How to Overcome DomainOperationEntry overloads are not supported in C#

Question

  Hi Team ,
I have a assigmmnet to finsh . requerment is
1) I have to Comboboxes one is cmbDomain , second one is cmbSubDoamin
  based on selected value in cmbDoman , cmbSubDoamin has to fill.
 for this  I  am  using WCFRIA Serivice
In sercive I have two methods like bellow.
//for Domain
public IQueryable<DomainGroup> GetDomainGroups()
return this.ObjectContext.DomainGroups;
// for SubDoamin
public IQueryable<Domain> GetDomains()
return this.ObjectContext.Domains;
//for subdomain based on selected value in Domain
public IQueryable<Domain> GetDomains(string selectedDomain)
return this.ObjectContext.Domains.Where(x => x.Title.ToUpper() == selectedDomain.ToUpper());
in Silverlight i implimented bellow code
<riaControls:DomainDataSource x:Name="source" QueryName="GetDomainGroups" AutoLoad="True"> <riaControls:DomainDataSource.DomainContext>
<domain:DomainService1/> </riaControls:DomainDataSource.DomainContext>
</riaControls:DomainDataSource>
<riaControls:DomainDataSource x:Name="SubDomainSource" QueryName="GetDomains" AutoLoad="True">
<riaControls:DomainDataSource.DomainContext>
<domain:DomainService1/> </riaControls:DomainDataSource.DomainContext>
<riaControls:DomainDataSource.QueryParameters>
<riaControls:Parameter ParameterName="selectedDomain" Value="{Binding Path=SelectedValue,ElementName=cmbDomain}"/> </riaControls:DomainDataSource.QueryParameters>
</riaControls:DomainDataSource>
<StackPanel Orientation="Vertical">
<!--<sdk:DataGrid x:Name="domainGrid" ItemsSource="{Binding Data, ElementName=source}" Height="200" Width="200"/>-->
<sdk:Label Content="Domain"/>
<ComboBox x:Name="cmbDomain" ItemsSource="{Binding Data,ElementName=source}" DisplayMemberPath="Title" Height="50" Width="100"></ComboBox>
<sdk:Label Content="Sub Domain"/>
<ComboBox x:Name="cmbSubDomain" ItemsSource="{Binding Data,ElementName=SubDomainSource}" DisplayMemberPath="Title" Height="50" Width="100"></ComboBox>
</StackPanel>
 if any one help it could be a great support for me .
Srilatha

Answer 1

You can't use overloads.
You need to rename one of your GetDomains:
public IQueryable<Domain> GetDomains()
return this.ObjectContext.Domains;
//for subdomain based on selected value in Domain
public IQueryable<Domain> GetDomains(string selectedDomain)
return this.ObjectContext.Domains.Where(x => x.Title.ToUpper() == selectedDomain.ToUpper());
from
https://msdn.microsoft.com/en-us/library/ee707366%28v=vs.91%29.aspx?f=255&MSPPError=-2147217396
General Rules for using Inheritance            
The following rules apply to using inheritance with RIA Services.
Inheritance is supported only for entity types. Non-entity types are treated as the type specified in the domain service operation signature.
Interface types are not supported for return values or parameters in domain service operations.
The set of types in an inheritance hierarchy must be known at the time of code generation. The behavior for returning a type not specified at the time of code generation is unspecified and implementation-dependent.
The virtual modifier on public properties and fields for an entity type is permitted but ignored when generating the corresponding entity type on the client.
Method overloads for domain service operations are not permitted.
The new (C#) and Shadows (Visual Basic) keywords on public properties are not allowed on entity types and will result in an error when client code is generated.
LINQ query capabilities related to inheritance cannot be translated for execution of domain service methods. Specifically,
OfType<T>, is,
as, and GetType() operators and methods are not supported.  However, these operators may be used directly against
EntitySet or
EntityCollection<TEntity> in LINQ to Objects queries.
Hope that helps.
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