将DataTable绑定到DataGrid C＃WPF MVVM

Question

New to MVVM and struggling to figure out where I went wrong when attempting to bind a dynamically generated DataTable with a DataGrid. I've found some solutions and attempted to make adjustments to my implementation based on previous responses:

XAML:

<DataGrid x:Name="Grid" Margin="5,0,0,0" ItemsSource="{Binding dataTable, Mode=TwoWay}" AutoGenerateColumns="False" VerticalAlignment="Center">
<DataGrid.Columns>
    <DataGridTextColumn Header="Header1" Binding="{Binding Column1Name}"/>
    <DataGridTextColumn Header="Header2" Binding="{Binding Column2Name}"/>
</DataGrid.Columns>
<DataGrid.DataContext>
    <ViewModels:Presenter/>
</DataGrid.DataContext>

XAML CS:

DataTable dataTable = new DataTable();
Grid.DataContext = dataTable.DefaultView;
//I don't believe I should be using System.Data in View?

ViewModel

.Presenter:

public class Presenter : ObservableObject {
private DataTable _dataTable;


public DataTable dataTable
    {
        get { return _dataTable; }
        set
        {
            _dataTable = value;
            RaisePropertyChangedEvent("Grid");
        }
    }

private void ParseData()
    {
        if (string.IsNullOrWhiteSpace(ID)) return;
        dataTable = DataParser.ParseURL(ID);
    }
}

.ObservableObject

public class ObservableObject : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected void RaisePropertyChangedEvent(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyName));
    }
}

I know the data from the model is returning correctly, and when I'm in debugger the RaisePropertyChangedEvent is firing, but the view is not being updated.

Answer 1

You're raising the wrong PropertyName (which appears to be the name of your Grid in the XAML.

Raise the name "dataTable" when calling your RaisePropertyChanged method.

Like so:

public DataTable dataTable
{
    get { return _dataTable; }
    set
    {
        _dataTable = value;
        RaisePropertyChangedEvent("dataTable");
    }
}

---

A few other things you can do are:

• Use [CallerMemberName] attribute before the propertyName parameter. This will save you having to provide it, as it detects what property is calling it (C#5 and above) - eg: protected void RaisePropertyChangedEvent([CallerMemberName] string propertyName)
• Use PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); in your RaisePropertyChanged method. This saves you having to create a variable and check for null (C#6 and above)
• Rename your dataTable property to DataTable - it creates better clarity as to what are properties and what are fields, and it's a commonplace thing to do in C#

---

Hope this helps :)

Answer 2

Since you are setting the DataContext of the DataGrid to the DataView of the DataTable like this:

Grid.DataContext = dataTable.DefaultView;

...you should bind directly to the DataContext :

<DataGrid x:Name="Grid" Margin="5,0,0,0" ItemsSource="{Binding}" AutoGenerateColumns="False" VerticalAlignment="Center">
...

If you want to bind to your dataTable property, you should set the DataContext to an instance of your Presenter class:

var p = new Presenter();
Grid.DataContext = p;

---

<DataGrid x:Name="Grid" Margin="5,0,0,0" ItemsSource="{Binding dataTable}" AutoGenerateColumns="False" VerticalAlignment="Center">

Then you can set the dataTable property of the Presenter object to a new DataTable :

p.dataTable = new DataTable();

You still need to modify your property as suggested by @Geoff James:

public DataTable dataTable
{
    get { return _dataTable; }
    set
    {
        _dataTable = value;
        RaisePropertyChangedEvent("dataTable");
    }
}