DateTime(2010, 10, 13), 30D)
    tasks.Rows.Add(7, 6, "2.1 Task", New DateTime(2010, 10, 10), New DateTime(2010, 10, 11), 10)
    links.Rows.Add(2, 3, 1)
    links.Rows.Add(3, 5, 1)

    Bind()
    Me.RadGanttView1.Columns.Add("Start")
    Me.RadGanttView1.Columns.Add("End")
    Me.RadGanttView1.Columns.Add("Id")
    Me.RadGanttView1.Columns.Add("ParentId")

    Me.RadGanttView1.GanttViewElement.GraphicalViewElement.TimelineStart = New DateTime(2010, 10, 9)
End Sub

Private Sub Bind()
    Me.RadGanttView1.GanttViewElement.DataSource = Nothing
    Me.RadGanttView1.GanttViewElement.TaskDataMember = "Tasks"
    Me.RadGanttView1.GanttViewElement.ChildMember = "Id"
    Me.RadGanttView1.GanttViewElement.ParentMember = "ParentId"
    Me.RadGanttView1.GanttViewElement.TitleMember = "Title"
    Me.RadGanttView1.GanttViewElement.StartMember = "Start"
    Me.RadGanttView1.GanttViewElement.EndMember = "End"
    Me.RadGanttView1.GanttViewElement.ProgressMember = "Progress"
    Me.RadGanttView1.GanttViewElement.LinkDataMember = "Links"
    Me.RadGanttView1.GanttViewElement.LinkStartMember = "StartId"
    Me.RadGanttView1.GanttViewElement.LinkEndMember = "EndId"
    Me.RadGanttView1.GanttViewElement.LinkTypeMember = "LinkType"
    Me.RadGanttView1.GanttViewElement.DataSource = data
End Sub

Private Sub RadButtonClick(sender As Object, e As EventArgs) Handles RadButton2.Click
    tasks(3)("ParentId") = 6
    Bind()
End Sub

Workaround: rebind the ganttview after changing the parent.
Completed
Last Updated: 01 Jun 2015 10:34 by ADMIN
To reproduce:
public RadForm1()
{
    InitializeComponent();
    DataTable tasks = new DataTable("Tasks");
    tasks.Columns.Add("Id", typeof(int));
    tasks.Columns.Add("ParentId", typeof(int));
    tasks.Columns.Add("Title", typeof(string));
    tasks.Columns.Add("Start", typeof(DateTime));
    tasks.Columns.Add("End", typeof(DateTime));
    tasks.Columns.Add("Progress", typeof(decimal));

    DataTable links = new DataTable("Links");
    links.Columns.Add("StartId", typeof(int));
    links.Columns.Add("EndId", typeof(int));
    links.Columns.Add("LinkType", typeof(int));

    tasks.Rows.Add(1, 0, "Summary task title", new DateTime(2010, 10, 8), new DateTime(2010, 10, 18), 30m);
    tasks.Rows.Add(2, 1, "First child task title", new DateTime(2010, 10, 10), new DateTime(2010, 10, 12), 10);
    tasks.Rows.Add(3, 1, "Second child task title", new DateTime(2010, 10, 12), new DateTime(2010, 10, 15), 20m);
    tasks.Rows.Add(4, 1, "Milestone", new DateTime(2010, 10, 15), new DateTime(2010, 10, 15), 0m);

    links.Rows.Add(2, 3, 1);
    links.Rows.Add(3, 4, 1);

    DataSet data = new DataSet();
    data.Tables.Add(tasks.Copy());
    data.Tables.Add(links);

    this.radGridView1.DataSource = tasks;
    radGridView1.BestFitColumns();

    this.radGanttView1.CreateDataItem += radGanttView1_CreateDataItem;
    this.radGanttView1.AllowSummaryEditing = true;
    this.radGanttView1.GanttViewElement.TaskDataMember = "Tasks";
    this.radGanttView1.GanttViewElement.ChildMember = "Id";
    this.radGanttView1.GanttViewElement.ParentMember = "ParentId";
    this.radGanttView1.GanttViewElement.TitleMember = "Title";
    this.radGanttView1.GanttViewElement.StartMember = "Start";
    this.radGanttView1.GanttViewElement.EndMember = "End";
    this.radGanttView1.GanttViewElement.ProgressMember = "Progress";
    this.radGanttView1.GanttViewElement.LinkDataMember = "Links";
    this.radGanttView1.GanttViewElement.LinkStartMember = "StartId";
    this.radGanttView1.GanttViewElement.LinkEndMember = "EndId";
    this.radGanttView1.GanttViewElement.LinkTypeMember = "LinkType";

    this.radGanttView1.GanttViewElement.DataSource = data;

    this.radGanttView1.Columns.Add("Start");
    this.radGanttView1.Columns.Add("End");
    this.radGanttView1.Columns.Add("Progress");

    this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineStart = new DateTime(2010, 10, 7);
    this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineEnd = new DateTime(2010, 12, 10);
}
You will notice that the start and end of the summary task are changed in the gantt view.

Workaround:
void radGanttView1_CreateDataItem(object sender, CreateGanttDataItemEventArgs e)
{
    e.Item = new MyGanttViewDataItem();
}

public class MyGanttViewDataItem : GanttViewDataItem
{
    protected override void OnChildAdded(GanttViewDataItem child)
    {
        if (this.Parent != null && !this.GanttViewElement.AllowSummaryEditing)
        {
            base.OnChildAdded(child);
        }
    }

    protected override void OnChildRemoved(GanttViewDataItem child)
    {
        if (this.Parent != null && !this.GanttViewElement.AllowSummaryEditing)
        {
            base.OnChildRemoved(child);
        }
    }
}

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