You can use a class type object to return select query in place of SampleMaster(if samplemastr is a table).
var varRes = db.ExecuteQuery<classname>(@TxtQry.Text, objects).ToList();
if (varRes == null)
lblErr.Text = "Information : No Records Found with given search criteria..!";
gv_Account.DataSource = varRes;
gv_Account.DataBind();</classname>
class declaration
public class className
{
}