how... custom Autocomplete for Combobox and Search same "like" in SQL

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C#

MVC

hi
i want to change Autocomplete in combo box when i type for example "zar",Autocomplete show me this list :

zar
raezarye
zarbaf
bafzar
zarif

in default Autocomplete in combo box show this list :

zar
zarbaf
zarif

but i don't want it , i write this code in key press but not work :

private void frmProjects_Load(object sender, EventArgs e)
        {
var ListMohandesin = (from item in _db.UserProfiles
                                      orderby item.Family
                                      select new
                                      {
                                          DisplayMember = item.Name + " " + item.Family,
                                          ValueMember = item.UserId
                                      }).ToList();

                mcmbTMemary.DataSource = ListMohandesin;
                mcmbTMemary.DisplayMember = "DisplayMember";
                mcmbTMemary.ValueMember = "ValueMember";
                mcmbTMemary.SelectedIndex = -1;
                mcmbTMemary.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
                mcmbTMemary.AutoCompleteSource = AutoCompleteSource.CustomSource;

}
 private void mcmbTMemary_KeyPress(object sender, KeyPressEventArgs e)
        {
            
                     
           mcmbTMemary.AutoCompleteCustomSource.OfType<string>().Where(a => a.ToLower().Contains(mcmbTMemary.Text.ToLower())).Any();
        }

please help me
tanks