public void Zoiper_OnAccountIncomingCall(Account account, Call call) { ActiveUsers[UserId].MakeCall(call); DialogResult result = MessageBox.Show("Accept call from: " + call.CalleeName, "Incomming call", MessageBoxButtons.YesNo); if (result == System.Windows.Forms.DialogResult.Yes) { var res = call.AcceptCall(); if ((ResultCode.Ok == res.Code) && !ActiveUsers[UserId].ActiveCalls.Keys.Contains(call.CallHandle)) { ActiveUsers[UserId].ActiveCalls.Add(call.CallHandle, call); } } else { call.HangUp(); } if (OnZoiperEvent != null) { OnZoiperEvent("AccountIncomingCall: " + call.CalleeName + " number: " + call.CalleeNumber); } }