Hi Lukas,
Thanks for using Syncfusion Products.
You can achieve your requirement by setting AllowSelection and ListBoxSelectionMode properties as follows:
Code snippet [C#]:
this.dataGrid.Model.Options.AllowSelection = GridSelectionFlags.Any;
this.dataGrid.Model.Options.ListBoxSelectionMode = GridSelectionMode.MultiExtended;
We have prepared a sample based on this and you can find the sample under the following location:
Sample :
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=Sample_I-152967843.zip Please let us know if this helps.
Regards,
Manikandan