Drop from 3 clicks to 1 to edit transactions

src/MoneyMan.WPF/App.xaml.cs

@@ -8,6 +8,7 @@ namespace MoneyMan
 	using System.Reflection;
 	using System.Runtime.InteropServices;
 	using System.Windows;
+	using System.Windows.Controls;
 	using Squirrel;
 
 	/// <summary>
@@ -49,5 +50,15 @@ internal static UpdateManager CreateUpdateManager()
 				  urlOrPath: $"https://moneymanreleases.blob.core.windows.net/releases/{channel}/{subchannel}/",
 				  applicationName);
 		}
+
+		protected override void OnStartup(StartupEventArgs e)
+		{
+			base.OnStartup(e);
+
+			EventManager.RegisterClassHandler(
+				typeof(DataGrid),
+				DataGrid.PreviewMouseLeftButtonDownEvent,
+				new RoutedEventHandler(WpfHelpers.DataGridPreviewMouseLeftButtonDownEvent));
+		}
 	}
 }

src/MoneyMan.WPF/MainWindow.xaml

@@ -78,6 +78,7 @@
 						<DataGrid Name="TransactionDataGrid"
 								  AlternatingRowBackground="LightBlue"
 								  AlternationCount="2" 
+								  PreparingCellForEdit="TransactionDataGrid_PreparingCellForEdit"
 								  ItemsSource="{Binding Source={StaticResource transactions}}"
 								  IsSynchronizedWithCurrentItem="True"
 								  SelectedItem="{Binding Document.SelectedTransaction, Source={StaticResource viewModel}, Mode=TwoWay, TargetNullValue={x:Static CollectionView.NewItemPlaceholder}}"

src/MoneyMan.WPF/MainWindow.xaml.cs

@@ -195,5 +195,10 @@ private async Task UpdateApplicationAsync()
 				// This is newer than the latest stable version.
 			}
 		}
+
+		private void TransactionDataGrid_PreparingCellForEdit(object sender, DataGridPreparingCellForEditEventArgs e)
+		{
+			WpfHelpers.GetFirstChildByType<Control>(e.EditingElement)?.Focus();
+		}
 	}
 }

src/MoneyMan.WPF/WpfHelpers.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Andrew Arnott. All rights reserved.
+// Licensed under the Ms-PL license. See LICENSE.txt file in the project root for full license information.
+
+namespace MoneyMan
+{
+	using System.Windows;
+	using System.Windows.Controls;
+	using System.Windows.Input;
+	using System.Windows.Media;
+
+	public static class WpfHelpers
+	{
+		internal static void DataGridPreviewMouseLeftButtonDownEvent(object sender, RoutedEventArgs e)
+		{
+			// The original source for this was inspired by https://softwaremechanik.wordpress.com/2013/10/02/how-to-make-all-wpf-datagrid-cells-have-a-single-click-to-edit/
+			DataGridCell? cell = e is MouseButtonEventArgs { OriginalSource: UIElement clickTarget } ? FindVisualParent<DataGridCell>(clickTarget) : null;
+			if (cell is { IsEditing: false, IsReadOnly: false })
+			{
+				if (!cell.IsFocused)
+				{
+					cell.Focus();
+				}
+
+				if (FindVisualParent<DataGrid>(cell) is DataGrid dataGrid)
+				{
+					if (dataGrid.SelectionUnit != DataGridSelectionUnit.FullRow)
+					{
+						if (!cell.IsSelected)
+						{
+							cell.IsSelected = true;
+						}
+					}
+					else
+					{
+						if (FindVisualParent<DataGridRow>(cell) is DataGridRow { IsSelected: false } row)
+						{
+							row.IsSelected = true;
+						}
+					}
+				}
+			}
+		}
+
+		internal static T? GetFirstChildByType<T>(DependencyObject prop)
+			where T : DependencyObject
+		{
+			int count = VisualTreeHelper.GetChildrenCount(prop);
+			for (int i = 0; i < count; i++)
+			{
+				if (VisualTreeHelper.GetChild(prop, i) is DependencyObject child)
+				{
+					T? typedChild = child as T ?? GetFirstChildByType<T>(child);
+					if (typedChild is object)
+					{
+						return typedChild;
+					}
+				}
+			}
+
+			return null;
+		}
+
+		private static T? FindVisualParent<T>(UIElement element)
+			where T : UIElement
+		{
+			UIElement? parent = element;
+			while (parent is object)
+			{
+				if (parent is T correctlyTyped)
+				{
+					return correctlyTyped;
+				}
+
+				parent = VisualTreeHelper.GetParent(parent) as UIElement;
+			}
+
+			return null;
+		}
+	}
+}