Dynamically specifying lambda function parameters

Question

Suppose I have the following line of code:

context.Load(itemCollection, item => item.Include(i => i["Title"], i => i["Name"]));

Is there any way I can dynamically specify the parameters to the item.Include() function instead of hard-coding them as above?

I would ideally like to allow users to select properties they want to retrieve of an object such as Title, Name, Description, etc.

FYI, here is the ClientContext.Load function. This function is coming from Microsoft.SharePoint.Client.dll

public void Load<T>(T clientObject, params Expression<Func<T, object>>[] retrievals) where T : ClientObject
{
  if ((object) clientObject == null)
    throw new ArgumentNullException("clientObject");
  ClientAction.CheckActionParameterInContext(this, (object) clientObject);
  DataRetrieval.Load<T>(clientObject, retrievals);
}

yes, I make functions like this for MS CRM libraries all the time. You want to investigate `public void MyMethod(Func> expression) where t : ` extending the type you want in the expression. Anyway, search on Func for more examples — Mike_Matthews_II, Mar 13 '13 at 00:53

score 2 · Answer 1 · edited Apr 25 '13 at 11:06

2

I don't have the necessary setup to test it, but will something like this work?

String[] keys = ...;
context.Load(   itemCollection
              , item => item
                        .Include(keys
                        .Select(key => { i => i[key] })
                        .ToArray()
            );

edited Apr 25 '13 at 11:06

Gennady Vanin Геннадий Ванин

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answered Mar 13 '13 at 00:47

bmm6o

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No. We don't know how many keys (properties) the user wants to retrieve. – Moon Mar 13 '13 at 00:49
What are the signatures of the context.Load() and item.Include() functions? – bmm6o Mar 13 '13 at 00:51
Updated my question with the info you requested. – Moon Mar 13 '13 at 00:59

score 0 · Answer 2 · edited May 23 '17 at 12:28

0

Have a look at the Answer for this question.
I had a similar problem with creating dynamic where clauses, and this is how I got around it.

edited May 23 '17 at 12:28

Community

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answered Mar 13 '13 at 00:26

Heinrich

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score 0 · Answer 3 · answered Mar 14 '13 at 23:19

Use the following syntaxt (works in JavaScript, but haven't tested it in C#):

context.load(this.list, 'Include(Title, Name)');

'Include(Title, Name)' is a string and is easier to generate based on user input.

this.list refers to a sharepoint list that is loaded before.

Dynamically specifying lambda function parameters

3 Answers3