WPF Combobox binding Question

I have a 2 Table.

Product

Product开发者_如何学GoName

CategoryID

Category

ID

CategoryName

I'm filling combobox to table named 'category'.

Code

Product currentProduct=datacontext.products.FirstOrDefault();
this.datacontext=currentProduct;
combobox1.Itemssource=datacontext.categories;

XAML

<Textbox Text="{Binding Path=ProductName}"></Textbox>
<Combobox x:Name="combobox1" SelectedItem="Binding Path=CategoryID"></Combobox>

When click save button, I'm doing datacontext.SubmitChanges()

ProductName changed. But CategoryID not changed.

My target is when i select from combobox, selected category ID set to CategoryID of currentProduct. (like currentProduct.CategoryID=(Category as combobox1.SelectedItem).ID)

How to do is from xaml?

Bind the SelectedValue property of the ComboBox to the CategoryID of the product, not the SelectedItem. You also need to set the SelectedValuePath property :

<Combobox x:Name="combobox1" SelectedValuePath=CategoryID, SelectedValue="{Binding Path=CategoryID, Mode=TwoWay}"></Combobox>