[Solved] Displaying foreign key value with entity framework?

[pantarhei]

Hello,

i'm just playing around with Silverlight and Telerik controls. for now i have a RIA Service Demo Application. at the moment

i can't figure out how to bind my fk value to the grid.

the grid itself is bound to a service that receives all cars.

//Displaying all cars in the grid

CarContext ctx = new CarContext();

carGrid.ItemsSource = ctx.Cars;

ctx.Load(ctx.GetCarsQuery());

displaying the carmakers name works in code if i manually create a GridViewComboBoxColumn an bind it to the

data receiving from a seperate service.

//Getting carmakers from a seperate carMakerService
GridViewComboBoxColumn carMakerSelect = new GridViewComboBoxColumn();
carMakerSelect.HeaderText = "Carmaker";
carMakerSelect.DataMemberBinding = new Binding("carmaker_id");
carMakerSelect.DisplayMemberPath = "name";
carMakerSelect.SelectedValueMemberPath = "id";

carMakerSelect.ItemsSource = carMakerContext.Carmakers;
carMakerContext.Load(herstellerDal.GetCarMakerQuery());

this.carGrid.Columns.Add(carMakerSelect);

 

is this the only way to connect a fk to the grid if i only like to display the fk's value? can this be done in xaml too?

 i think i'm missing something in general and it's not 100% telerik datagrid related. but perhaps you can show me the right direction. :)

regards

[Pavel Pavlov]

Hello pantarhei,

I am not sure I get the problem right but all of the following properties can be set directly in XAML to the relevant ComboBoxColumn:

HeaderText
DataMemberBinding
DisplayMemberPath
SelectedValueMemberPath
ItemsSource

Something like :

<telerik:RadGridView x:Name="RadGridView1" AutoGenerateColumns="False">
            <telerik:RadGridView.Columns>
                <telerik:GridViewComboBoxColumn DataMemberBinding="{Binding CountryID}" DisplayMemberPath="Name" SelectedValueMemberPath="ID" ...

Regarding the ItemsSource - you may provide it trough a static resource in the XAML of the page.

Kind regards,

Pavel Pavlov
the Telerik team

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[pantarhei]

Hello Pavel,

thanks for your reply. My problem was as i supposed not really Telerik specific. i forgot to set the [Include] attribute in my metadata.

result was that the carmakers have never been serialised and thus i wasn't able to display the value in the grid. i'm just at the beginning stage.

i can now display the carmakers name with the following code. 

//Query on my entity model
return this.Context.Cars.Include("Carmaker");

//Binding a Master-Value to a column
<telerikGridView:GridViewDataColumn
  HeaderText="Horsepower"
  DataMemberBinding="{Binding horsepower}" />

//Binding Detail-Value to a column
<telerikGridView:GridViewDataColumn
  HeaderText="Carmaker"
  DataMemberBinding="{Binding Carmaker.name}" />

now i have another question regarding this. the "Carmaker" column isn't showing the filter symbol. the Horsepower column is displaying it. how to filter "Detail" column?

[Pavel Pavlov]

Hello pantarhei,

The first thing I can think of is  that  the filtering icon would not display if the underlying business object does not implement IComparable or IEquatable.

Let me know if that is not the case .


Best wishes,
Pavel Pavlov
the Telerik team

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