How to pass data from MainWindow to multiple viewmodels

Question

Hi, I have the following codes where I want to pass dropdown selected data from one window to another window's viewmodel. For example, I want to pass values selected from the dropdowns in MainWindow to ChartViewModel. How do I achieve this? Also, how do I change title of ChartWindow using the values selected from the dropdowns in MainWindow?MainWindow.xaml: Market: Delivery Month: Country: Date: MainWindow.xaml.cs:using Syncfusion.Windows.Shared;using Syncfusion.Windows.Tools.Controls;using System.Windows;namespace SyncfusionWpfDropdownTest{ ///

/// Interaction logic for MainWindow.xaml ///

public partial class MainWindow : Window { string selectedCountry = ""; string selectedMarket = ""; string selectedDeliveryMonth = ""; Date selectedStartDate = new Date(); Date selectedEndDate = new Date(); public MainWindow() { InitializeComponent(); } private void DropDownMenuItem_CountryClick(object sender, RoutedEventArgs e) { selectedCountry = (sender as DropDownMenuItem)?.Header?.ToString()?? string.Empty; CountryDropDown.Label = selectedCountry; viewModel.CountrySavedValue = selectedCountry; } private void DropDownMenuItem_MarketClick(object sender, RoutedEventArgs e) { selectedMarket = (sender as DropDownMenuItem)?.Header?.ToString()?? string.Empty; MarketDropDown.Label = selectedMarket; viewModel.MarketSavedValue = selectedMarket; } private void DropDownMenuItem_DeliveryMonthClick(object sender, RoutedEventArgs e) { selectedDeliveryMonth = (sender as DropDownMenuItem)?.Header?.ToString()?? string.Empty; DeliveryMonthDropDown.Label = selectedDeliveryMonth; viewModel.DeliveryMonthSavedValue = selectedDeliveryMonth; } private void ButtonAdvItem_ChartButtonClick(object sender, RoutedEventArgs e) { ChartWindow chartWindow = new ChartWindow(); chartWindow.Show(); } private void ButtonAdvItem_TableButtonClick(object sender, RoutedEventArgs e) { List startDates = DateCalendarEditStart.SelectedDatesList; List endDates = DateCalendarEditEnd.SelectedDatesList; if (startDates != null && startDates.Count > 0) { Date startDate = startDates.Min(); } if (endDates != null && endDates.Count > 0) { Date endDate = endDates.Max(); } } }}ViewModel.cs:using System.Collections.ObjectModel;using System.Web;using Npgsql;namespace SyncfusionWpfDropdownTest{ public class ViewModel { private string _countrySavedValue = string.Empty; private string _marketSavedValue = string.Empty; private string _deliverymonthSavedValue = string.Empty; public ObservableCollection Countries { get; set; } public ObservableCollection Markets { get; set; } public ObservableCollection DeliveryMonths { get; set; } public string CountrySavedValue { get { return _countrySavedValue; } set { _countrySavedValue = value; } } public string MarketSavedValue { get { return _marketSavedValue; } set { _marketSavedValue = value; MakeDeliveryMonthQuery(); } } public string DeliveryMonthSavedValue { get { return _deliverymonthSavedValue; } set { _deliverymonthSavedValue = value; } } private void MakeDeliveryMonthQuery() { DeliveryMonths.Clear(); NpgsqlConnection conn2 = new NpgsqlConnection("Host=192.168.1.2; Port=5432; Database=tradingapp; Username=vorlket; Password=Vcsokr."); conn2.Open(); string query2 = "SELECT DISTINCT \"Delivery Month\" FROM Futures WHERE Name = '" + MarketSavedValue + "' ORDER BY \"Delivery Month\""; NpgsqlCommand cmd2 = new NpgsqlCommand(query2, conn2); NpgsqlDataReader reader2 = cmd2.ExecuteReader(); while (reader2.Read()) { DeliveryMonths.Add(new DeliveryMonth { Month = reader2.GetString(0) }); } } public ViewModel() { Countries = new ObservableCollection(); Markets = new ObservableCollection(); DeliveryMonths = new ObservableCollection(); LoadData(); } private void LoadData() { NpgsqlConnection conn = new NpgsqlConnection("Host=192.168.1.2; Port=5432; Database=tradingapp; Username=vorlket; Password=Vcsokr."); conn.Open(); string query = "SELECT DISTINCT Country FROM EconomicCalendar ORDER BY Country"; NpgsqlCommand cmd = new NpgsqlCommand(query, conn); NpgsqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { Countries.Add(new Country { Name = reader.GetString(0) }); } NpgsqlConnection conn1 = new NpgsqlConnection("Host=192.168.1.2; Port=5432; Database=tradingapp; Username=vorlket; Password=Vcsokr."); conn1.Open(); string query1 = "SELECT DISTINCT Name FROM Futures ORDER BY Name"; NpgsqlCommand cmd1 = new NpgsqlCommand(query1, conn1); NpgsqlDataReader reader1 = cmd1.ExecuteReader(); while (reader1.Read()) { Markets.Add(new Market { Name = reader1.GetString(0) }); } } }}ChartWindow.xaml: ChartViewModel.cs:using Npgsql;using System.Collections.ObjectModel;namespace SyncfusionWpfDropdownTest{ public class ChartViewModel { private string _marketSavedValue = string.Empty; private string _deliverymonthSavedValue = string.Empty; public ObservableCollection Markets { get; set; } public ObservableCollection DeliveryMonths { get; set; } public string MarketSavedValue { get { return _marketSavedValue; } set { _marketSavedValue = value; } } public string DeliveryMonthSavedValue { get { return _deliverymonthSavedValue; } set { _deliverymonthSavedValue = value; } } public ObservableCollection Futures { get; set; } public ChartViewModel() { Markets = new ObservableCollection(); DeliveryMonths = new ObservableCollection(); Futures = new ObservableCollection(); LoadData(); } private void LoadData() { NpgsqlConnection conn = new NpgsqlConnection("Host=192.168.1.2; Port=5432; Database=tradingapp; Username=vorlket; Password=Vcsokr."); conn.Open(); string query = "SELECT Date, High, Open, Close, Low, Volume, \"Open Interest\" FROM Futures WHERE Name = '" + MarketSavedValue + "' and \"Delivery Month\"='" + DeliveryMonthSavedValue + "'"; NpgsqlCommand cmd = new NpgsqlCommand(query, conn); NpgsqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { Futures.Add(new Futures { Date = reader.GetDateTime(0), High = reader.GetDouble(1), Open = reader.GetDouble(2), Close = reader.GetDouble(3), Low = reader.GetDouble(4), Volume = reader.GetInt32(5), OpenInterest = reader.GetInt32(6) }); } } }}

Priyanka Vijayasankar · Accepted Answer

Hi Kook Jin Noh, We have reviewed
your query and created a sample to meet your requirements. Please find the
attached sample below and let us know if you need any further assistance. Regards,Priyanka VijayasankarAttachment: DropDownButton_9ccb98.zip