Getting error when search name which contains ' singe quote

I am using .net handler for combo.
But when try to search client Name which contains ’ (single quote). It gives unclosed quotation error.(attached in screen shot)
Please suggest how can i fix this issue.

Here is code which i added to search like %Search Text%
void connector_BeforeSelect(object sender, EventArgs e)
var request = (sender as dhtmlxComboConnector).Request;
var rule = request.Rules.SingleOrDefault(
//seeking for the needed rule by the field name as FieldRule;
r => (r is FieldRule) && ((r as FieldRule).Field == (TableField)“clientName”));

        if (rule != null)
            //sets the '%mask%' pattern instead of 'mask%'   
            ((dhtmlxConnectors.FieldRule)(rule)).Value = "%" + ((dhtmlxConnectors.FieldRule)(rule)).Value;