How do I read LookUp fields with multiple values in SharePoint?
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28-10-2019 - |
Вопрос
Hi and thanks for looking!
Background
I have inherited an old .NET project based on SharePoint 2007 and have designed and external core library which merely accesses SP data, therefore making SP just a backend. Yes, I know it would be better to migrate to SQL, but the client doesn't agree.
The previous developers used a simple read method to read the data in a SP list:
SPList list = CurrentRootWeb.Lists["SomeListName"];
And then they access list properties through a dictionary of sorts (i.e. for each item in list, get item["SomeValue"]).
I am not skilled in SharePoint, so I don't know if this is the most efficient manner to go about accessing it's data.
Problem
How do I read LookUp fields with multiple values in SharePoint?
Every property they request seems to want a string in return. So item[SomeString]
is okay, but item[SomeList]
makes everything barf! I would have thought that a multi-value lookup list column comes in as a serialized or delimited string holding the selected values (example: "red;blue;green"). What am I missing?
Thanks!
Решение
For each of the SPField
s in the list's fields, you need to test the field's Type
.
If the type is SPFieldType.MultiChoice
, then you cast the SPField
to SPFieldChoice
and access the Choices
collection, which is a StringCollection
.
Другие советы
If you are specifically interested in LookUp fields with multiple values not just MultiChoice feilds, then following code should help:
item.Fields["LookFieldName"].Type == SPFieldType.Lookup;
SPFieldLookup LookUpField = item.Fields["LookFieldName"] as SPFieldLookup;
if (LookUpField.AllowMultipleValues)
{
SPFieldLookupValueCollection valueCollection = item[Field.Id] as SPFieldLookupValueCollection;
string[] arrLookupValues = (from SPFieldLookupValue val in valueCollection select val.LookupValue).ToArray<string>();
}