Binding DataTable to 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.

Top tip: if you're using C#6 or above, you can use PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); instead of creating a variable and checking for null :) — Geoff James
– Geoff James, Commented May 20, 2017 at 21:01
First rename the dataTable to DataTable no the issue just annoying. Second for the name of the property use "DataTable" not "Grid" or use a proper implementation for notification. You can also use the nameof(DataGrid) in c# 6 — Filip Cordas
– Filip Cordas, Commented May 20, 2017 at 21:05
Implemented both of these suggestions; Still haven't gotten it to work, but with the changes I've made here I'm hoping that prior articles might get me up and going. — Spence
– Spence, Commented May 20, 2017 at 23:26

Geoff James · Accepted Answer · 2017-05-20 21:05:00Z

2

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) - e.g.: 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 :)

answered May 20, 2017 at 21:05

Geoff James

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1 Comment

Spence Over a year ago

Thanks for the response. I changed the name to "dataTable" and it is still not working. I'm also going to refactor based on your feedback. I have concerns that my binding in the XAML headers is not correct, could that be why its not pulling in the correct information?

mm8 · Accepted Answer · 2017-05-22 13:16:40Z

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");
    }
}

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