C＃列表绑定到WPF DataGrid

Question

I started to work with WPF's datagrid and faced with the problem. I have such list

private List<ChainCode> _chainCode = new List<ChainCode>();

where ChainCode is:

public class ChainCode
{
    private uint _number;
    private byte _code;

    public uint Number { get { return _number; } set { _number = value; } }
    public byte Code { get { return _code; } set { _number = value; } }
}

So, I want to bind id to such DataGrid:

<DataGrid x:Name="dataGridChainCode" ItemsSource="{Binding _chainCode}" CanUserAddRows="True" IsEnabled="False" AutoGenerateColumns="False" Margin="10,35,18,0" VerticalAlignment="Top">
    <DataGrid.Columns>
        <DataGridTextColumn Binding="{Binding Number}" IsReadOnly="True" Header="#" Width="60"/>
        <DataGridTextColumn Binding="{Binding Code}" Header="code" Width="60"/>
    </DataGrid.Columns>
</DataGrid>

but when I launch my program, I can't add any row to datagrid, cuz there is no row, only headers. And I just have no idea how to fix it.

---

Update: I made such changes:

private ObservableCollection<ChainCode> _chainCode = new ObservableCollection<ChainCode>();
public ObservableCollection<ChainCode> OCChainCode { get { return _chainCode; } set { _chainCode = value; } }

and next in xaml:

ItemsSource="{Binding OCChainCode}"

but there is no response. What I doing wrong?

---

The one thing i understood is than it's too early for me to use WPF. So, I'll try to fix it later

Answer 1

You can't bind to non-public member. Create property

public List<ChainCode> ChainCodeList
{
    get { return _chainCode;}
    set { _chainCode = value;}
}

and bind to it.

If your list will change at app lifetime you can use ObservableCollection<T> instead.

Answer 2

Use ObservableCollection instead of List and implement INotifyPropertyChanged , if you want the list to update when you change values of Number or Code.

And make your list property public or protected.

Answer 3

In order to use data binding, you need to set the DataContext of the part where you want to use the binding. There are several different ways to set the DataContext, a simple way to do it is in the constructor of the UserControl-class. Usually the DataContext is set to a ViewModel (Using the Model-View-ViewModel-pattern), but it can be any class.

public class ViewModel {
   private ObservableCollection<ChainCode> _chainCode = new ObservableCollection<ChainCode>();

   public ObservableCollection<ChainCode> OCChainCode 
   { 
       // No need for a public setter
       get { return _chainCode; }        
   }
}

UserControl-class (the class in [name].xaml.cs file):

public class MyUserControl : UserControl
{
   public MyUserControl()
   {
      DataContext = new ViewModel();
   }
}

You can now use the xaml in your question.

<DataGrid x:Name="dataGridChainCode" ItemsSource="{Binding _chainCode}" CanUserAddRows="True" IsEnabled="False" AutoGenerateColumns="False" Margin="10,35,18,0" VerticalAlignment="Top">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding Number}" IsReadOnly="True" Header="#" Width="60"/>
                <DataGridTextColumn Binding="{Binding Code}" Header="code" Width="60"/>
            </DataGrid.Columns>
        </DataGrid>

A thing to note, there are no automatic functionality to add new rows in a DataGrid, you have to write this code yourself. I would suggest a button that creates a new ChainCode-object and adds it to the Observable collection, then it will show up in the UI.