Merge pull request #2 from SyncfusionExamples/855639_UpdateReadme

855639_Updated Readme file

Author: Manivannan-E

README.md

@@ -1,2 +1,117 @@
-# WPF-ComboBoxAdv-MultiSelection
-This repository contains the sample that how to select the items programmatically in WPF ComboBoxAdv.
+# WPF ComboBoxAdv MultiSelection
+This repository demonstrates how to select items programmatically in the Syncfusion WPF ComboBoxAdv control and enable multi-selection functionality.
+
+## Why Use ComboBoxAdv MultiSelection?
+- Allows users to select multiple items from a dropdown list.
+- Supports data binding for dynamic item updates.
+- Ideal for scenarios like filtering, tagging, or multi-choice forms.
+
+## Creating project
+Follow these steps to create a new WPF project in Visual Studio and add the ComboBoxAdv control:
+
+### Adding Control Manually in XAML
+
+1. Add the required assembly reference:
+   - Syncfusion.Shared.WPF
+
+2. Import the Syncfusion WPF schema:
+```XAML
+xmlns:syncfusion="http://schemas.syncfusion.com/wpf"
+```
+
+3. Declare the ComboBoxAdv in XAML:
+```XAML
+<Grid>
+    <syncfusion:ComboBoxAdv Height="30" Width="150"/>
+</Grid>
+```
+
+### Adding Control Manually in C#
+
+1. Add the required assembly reference:
+   - Syncfusion.Shared.WPF
+
+2. Import the namespace:
+```C#
+using Syncfusion.Windows.Tools.Controls;
+```
+
+3. Create and configure the ComboBoxAdv instance:
+```C#
+public partial class MainWindow : Window
+{
+    public MainWindow()
+    {
+        InitializeComponent();
+        ComboBoxAdv comboBoxAdv = new ComboBoxAdv
+        {
+            Height = 30,
+            Width = 150,
+            DefaultText = "Choose Items"
+        };
+        this.Content = comboBoxAdv;
+    }
+}
+```
+## ComboBoxAdv MultiSelection Example
+Enable multi-selection and bind data using MVVM:
+
+**[XAML]**
+```XAML
+<Window.DataContext>
+    <local:ViewModel />
+</Window.DataContext>
+
+<Grid>
+    <syncfusion:ComboBoxAdv DisplayMemberPath="Name"
+                             SelectedItems="{Binding SelectedItems, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
+                             AllowMultiSelect="True"
+                             Name="comboboxadv"
+                             HorizontalAlignment="Center"
+                             Height="30"
+                             VerticalAlignment="Center"
+                             Width="150"
+                             ItemsSource="{Binding Countries}"/>
+</Grid>
+```
+**ViewModel**
+```C#
+public class ViewModel : INotifyPropertyChanged
+{
+    private ObservableCollection<object> selectedItems;
+    public ObservableCollection<object> SelectedItems
+    {
+        get => selectedItems;
+        set
+        {
+            selectedItems = value;
+            RaisePropertyChanged(nameof(SelectedItems));
+        }
+    }
+
+    public ObservableCollection<Country> Countries { get; set; }
+
+    public ViewModel()
+    {
+        Countries = new ObservableCollection<Country>
+        {
+            new Country() { Name = "Denmark" },
+            new Country() { Name = "New Zealand" },
+            new Country() { Name = "Canada" },
+            new Country() { Name = "Russia" },
+            new Country() { Name = "Japan" }
+        };
+
+        SelectedItems = new ObservableCollection<object>(Countries.Take(2));
+    }
+
+    public event PropertyChangedEventHandler PropertyChanged;
+    private void RaisePropertyChanged(string propertyName)
+        => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+}
+
+public class Country
+{
+    public string Name { get; set; }
+}
+```