如何在我的方案中使用 MVVM 动态更新数据网格

很简单，就像向ObservableCollection<Model> DGrid添加新模型一样：

 class ViewModel
    {
        public bool canExecute { get; set; }
        private RelayCommand saveStudentRecord; 
        private ObservableCollection<Model> dGrid;
        public ViewModel()
        {
            dGrid = new ObservableCollection<Model>();
        }
        private void MyAction()
        {
           dGrid.Add(new Model(){
               TextName = valueOfTextTextBox,
               RollNumber = valueOfRollNumberTextBox,
               Class = valueOfClassTextBox
           });
        }     
    }

这里要记住的事情：dGrid 应该是一个公共属性，因此您可以将数据绑定与它一起使用，例如：

public ObservableCollection<Model> dGrid {
    get;
    private set;
}

根据表彰中的问题进行编辑：

您需要将文本框的文本属性绑定到 ViewModel 上的属性。由于ModelClass拥有这种信息，我会这样做：

 class ViewModel
    {
        public bool canExecute { get; set; }
        private RelayCommand saveStudentRecord; 
        private ObservableCollection<Model> dGrid;
        public ViewModel()
        {
            dGrid = new ObservableCollection<Model>();
        }
        public Model EditedModel {
            get {
                return _editedModel;
            }
            set {
                _editedModel = value;
                SignalPropertyChanged("EditedModel");
            }
        }
        private void MyAction()
        {
           dGrid.Add(EditedModel);
           EditedModel = new Model();
        }
        void SignalPropertyChanged(string propertyName){
            if(propertyChanged !=null){
                propertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

    }

当然，现在您的视图模型和模型需要实现INotifyPropertyChanged接口来通知视图更改

class Model : INotifyPropertyChanged
{
    private string textName;
    public string TextName
    {
        get { return textName; }
        set { 
            textName = value; 
            SignalPropertyChanged("TextName");
         }
    }
    private string rollNumber;
    public string RollNumber
    {
        get { return rollNumber; }
        set { 
            rollNumber= value; 
            SignalPropertyChanged("RollNumber");
         }
    }
    private string cclass;
    public string Class
    {
        get { return cclass; }
        set { 
            cclass= value; 
            SignalPropertyChanged("Class");
         }
    }
    public event PropertyChangedEventHandler propertyChanged;
    void SignalPropertyChanged(string propertyName){
        if(propertyChanged !=null){
            propertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

编辑2 - 忘记添加 XAML 部件:)您需要将文本框绑定到新属性

<Window x:Class="WpfApplication4.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition></RowDefinition>
            <RowDefinition Height="30"></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <Grid Grid.Row="0">
            <Grid.RowDefinitions>
                <RowDefinition></RowDefinition>
                <RowDefinition></RowDefinition>
                <RowDefinition></RowDefinition>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition></ColumnDefinition>
                <ColumnDefinition></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <TextBox Grid.Column="1" Grid.Row="0" Text="{Binding EditedModel.TextName}" Height="20" Width="80" HorizontalAlignment="Center"></TextBox>
            <TextBox Grid.Column="1" Grid.Row="1" Text="{Binding EditedModel.RollNumber}"  Height="20" Width="80"></TextBox>
            <TextBox Grid.Column="1" Grid.Row="2" Text="{Binding EditedModel.Class}" Height="20" Width="80"></TextBox>
            <Label Grid.Row="0" HorizontalAlignment="Center" VerticalAlignment="Center">Name</Label>
            <Label Grid.Row="1" HorizontalAlignment="Center" VerticalAlignment="Center">RollNumber</Label>
            <Label Grid.Row="2" HorizontalAlignment="Center" VerticalAlignment="Center">Class</Label>
        </Grid>
        <Grid Grid.Row="1" >
            <Button Width="80" Height="20" Command="{Binding saveStudentRecord}"> Save</Button>
        </Grid>
        <Grid Grid.Row="2">
            <DataGrid ItemsSource="{Binding DGrid}">
                <DataGrid.Columns>
                    <DataGridTextColumn Header="Name" Binding="{Binding dgName}" Width="150"></DataGridTextColumn>
                    <DataGridTextColumn Header="Rollnumber" Binding="{Binding dgRollnumber}" Width="150"></DataGridTextColumn>
                    <DataGridTextColumn Header="Class" Binding="{Binding dgClass}" Width="150"></DataGridTextColumn>
                </DataGrid.Columns>
            </DataGrid>
        </Grid>
    </Grid>
</Window>