Hi Subrata,
Thank you for using Syncfusion products.
If you want to sort the particular column in autocomplete , you can set them as MatchingColumn.
Please refer the sample below in which the column 'Name' used as MatchingColumn. In the sample 'Markus' selected in the dropdown initially when the application loads. if the user changes the selection 'Markus' will be the first entry in the dropdown.
Here is the sample that demonstrates this.
http://files.syncfusion.com/support/Tools.Windows/7.1.0.30/F80311/Tools_WF_Autocomplete_comboBox.zipPlease let me know if this helps you.
Regards,
Jaya