c# - Datagrid selectedItem 和数据绑定(bind)

Question

我的 UI 上显示了两个数据网格。当我在数据网格 1 上选择特定行时，我想在数据网格 2 上显示数据网格 1 的详细信息。我正在从数据库填充数据网格数据。这里是两个数据库的表结构。

注意:这两个表都是由数据库中的personid映射的

这是我到目前为止尝试过的代码

基类.cs

public class Baseclass
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected void SetProperty<T>(ref T member, T value, [CallerMemberName] string propertyName = null)
    {
        member = value;
        this.RaiseNotification(propertyName);
    }

    protected void RaiseNotification(string propertyName)
    {
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

人.cs

public class person : Baseclass
{

    private int personID;
    public int PersonID
    {
        get { return personID; }
        set { this.SetProperty<int>(ref this.personID, value); }
    }

    private string firstName;
    public string FirstName
    {
        get { return firstName; }
        set { this.SetProperty<string>(ref this.firstName, value); }
    }

    private string lastName;
    public string LastName
    {
        get { return lastName; }
        set { this.SetProperty<string>(ref this.lastName, value); }
    }

    Model _personModel = new Model();
    private ObservableCollection<person> _person = new ObservableCollection<person>();
    public ObservableCollection<person> Getpersons
    {
        get { return _person; }
        set { _person = value; OnPropertyChanged("GetPersons"); }
    }

    public person()
    {
        initializeload();
    }

    private void initializeload()
    {
        try
        {
            DataTable table = _personModel.getData();

            for (int i = 0; i < table.Rows.Count; ++i)
                Getpersons.Add(new person
                {
                 PersonID = Convert.ToInt32(table.Rows[i][0]),
                 FirstName = table.Rows[i][1].ToString(),
                 LastName = table.Rows[i][2].ToString(),
                });
        }

        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(string propertyname)
    {
        var handler = PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyname));
    }

    public class Model
    {
        public DataTable getData()
        {
            DataTable ndt = new DataTable();
            SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString);
            sqlcon.Open();
            SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM [Person].[dbo].[persons]", sqlcon);
            da.Fill(ndt);
            da.Dispose();
            sqlcon.Close();
            return ndt;
        }
    }

}

PersonDetail 类

public  class PersonDetails : Baseclass
{
    private int personID;
    public int PersonID
    {
        get { return personID; }
        set { this.SetProperty<int>(ref this.personID, value); }
    }

    private string address;
    public string Address
    {
        get { return address; }
        set { this.SetProperty<string>(ref this.address, value); }
    }

    private string pos;
    public string Position
    {
        get { return pos; }
        set { this.SetProperty<string>(ref this.pos, value); }
    }

    DetailsModel _detailModel = new DetailsModel();
    private ObservableCollection<PersonDetails> _details = new ObservableCollection<PersonDetails>();
    public ObservableCollection<PersonDetails> GetDetails
    {
        get { return _details; }
        set { _details = value; OnPropertyChanged("GetDetails"); }
    }
    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(string propertyname)
    {
        var handler = PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyname));
    }

    public PersonDetails()
    {
        initializeload();
    }

    private void initializeload()
    {
        try
        {
            DataTable table = _detailModel.getData();

            for (int i = 0; i < table.Rows.Count; ++i)
                GetDetails.Add(new PersonDetails
                {
                    PersonID = Convert.ToInt32(table.Rows[i][0]),
                    Address = table.Rows[i][1].ToString(),
                    Position = table.Rows[i][2].ToString(),                        
                });
        }

        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }
    public class DetailsModel
    {
        public DataTable getData()
        {
            DataTable ndt = new DataTable();
            SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString);
            sqlcon.Open();
            SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM [Person].[dbo].[personDetails]", sqlcon);
            da.Fill(ndt);
            da.Dispose();
            sqlcon.Close();
            return ndt;
        }
    }
}

MainViewModel.cs

    public class MainViewModel : Base, INotifyPropertyChanged
{
    public MainViewModel()
    {
    }

    private ObservableCollection<person> personValues;
    public ObservableCollection<person> Persons
    {
        get { return personValues; }
        set
        {
            this.SetProperty<ObservableCollection<person>>(ref this.personValues, value);
        }
    }

    private ObservableCollection<PersonDetails> detailsValues;
    public ObservableCollection<PersonDetails> Details
    {
        /* This is correct below ?? I have an error as 
        'PersonDemo.MainViewModel' does not contain a definition for 'GetDetails' and no extension method 'GetDetails' accepting a first argument of type 'PersonDemo.MainViewModel' could be found (are you missing a using directive or an assembly reference?)*/
        get { return this.GetDetails(this.Selectedperson.PersonID); }
    }

    private person selectedValue;
    public person Selectedperson
    {
        get { return selectedValue; }
        set
        {
            this.SetProperty<person>(ref this.selectedValue, value);
            this.RaiseNotification("Details");
        }
    }


}

XAML

  <Grid>
  <DataGrid Margin="100,20,116,211" ItemsSource="{Binding Persons}" SelectedItem="{Binding Selectedperson}"  />
  <DataGrid Margin="100,130,116,101" ItemsSource="{Binding Details}" />
  </Grid>

有人可以帮助继续编写 MainViewModel 吗？几周以来我一直被困在这里。

Answer 1

首先，我建议在基类中使用INotifyPropertyChanged 接口(interface)。也许您使用它而忘记将其写在示例代码中。要使用 MVVM 模式实现这一点，您需要为两个数据网格实现一个 ViewModel。我们在示例中将其称为BothGridViewModel，您可以随意调用它。然后在这个 View 模型中你需要所有的人的集合，我们称之为AllPerson，然后你需要有一个Person类型的属性，当你有被选中的人时在网格中，我们称它为 SelectedPerson。它将是这样的:

public class BothGridViewModel:INotifyPropertyChanged
{
    ...
    public ObservableCollection<Person> AllPersons {...}
    public Person SelectedPerson {...}
    ...
}

您只需在 View 的 DataContext 中设置它。和绑定(bind):

<YourView DataContext={Binding SomeBothGridViewModelClass}>
    <Grid>
     <DataGrid Margin="100,20,116,211" ItemsSource="{Binding AllPersons}" SelectedItem="{Binding SelectedPerson}"  />
     <DataGrid Margin="100,130,116,101" ItemsSource="{Binding SelectedPerson.Getpersons}" /> <!--Or some SelectedPerson.PersonDetails.GetDetails-->
  </Grid>
</YourView DataContext={Binding SomeBothGridViewModelClass}>

我认为这是制作您想要的东西的良好 View 模型结构。希望这对你有帮助...

---

编辑

---

我现在明白你的意思了，你有两个数据库表，一个用于主要属性，另一个用于详细信息。我看到两个很好的方法来做到这一点:1)第一个，我不相信第二个数据网格对于每个人来说都是必要的，因为你没有详细信息的集合。相反，您可以使用网格和其他控件来显示属性。另外我认为你必须为这个人实现一个 View 模型，例如:

public class PersonViewModel:INotifyPropertyChanged
{
     public string FirstName {...}
     public string LastName {...}
     //Other properties

     public PersonDetails Details {...}
}

然后在网格中，您可以将项目源绑定(bind)到 PersonViewModel 的集合，然后您可以绑定(bind)到网格的选定项目，例如:

<Grid>
    <DataGrid x:Name="dataGrid" ItemsSource={Binding AllPersonViewModels}/>
    ...
    <!--Then some combo box, text block or text box binding to a property of the selected item's details-->
          ...
          <TextBox Text={Binding SelectedItem.Details.Address, ElementName=dataGrid}/>
          ...
<Grid>

2) 我认为可以采用的第二种方法是在同一个数据网格中显示所有数据。为此，您需要以这种方式执行 PersonViewModel 类:

public class PersonViewModel:INotifyPropertyChanged
{
     public string FirstName {...}
     public string LastName {...}
     //Other properties

     //Then the Details properties
     public string Address {...}
     //...
     //Note this class is like a wrapper for person, and person details
}

这种方式比较简单，但可能会导致不需要的数据库过度访问。

---

编辑 2

---

看完你的代码后，我不得不说几句:在 PersonViewModel 和 PersonDetailViewModel 中，你应该使用 DispatcherTimer 而不是 Timer，因为我们在 Wpf 中。其他的，也许你应该使用 Repository 模式，创建一个 PersonRepository 和一个 PersonDetailRepository 来放置所有的数据库通信，事实上，PersonViewModel 和 PersonDetailViewModel 在某种程度上是存储库，但现在您不需要更改它，它应该可以工作。我将在这里向您展示 MainViewModel 的代码，我指定它具有 SelectedPersonDetail 属性，这样，您需要做的就是在 View 中进行绑定(bind):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using tryout13022013.PersonViewModels;
using System.ComponentModel;
using tryout13022013.DetailsViewModel;
using tryout13022013.PersonModel;

namespace tryout13022013
{
    public class MainViewModel
    {
        private PersonViewModel _subPerson = new PersonViewModel();
        public PersonViewModel SubPerson
        {
            get 
            {
                return _subPerson;
            }
            set
            {
                if (_subPerson != value)
                {
                    _subPerson = value; OnPropertyChanged("SubPerson");

                }
            }
        }


        private PersonDetailsViewModel _subDetail = new PersonDetailsViewModel();
        public PersonDetailsViewModel SubDetail
        {
            get { return _subDetail; }
            set 
            {
                _subDetail = value; OnPropertyChanged("SubDetail");
            }

        }

        private Person _selectedPerson;
        public Person SelectedPerson
        {
            get { return _selectedPerson; }
            set {
                if (_selectedPerson != value)
                {
                    _selectedPerson = value;
                    OnPropertyChanged("SelectedPerson");
                    OnPropertyChanged("SelectedPersonDetail");  //In this way when Change the Selected Person, the Selected Detail will be changed again...
                    //if (this.SelectedPerson != null && this.SubDetail != null)
                    //{
                       // I dont know how to call the PersonDetailsViewModel class like a method here in order to load its data. kindly help
                       //this.SubDetail.MethodforLoadingPersonDetails(this.SelectedPerson);
                    //}
                }
            }

        }

        public PersonDetails SelectedPersonDetail
        {
            get
            {
                if (SubDetail == null || SelectedPerson ==null)
                    return  null;
                return SubDetails.DetailsData.FirstOrDefault(detail => detail.PersonID == SelectedPerson.PersonID);
            }           

        }


        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propertyname)
        {
            var handler = PropertyChanged;
            if (handler != null)
                handler(this, new PropertyChangedEventArgs(propertyname));
        }
    }
}

这是您可以在 View 中创建的绑定(bind)实例，在本例中用于选择第二个网格中的项目:

<Window x:Class="tryout13022013.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:person="clr-namespace:tryout13022013.PersonViewModels"
    xmlns:details="clr-namespace:tryout13022013.DetailsViewModel"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <DataGrid ItemsSource="{Binding SubPerson.PersonData}"  SelectedItem="{Binding SelectedPerson, Mode=TwoWay}"
        AutoGenerateColumns="False" Height="77" HorizontalAlignment="Left"
        Margin="101,26,0,0" Name="dataGrid1" VerticalAlignment="Top" Width="auto" >
        <DataGrid.DataContext>
            <person:PersonViewModel/>
        </DataGrid.DataContext>
        <DataGrid.Columns>
            <DataGridTextColumn Header="ID" Width="auto" Binding="{Binding PersonID}"/>
            <DataGridTextColumn Header="First Name" Width="auto" Binding="{Binding FirstName}"/>
            <DataGridTextColumn Header="Last Name" Width="auto" Binding="{Binding LastName}"/>     
        </DataGrid.Columns>
    </DataGrid>


    <DataGrid ItemsSource="{Binding SubDetail.DetailsData}" 
        AutoGenerateColumns="False" Height="77" HorizontalAlignment="Left" 
        Margin="101,135,0,0" Name="dataGrid2" VerticalAlignment="Top" Width="255" SelectedItem="{Binding SelectedPersonDetail, Mode=OneWayToSource}">
        <DataGrid.DataContext>
            <details:PersonDetailsViewModel/>
        </DataGrid.DataContext>
        <DataGrid.Columns>
            <DataGridTextColumn Header="ID" Width="auto" Binding="{Binding PersonID}"/>
            <DataGridTextColumn Header="Address" Width="auto" Binding="{Binding Address}"/>
            <DataGridTextColumn Header="Position" Width="auto" Binding="{Binding Description}"/>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

我忘了，你需要绑定(bind)SubPerson.PersonData和SubDetail.DetailsData，这些是集合。检查一下...