DataGrid不显示外键值为空的行

Question

I have a WPF DataGrid :

<DataGrid.Columns>
    <DataGridTextColumn Binding="{Binding SalesInvoiceID}" Header="Sales Invoice ID" Width="100"/>
    <DataGridTextColumn Binding="{Binding CustomerID}" Header="Customer ID" Width="100"/>                  
</DataGrid.Columns>

CustomerID is a foreign key which can be null in database. DataGrid Does not show those rows who's CustomerID is null. Please help.

I want to show all rows including those rows also who's CustomerID field( which is foreign key) is null . i used the following query in c#

select s.SalesInvoiceID,c.CustomerID from SalesInvoiceID s inner join Customer c on s.CustomerID=c.CustomerID

I want

SalesInvoiceID  CustomerID
---------------------------
1               23
2               Null
3               24
4               Null   

Answer 1

It is not displaying those rows because you are not giving it those rows

Test your query in SSMS

SELECT s.SalesInvoiceID, c.CustomerID 
from SalesInvoiceID s 
inner join Customer c 
   on s.CustomerID = c.CustomerID

Try

left join Customer c