Hi Tommie,
Thank you for contacting Syncfusion support
“Query #1: containing "Select All" checkbox”
In our current implementation,we don’t have “Select All” option to select all the items
“Query #2: Auto filter display content based on typing”
In our ComboBoxAdv, there is no support for filtering content based on typing. So we suggest you to use our AutoComplete control to achieve your requirement. We have also prepared a sample
Please find the sample from the below link:
Sample link:
AutoCompleteSampleIn the sample we have binded items to the CustomSource of the AutoComplete
Please let us know if you need any other assistance
Regards,
M.Sugapriya