How to display related data from dataset in wpf datagrid

Question

I've got a dataset with two tables, a simple one to many parent child relationship going on. eg;

Parent Table
ParentId (int)
Name     (string)

Child Table
ChildId (int)
ParentId (int)
Name     (string)

In this dataset I've got a relationship (ParentChildRelation) set up between the parent and child on the parent id field. And if I programtically do a Parent.getChildRows() call I see the correct related child records so I know the relationship is good.

I need to display a datagrid with a list of the parent rows and have another separate datagrid displaying the list of child records for the selected parent.

So far on my window in code behind I have

private DataSet _parentChildDataSet;
public DataSet ParentChildDataSet
{
    get
    {
        return _parentChildDataSet;
    }
    set 
    {
        _parentChildDataSet = value;
    }


    public DataView ParentView
    {
        get
        {
            return this.ParentChildDataSet.Tables["Parent"].DefaultView;
        }
    }

    public DataRelation ParentChildRelation
    {
        get
        {
            return this.ParentChildDataSet.Relations["Parent_Child"] ;
        }
    }

I also set the datacontext for the window to itself in the windows constructor eg ;

this.DataContext = this;

and in my xaml

<Grid>
    <DataGrid ItemsSource="{Binding Path=ParentView}" AutoGenerateColumns="True" Name="dataGrid1">
    </DataGrid>
    <DataGrid ItemsSource="{Binding Path=ParentChildRelation}" Name="dataGrid2" AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridTextColumn Binding="{Binding Path=Name}" Header="Name" />
        </DataGrid.Columns>
    </DataGrid>
</Grid>

However I cannot get any child records to show up in dataGrid2.

I'm binding this grid to the datarelation name is this correct?

if I bind to another property on my window ;

    public DataView ChildrenView
    {
        get
        {
            return this.ParentChildDataSet.Tables["Child"].DefaultView;
        }
    }

then I see all the records regardless of the parent as you would expect.

Thanks for any pointers anyone can give me.

Answer 1

When you return a DataView it is working but displays all.

Here you are returning a DataRelation

ItemsSource="{Binding Path=ParentChildRelation}" 

You need to return a DataView

Use the relation to produce the DataView

DataRowView.CreateChildView Method (DataRelation)