feat: Add export to CSV functionality

Author: DerekGooding

SimpleDataGrid.Example/AdvancedExamplesViewModel.cs

@@ -3,6 +3,8 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
+using System.IO;
+using System.Reflection;
 
 namespace SimpleDataGrid.Example;
 
@@ -79,6 +81,29 @@ public void ApplyCustomFilter()
         People.SetFilter("customFilter", p => p.Age > 30);
     }
 
+    public void ExportCurrentPageToCsv()
+    {
+        var items = People.CurrentPageItems;
+        if (!items.Any()) return;
+
+        var csv = new System.Text.StringBuilder();
+
+        // Add header row
+        var headers = typeof(Person).GetProperties().Select(p => p.Name);
+        csv.AppendLine(string.Join(",", headers));
+
+        // Add data rows
+        foreach (Person item in items)
+        {
+            var fields = typeof(Person).GetProperties().Select(p => p.GetValue(item)?.ToString() ?? string.Empty);
+            csv.AppendLine(string.Join(",", fields));
+        }
+
+        var filePath = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "CurrentPage.csv");
+        System.IO.File.WriteAllText(filePath, csv.ToString());
+        System.Windows.MessageBox.Show($"Current page exported to {filePath}");
+    }
+
     public event PropertyChangedEventHandler? PropertyChanged;
     protected virtual void OnPropertyChanged(string propertyName)
     {

SimpleDataGrid.Example/AdvancedExamplesWindow.xaml

@@ -90,6 +90,7 @@
             <TextBox x:Name="PageTextBox" Width="30" Margin="5,0,0,0"/>
             <Button Content="Go" Click="GoToPageButton_Click" Margin="5,0,0,0"/>
             <ComboBox Margin="10,0,0,0" ItemsSource="{Binding PageSizes}" SelectedItem="{Binding People.PageSize}"/>
+            <Button Content="Export Current Page to CSV" Click="ExportToCsvButton_Click" Margin="10,0,0,0"/>
             <TextBlock VerticalAlignment="Center" Margin="10,0,0,0">
                 <TextBlock.Text>
                     <MultiBinding Converter="{StaticResource ItemCountConverter}">

SimpleDataGrid.Example/AdvancedExamplesWindow.xaml.cs

@@ -112,4 +112,10 @@ private void ApplyCustomFilterButton_Click(object sender, RoutedEventArgs e)
         var viewModel = (AdvancedExamplesViewModel)DataContext;
         viewModel.ApplyCustomFilter();
     }
+
+    private void ExportToCsvButton_Click(object sender, RoutedEventArgs e)
+    {
+        var viewModel = (AdvancedExamplesViewModel)DataContext;
+        viewModel.ExportCurrentPageToCsv();
+    }
 }