wpf datagrid如何添加汇总行

看下这个例子：

XML/HTML code?

1 2 3 4 5 6 7 8 9 10 11 12

<Window x:Class="WpfApp1.MainWindow"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     Title="" Height="400" Width="550" >     <DockPanel>         <StackPanel DockPanel.Dock="Bottom" Orientation="Horizontal" HorizontalAlignment="Right">             <TextBlock>Total:</TextBlock>             <TextBlock Margin="30, 0, 0, 0" Text="{Binding TotalDebit}" />             <TextBlock Margin="30, 0, 30, 0" Text="{Binding TotalCredit}" />         </StackPanel>         <DataGrid ItemsSource="{Binding Items}" />     </DockPanel>

C# code?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96

using System; using System.Collections.Generic; using System.Collections.ObjectModel; using System.ComponentModel; using System.Linq; using System.Windows; namespace WpfApp1 {     public partial class MainWindow : Window     {         public MainWindow()         {             InitializeComponent();             var r = new Random();             var testData = Enumerable.Range(1, 7).Select(i => new Voucher()                 {                     No = 145+i,                     Date = DateTime.Now.AddDays(r.Next(-5, 5)),                     Type = (AccountType)r.Next(2),                     Debit = r.Next(100),                     Credit = r.Next(100),                 });                           this.DataContext = new Vouchers(testData);         }     }     public class Vouchers : ObservableObject     {         public Vouchers(IEnumerable<Voucher> items)         {             Items = new ObservableCollection<Voucher>(items);             Items.CollectionChanged += (s, e)=> CalcTotals();             Items.ToList().ForEach(item => item.PropertyChanged += (s, e) => CalcTotals());             CalcTotals();         }         public ObservableCollection<Voucher> Items { get; private set; }         void CalcTotals()         {             TotalCredit = Items.Sum(x => x.Credit);             TotalDebit = Items.Sum(x => x.Debit);         }         private decimal _totalDebit;         public decimal TotalDebit         {             get { return _totalDebit; }             set { _totalDebit = value; OnPropertyChanged("TotalDebit"); }         }         private decimal _totalCredit;         public decimal TotalCredit         {             get { return _totalCredit; }             set { _totalCredit = value; OnPropertyChanged("TotalCredit"); }         }     }          public enum AccountType { FinancialAccount, OtherAccount }     public class Voucher : ObservableObject     {         public int No { get; set; }         public    DateTime Date { get; set; }         public    AccountType Type { get; set; }         public    string Account { get; set; }         public    string Memo { get; set; }                   private decimal _debit;         public    decimal Debit         {             get { return _debit; }             set { _debit = value; OnPropertyChanged("Debit"); }         }         private decimal _credit;         public decimal Credit         {             get { return _credit; }             set { _credit = value; OnPropertyChanged("Credit"); }         }     }     public class ObservableObject : INotifyPropertyChanged     {         public event PropertyChangedEventHandler PropertyChanged;         protected void OnPropertyChanged(string propertyName)         {             if (PropertyChanged != null)                 PropertyChanged(this, new PropertyChangedEventArgs(propertyName));         }     } }