how to maintain Start end End time after zoomin

[marco del frate]

Good evening

In my application i binded to Viemodel the StartTime and EndTime. if i change them via two datepicker, the GanttControl reflects it properly. If i use a slider for zooming, and i move it, the ActualStarTime and the ActualEndTime times changes but not the Start and End Time. Why? I woluld like to lock the 2 dates even i move on the zoom

Thank You in advance

Best regards

Marco Del Frate

[Vidyalakshmi Mani]

Hi Marco,

Thank you for contacting us. We have reviewed your query.

To help us analyze the behavior further, could you please share the relevant XAML and C# code snippets from your WPF GanttControl application, particularly the sections related to the `StartTime`, `EndTime`, and zooming implementation?

Additionally, kindly provide a video demonstrating the issue. This will help us better understand the scenario and provide you with appropriate guidance.

Regards,

Vidyalakshmi M.

[marco del frate]

Good morning,

please find attached a project that explain the problem. Once i added tasks pressing on "load Full with dates" button, the two DateTimeEdit Named "TE_DataIni" and "TE_DataFine" show the value they are binded to and that are calculated with the routine

 Sub SetDate()
     VM_Main.DataIni = (From TDM In VM_Main.TaskDetails
                        Select TDM.StartDate).Min.AddMonths(-1)
     VM_Main.DataFine = (From TDM In VM_Main.TaskDetails
                         Select TDM.FinishDate).Max.AddMonths(1)
 End Sub

Because tese date are also binded to GanttControl 

StartTime="{Binding DataIni,Mode=TwoWay}" EndTime="{Binding DataFine,Mode=TwoWay}"

i was expecting that the visualization reflects them but this is not the case.

If then i manually change the date via the 2 datetimeedit, now the ganttcontrols reflect crrectly them.

the other problem is that is i move the the slider that is binded to the zoomfactor, the ganttcontrol actualstarttime and actualendtime change (you can see it looking at the ganttchart) but the starttime and endtime remain as befor the zooming, as you can see looking at the 2 datetimeedit

Hope this is clear also without the video because at the moment i can not register it.

Thank You 

Best regards

Attachment: GanttDemoVB_TDM_(2)_5e938652.zip

[Vishal Omprasad]

Hi Marco,

Thank you for your detailed explanation and for sharing the sample project.

As per the current implementation, when the ZoomFactor is changed, the GanttChart internally recalculates the timeline based on the current horizontal scroll offset. During this process, the control updates its ActualStartTime and ActualEndTime, which are used for rendering the visible range.

The StartTime and EndTime values that are provided or updated act as a reference range during zooming, rather than the actual visual range. As a result, while zooming, the control relies on ActualStartTime and ActualEndTime for UI updates, and the bound StartTime and EndTime properties remain unchanged.

We are currently validating this behavior further at our end to explore possible approaches for maintaining the StartTime and EndTime values consistently during zoom operations. We will analyze this in detail and get back to you with our findings and any feasible solutions.

Regards,
Vishal O.

[Vishal Omprasad]

Hi Marco,

We have checked and we are able to replicate the reported scenario “GanttControl resets StartTime and EndTime to initial values when ZoomFactor is changed”, on our end. We have logged issue report for the same. We will fix this issue and will include the fix in our upcoming weekly NuGet release update, which is expected to roll out on June 16, 2026. We appreciate your patience until then.

You can track the status of this report through the following feedback link.

Feedback link: https://www.syncfusion.com/feedback/74248/ganttcontrol-resets-starttime-and-endtime-to-initial-values-when-zoomfactor-is.

Note: The provided feedback link is private, and you need to log in to view this feedback.

Disclaimer: Inclusion of this solution in the weekly release may change due to other factors including but not limited to QA checks and works reprioritization.

Regards,
Vishal O.

[Vidyalakshmi Mani]

Hi Marco,

We are actively working on the reported issue, "GanttControl resets Start time and End time to initial values when ZoomFactor is changed."

To ensure we are addressing the intended behavior, could you please let us know which of the following you expect?

• After zooming with the slider, the start time shown in the Gantt chart changes and the DateTimeEdit should also be updated to reflect that change.

• After zooming with the slider, the start time shown in the Gantt chart should remain the same as the value set in the DateTimeEdit and should not change.

Please confirm which behavior you would like to achieve.

Regards,

Vidyalakshmi M.

[marco del frate]

Good morning,

the behaviour i would like to achieve is the second one:

• After zooming with the slider, the start time shown in the Gantt chart should remain the same as the value set in the DateTimeEdit and should not change.

It should be the same for endtime.

Thank You,

Best regards

[Aarthi Arjunan]

Hi Marco,

Thank you for explaining the expected behavior. We will make sure to include this in the fix. The update is planned for our weekly release on June 16.

We appreciate your patience and will let you know once the release is available.

Regards,

Aarthi A.

[Vishal Omprasad]

Hi Marco,

We have fixed the reported scenario “GanttControl resets StartTime and EndTime to initial values when ZoomFactor is changed” on our end. Currently, the issue fix is in the testing phase. Once the automation is ensured, we will include the issue fix in our upcoming weekly NuGet release update on June 30, 2026. We will let you know once the NuGet release is rolled-out and appreciate your patience until then.

Disclaimer: Inclusion of this solution in the weekly release may change due to other factors including but not limited to QA checks and works reprioritization.

Regards,
Vishal O.

[marco del frate]

Good morning, 

to be honest, is quite disappointing that the day You stated the fix would be available, and already waited for 3 weeks, you add 2 weeks more...

Anyway... i'll wait..

Thank You

Best regards

[Vishal Omprasad]

Hi Marco,

We understand your concern regarding the delay and appreciate your patience. We have now prioritized this fix, and it is planned to be included in the June 23, 2026 weekly NuGet release.

Thank you for your continued patience, and we will keep you informed once the release is available.

Regards,
Vishal O.

[Vishal Omprasad]

Hi Marco,

We have fixed the reported scenario “GanttControl resets StartTime and EndTime to initial values when ZoomFactor is changed” from our end and included the issue fix in our latest weekly NuGet release update version 33.2.15, which is available for download at nuget.org.

Root-cause: When the zoom factor is dynamically changed, the start time is recalculated relative to the project’s start date.

We thank you for your support and appreciate your patience in waiting for this release. Please get in touch with us if you require any further assistance.

Regards,
Vishal O.

[marco del frate]

Good morning,

I checked the update and now it works as I requested.

Thank You very much for Your support

Best regards

Marco Del Frate

[Vishal Omprasad]

Hi Marco,

Thank you for your confirmation. We are glad the issue is resolved!

Regards,

Vishal.