The given key is not present in the dictionary - dynamics-crm-2011

Question

Hi I am trying to fetch the accounts from CRM 2011. I am fetching the data in the EntityCollection . But when I am trying to read or access data from entityCollection it displayed first record but throwing an error after that record. Kindly have a look to below code and suggest me.
string fetch2 = #"
<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='false'>
<entity name='account'>
<attribute name='name' />
<attribute name='address1_city' />
<attribute name='primarycontactid' />
<attribute name='telephone1' />
<attribute name='accountid' />
<order attribute='name' descending='false' />
<filter type='and'>
<condition attribute='accounttype' operator='eq' value='01' />
</filter>
</entity>
</fetch>";
try
{
EntityCollection fxResult = _service.RetrieveMultiple(new FetchExpression(fetch2));
foreach (var e in fxResult.Entities)
{
Console.WriteLine("Id:{0},Name:{1},City:{2}", e.Attributes ["accountid"].ToString(), e.Attributes["name"].ToString(), e.Attributes["address1_city"].ToString());
// Console.WriteLine("Id:{0},Name:{1},City:{2}", e.ToEntity["accountid"]);
}
}
catch (Exception e)
{
Console.WriteLine("Error:==" + e.Message);
}

Answer 1

Before access an attribute you need to ask if it is in the context:
e.Attributes.Contains("address1_city")
If the collection contains the attribute, then you can access it safe.
string accountid = (string)e.Attributes["address1_city"]
The reason the attribute doesn't come in the collection it's because it is null or you are not retrieving it. In this case maybe, one of your attributes is null. Maybe address1_city.

Answer 2

When retrieving attribute values of late-bound Entity objects, the recommended approach is to use method getAttributeValue<T>. When the attribute is not present in the entity's attribute collection, it returns default(T).
The primary key ('id') of the record is always present when it is returned by the OrganizationService.
So your code should look like this:
EntityCollection fxResult = _service.RetrieveMultiple(new FetchExpression(fetch2));
foreach (var e in fxResult.Entities)
{
Console.WriteLine(
"Id:{0},Name:{1},City:{2}",
e.Id,
e.GetAttributeValue<string>("name"),
e.GetAttributeValue<string>("address1_city"));
}
You can safely use the item selector when you need to assign a value to an attribute, regardless if it is already present or not.
E.g. the following code line is valid:
e["name"] = "Demo Accountname";