LinqToCRM does not cast properly

I want to change all my queries from QueryExpression to Linq. In development time, all seems to be just fine, but I always get a cast exception at runtime (can't cast Microsoft.xrm.sdk.entity to Xrm.SystemUser -> Xrm is the early bound classes generated with CrmSvcUtil).

        var context = new OrganizationServiceContext(crmService);
        SystemUser x = (from c in context.CreateQuery<SystemUser>()
                where c.DomainName == @"pfgc\" + Environment.UserName
                select c).FirstOrDefault();

This code is straightforward. I've even tried without the Where clause and it won't change anything.

I tried the following (no FirstOrDefault and var instead of SystemUser)

            var x = (from c in context.CreateQuery<SystemUser>()
                where c.DomainName == @"pfgc\" + Environment.UserName
                select c);

This won't throw an exception but x type is Microsoft.xrm.sdk.linq.Query. What am I doing wrong? It seems to be exactly what the开发者_JAVA百科 SDK suggests to do.

EDIT:

GCATNM has the right answer. In case someone faces the same issue, here's a sample of the working code:

    public SystemUser GetCurrentUser()
    {
        var context = GetOrgContext();
        return (from c in context.CreateQuery<SystemUser>()
                where c.DomainName == @"pfgc\" + Environment.UserName
                select c).FirstOrDefault();
    }

    public OrganizationServiceContext GetOrgContext()
    {
        var serviceProxy1 = new OrganizationServiceProxy(organizationUri, homeRealmUri, credentials, null);
        serviceProxy1.ServiceConfiguration.CurrentServiceEndpoint.Behaviors.Add(new ProxyTypesBehavior());
        return new OrganizationServiceContext(serviceProxy1);
    }

I had a similar problem with LINQ-to-CRM and went back to QueryExpressions because they worked, until I found the solution in some SDK sample while looking for something else: You need to add a ProxyTypesBehavior to your IOrganizationService object. I don't know what it does, but that definitely was the change that allowed me to use LINQ with the early bound classes (as I perceive it, LINQ-to-CRM can only be used with the early bound classes).

So the line you need after creating your IOrganizationService is:

organizationService.ServiceConfiguration.CurrentServiceEndpoint.Behaviors.Add(new ProxyTypesBehavior());

I hope that helps.

It returns an Entity object, so you'll need to call ToEntity() if you want a System User object. The following should work for you:

var context = new OrganizationServiceContext(crmService);
    SystemUser x = (from c in context.CreateQuery<SystemUser>()
            where (string)c["DomainName"] == @"pfgc\" + Environment.UserName
            select c).FirstOrDefault().ToEntity<SystemUser>();