Currently, there is LinkChanged event.

It would be useful if there is also LinkChanged event that allows to be canceled upon some condition.

Please use the following code snippet:

    public partial class Form1 : Form
    {
        public class VM
        {
            public string Text
            {
                get; set;
            }
            public DateTime Start
            {
                get; set;
            }
            public DateTime End
            {
                get; set;
            }
        }

        public Form1()
        {
            InitializeComponent();

            var ViewModel = new VM[]
            {
                new VM()
                {
                    Text = "CrashTest",
                    Start = new DateTime(2021, 11, 3, 10, 0, 0),
                    End = new DateTime( 2021, 11, 3, 23, 0, 0 )  //crash
                    //End = new DateTime( 2021, 11, 3, 22, 0, 0 )  //No crash
                },
            };

            radGanttView1.GanttViewElement.GraphicalViewElement.OnePixelTime = new TimeSpan( 0, 1, 0 );
            radGanttView1.GanttViewElement.GraphicalViewElement.TimelineStart = ViewModel.Min( T => T.Start );
            radGanttView1.GanttViewElement.GraphicalViewElement.TimelineEnd = ViewModel.Max( T => T.End );
            radGanttView1.GanttViewElement.GraphicalViewElement.TimelineRange = TimeRange.Day;

            radGanttView1.GanttViewElement.ChildMember = "Text";
            radGanttView1.GanttViewElement.TitleMember = "Text";
            radGanttView1.GanttViewElement.StartMember = "Start";
            radGanttView1.GanttViewElement.EndMember = "End";

            radGanttView1.DataSource = ViewModel;
        }
    }

Currently, the possible solution that I can suggest is to increase the view's end with 1 hour:

  radGanttView1.GanttViewElement.GraphicalViewElement.TimelineEnd = ViewModel.Max( T => T.End.AddHours(1));

Please refer to the attached gif file.

Please use the following code snippet. Activate the editor for a cell and click another cell:

private DataSet weddingPlan;
public DataSet WeddingPlan {
    get 
    { 
        if(weddingPlan == null)
        {
            weddingPlan = new DataSet();
            using (StreamReader rdr = new StreamReader("TelerikWeddingPlanner.xml"))
            {
                weddingPlan.ReadXml(rdr);
            }
        }

        return weddingPlan;
    }
}

public Form1()
{
    InitializeComponent();

    // Events
    this.radGanttView1.GanttViewElement.EditorRequired += GanttViewElement_EditorRequired;
    this.radGanttView1.GanttViewElement.EditorInitialized += GanttViewElement_EditorInitialized;
    this.radGanttView1.GanttViewElement.ItemValidating += GanttViewElement_ItemValidating;
    this.radGanttView1.GanttViewElement.ItemValidated += GanttViewElement_ItemValidated;
    this.radGanttView1.GanttViewElement.ItemEdited += GanttViewElement_ItemEdited;
}

private void GanttViewElement_DoubleClick(object sender, EventArgs e)
{
    Debug.WriteLine("GanttViewElement_DoubleClick");
}

private void GanttViewElement_EditorRequired(object sender, GanttViewEditorRequiredEventArgs e)
{
    Debug.WriteLine("GanttViewElement_EditorRequired");
    
}

private void GanttViewElement_EditorInitialized(object sender, GanttViewItemEditorInitializedEventArgs e)
{
    Debug.WriteLine("GanttViewElement_EditorInitialized");
    
}

private void GanttViewElement_ItemValidated(object sender, GanttViewItemValidatedEventArgs e)
{
    Debug.WriteLine("GanttViewElement_ItemValidated");
    
}

private void GanttViewElement_ItemValidating(object sender, GanttViewItemValidatingEventArgs e)
{
    Debug.WriteLine("GanttViewElement_ItemValidating");
    Debug.WriteLine(e.Column.FieldName);
    e.Cancel = true;
}

private void GanttViewElement_ItemEdited(object sender, GanttViewItemEditedEventArgs e)
{
    Debug.WriteLine("GanttViewElement_ItemEdited");
    
}

private void Form1_Load(object sender, EventArgs e)
{
    this.radGanttView1.DataSource = WeddingPlan;


    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 = "Finish";
    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.Columns.Add(new GanttViewTextViewColumn("Id"));
    this.radGanttView1.GanttViewElement.Columns.Add(new GanttViewTextViewColumn("ParentId"));
    this.radGanttView1.GanttViewElement.Columns.Add(new GanttViewTextViewColumn("Title"));
    this.radGanttView1.GanttViewElement.Columns.Add(new GanttViewTextViewColumn("Start"));
    this.radGanttView1.GanttViewElement.Columns.Add(new GanttViewTextViewColumn("Finish"));

    this.radGanttView1.GanttViewElement.Columns[0].Visible = false;
    this.radGanttView1.GanttViewElement.Columns[1].Visible = false;
    this.radGanttView1.GanttViewElement.Columns[2].Width = 350;
    this.radGanttView1.GanttViewElement.Columns[3].Width = 120;
    this.radGanttView1.GanttViewElement.Columns[4].Width = 120;

    this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineRange = TimeRange.Month;
    this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineStart = new DateTime(2006, 8, 21);
    this.radGanttView1.GanttViewElement.GraphicalViewElement.TimelineEnd = new DateTime(2007, 4, 3);

}

private void radGanttView1_ItemChildIdNeeded(object sender, GanttViewItemChildIdNeededEventArgs e)
{
    int max = int.MinValue;
    foreach (DataRow row in (this.radGanttView1.DataSource as DataSet).Tables[0].Rows)
    {
        if (int.Parse(row[0].ToString()) > max)
        {
            max = int.Parse(row[0].ToString());
        }
    }
    e.ChildId = ++max;
}

Hey !

I need to know if you plan the development of a new function :

When you are in the list of your tasks, i want to navigate with the keyboard. 

Im' Here :

And when i navigate in the list with the keyboard, i need to see the last column on the same task :

The focus is good but the horizontal scrollBar is on the same place and we can't the the all value of the cell.

Can we plan the improvment ? Or do you have a clean solution?

If you need more informations,

don't hesitate to contact me

Regards,

Valériane 

It would be useful if the control takes advantage of the RadSpreadProcessing, RadPdfProcessing and RadWordsProcessing. This will allow developers to easily export the control's contents to the desired format. 

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.

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;

How to reproduce:

1. Run the project 
2. Press the radButton1 
3. Edit description of the first line (Line whose Identifier is TestProject1) 
4. Clicking some other line to end the edit causes the ASSERT to come up 

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();
    }
}

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();
}

To reproduce:

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    'TODO: This line of code loads data into the 'WeddingPlannerDataSet.Tasks' table. You can move, or remove it, as needed.
    Me.TasksTableAdapter.Fill(Me.WeddingPlannerDataSet.Tasks)
    'TODO: This line of code loads data into the 'WeddingPlannerDataSet.Links' table. You can move, or remove it, as needed.
    Me.LinksTableAdapter.Fill(Me.WeddingPlannerDataSet.Links)


    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 = Me.WeddingPlannerDataSet

    Me.RadGanttView1.Columns.Add("Start")
    Me.RadGanttView1.Columns.Add("End")

    Me.RadGanttView1.Ratio = 0.3
    Me.RadGanttView1.GanttViewElement.GraphicalViewElement.TimelineStart = New DateTime(2006, 8, 20)
    Me.RadGanttView1.GanttViewElement.GraphicalViewElement.TimelineEnd = New DateTime(2007, 4, 2)

    AddHandler Me.RadGanttView1.ItemChildIdNeeded, AddressOf ItemChildIdNeeded
    AddHandler Me.RadGanttView1.ItemAdding, AddressOf ItemAdding
    AddHandler Me.RadGanttView1.ItemAdded, AddressOf ItemAdded
End Sub
Dim integerIdCounter As Integer = 200
Private Sub ItemChildIdNeeded(sender As Object, e As Telerik.WinControls.UI.GanttViewItemChildIdNeededEventArgs)
    Me.integerIdCounter += 1
    e.ChildId = Me.integerIdCounter
End Sub

Workaround:
AddHandler Me.RadGanttView1.ContextMenuOpening, AddressOf RadGanttView1_ContextMenuOpening

 Private Sub RadGanttView1_ContextMenuOpening(sender As Object, e As Telerik.WinControls.UI.GanttViewContextMenuOpeningEventArgs)
     Dim item As RadMenuItem = DirectCast(e.Menu.Items(0), RadMenuItem)
     AddHandler item.Items(0).Click, AddressOf ItemClick
 End Sub

 Private Sub ItemClick(sender As Object, e As EventArgs)
     Me.RadGanttView1.GanttViewElement.GraphicalViewElement.Update(Telerik.WinControls.UI.RadGanttViewElement.UpdateActions.ExpandedChanged)
 End Sub

Currently when you set the TimelineRange property to TimeRange.Week displays two elements (the TopElement with weeks and the BottomElement with days). There are cases where users want to display single timeline - only weeks, days, quarters or years independent of the second timeline.  

Workaround: 
 Sub New()

        InitializeComponent()

        Me.SetUpGantt()

        Me.RadGanttView1.GanttViewElement.TextViewElement.Scroller.AllowHiddenScrolling = True

        AddHandler Me.RadGanttView1.MouseUp, AddressOf Me.RadGanttView1_MouseUp
    End Sub

Private Sub RadGanttView1_MouseUp(sender As Object, e As MouseEventArgs)
        Dim location = e.Location

        Dim splitter As GanttViewViewsSplitterElement = TryCast(Me.RadGanttView1.ElementTree.GetElementAtPoint(e.Location), GanttViewViewsSplitterElement)
        If splitter IsNot Nothing Then
            Me.RadGanttView1.GanttViewElement.TextViewElement.Scroller.Scrollbar.Value = Me.RadGanttView1.GanttViewElement.GraphicalViewElement.VScrollBar.Value
        End If
    End Sub

The position of splitter should allow to be fixed while resizing the control. Users want to be able to set the splitter next to the last column of TextViewElement when resizing. 

Please look at the attached screenshot.

Workaround: you can replace the StackLayoutElement used in the GanttViewTimelineItemBottomStackElement with a DockLayoutPanel for example as follows:

Public Class CustomGanttViewTimelineItemElement
Inherits GanttViewTimelineItemElement
    Public Sub New(data As GanttViewTimelineDataItem, graphicalViewElement As GanttViewGraphicalViewElement)
        MyBase.New(data, graphicalViewElement)

    End Sub
    Dim dock As DockLayoutPanel
    Protected Overrides Sub CreateChildElements()
        MyBase.CreateChildElements()
        dock = New DockLayoutPanel()
        dock.StretchHorizontally = True
        dock.LastChildFill = False
        Me.Children.RemoveAt(Me.Children.Count - 1)
        Me.Children.Add(dock)
    End Sub

    Protected Overrides Sub CalculateItems()
        Me.SuspendLayout()

        Dim cellInfo As GanttTimelineCellsInfo = Me.GraphicalViewElement.TimelineBehavior.GetTimelineCellInfoForItem(Me.Data, Me.GraphicalViewElement.TimelineRange)

        While Me.dock.Children.Count > cellInfo.NumberOfcells
            Me.dock.Children.RemoveAt(0)
        End While

        While Me.dock.Children.Count < cellInfo.NumberOfcells
            Dim element As LightVisualElement = Me.GraphicalViewElement.TimelineBehavior.CreateElement()
            Me.dock.Children.Add(element)
        End While

        Me.TopElement.Text = Me.GraphicalViewElement.TimelineBehavior.GetTimelineTopElementText(Me.Data)

        For i As Integer = 0 To Me.dock.Children.Count - 1
            DirectCast(Me.dock.Children(i), LightVisualElement).Text = Me.GraphicalViewElement.TimelineBehavior.GetTimelineBottomElementText(Me.Data, i + cellInfo.StartIndex)
        Next

        Me.ResumeLayout(True)
    End Sub

    Protected Overrides Function MeasureOverride(availableSize As SizeF) As SizeF
        Dim clientRect As RectangleF = Me.GetClientRectangle(availableSize)
        Dim width As Single = Me.Data.Width - Me.GraphicalViewElement.TimelineContainer.ItemSpacing + availableSize.Width - clientRect.Width

        Me.TopElement.Measure(New SizeF(width, clientRect.Height / 2.0F))
        Me.dock.Measure(New SizeF(width, clientRect.Height / 2.0F))

        Return New SizeF(width, Me.TopElement.DesiredSize.Height + Me.dock.DesiredSize.Height)
    End Function

    Protected Overrides Function ArrangeOverride(finalSize As SizeF) As SizeF
        Dim clientRect As RectangleF = Me.GetClientRectangle(finalSize)

        Dim topRect As New RectangleF(clientRect.X, clientRect.Y, Me.DesiredSize.Width, clientRect.Height / 2.0F)
        Me.TopElement.Arrange(topRect)
        Dim bottomRect As New RectangleF(clientRect.X, topRect.Bottom, Me.DesiredSize.Width, clientRect.Height - topRect.Height)
        Me.dock.Arrange(bottomRect)

        Return clientRect.Size
    End Function
End Class

Public Class CustomGanttViewTimelineElementProvider
Inherits GanttViewTimelineElementProvider

    Public Sub New(owner As GanttViewGraphicalViewElement)
        MyBase.New(owner)

    End Sub
    Public Overrides Function CreateElement(data As GanttViewTimelineDataItem, context As Object) As IVirtualizedElement(Of GanttViewTimelineDataItem)
        Dim element As GanttViewTimelineItemElement = Me.OnItemElementCreating(data)

        Return New CustomGanttViewTimelineItemElement(data, Owner)
    End Function
End Class