How to check membership from current user and set readonly of some fields when override ListFieldIterator?

Question

I have created a custom ListForm template and overide the ListFieldIterator.

I have for example 10 fields in my content type. 5 of these 10 fields must be shown for the creator of the item. The other 5 must be exluded. So I need to check if this is a new item and not an exiting item.

Step 2, we need to check if the item is existing, and the user is going to edit it, I would like to check if the user is member of an custom usergroup. If it is member of this usergroup, I would like to show all the fields and exlude 0 fields. Otherwise, if the user is not a member of the usergroup I would like to show all the 10 fields, but 5 of the 10 fields need to be readonly.

public class CustomListFieldIterator : ListFieldIterator
{
    protected override bool IsFieldExcluded(SPField field)
    {
        if(this is an new item)
        {
            // show only 5 fields
        }
        else
        {
            // this is an existing item, you are editing this item
            // check if the current user is member of an custom usergroup "Auditors"
            SPWeb site = SPContext.Current.Web;
            int groupId = site.Groups["Auditors"].ID;
            if (site.IsCurrentUserMemberOfGroup(groupId))
            {
                // show all the fields
                return false;
            }
            else
            {
                // show all the fields, but 5 of the 10 fields READONLY
            }
        }
    }
}

I defined my custom contenttype as follow with a reference to my custom listForm template:

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <!-- Parent ContentType: Item (0x01) -->
  <ContentType ID="0x0100839f032740084ac2ae6ea6ab45928a65"
               Name="MyCustomContentType"
               Group="MyCustomContentType"
               Description="MyCustomContentType"
               Inherits="FALSE"
               Version="0">
    <FieldRefs>

      <!-- These are 5 fields always visible-->
      <!-- Everybody is enabled to edit these fields -->
      <FieldRef ID="{EBC17A5D-F320-43D0-A275-7C657EA6F6C9}" Name="RFCDescription"  ShowInEditForm="TRUE" ShowInNewForm="TRUE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{76BF7D5B-6A12-48D1-9827-ADE990B03216}" Name="RFCCompany"  ShowInEditForm="TRUE" ShowInNewForm="TRUE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{9C9ED55A-7025-47F4-9637-27D5D2A1BCAE}" Name="RFCDepartment" ShowInEditForm="TRUE" ShowInNewForm="TRUE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{87DA58EB-3C70-4EF4-B833-1D4A93D60AC9}" Name="RFCClient"  ShowInEditForm="TRUE" ShowInNewForm="TRUE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{56398822-7A4F-4155-A875-ADD09F32D4F2}" Name="RFCContact"  ShowInEditForm="TRUE" ShowInNewForm="TRUE" ShowInDisplayForm="TRUE"/>


      <!-- These are 5 fields only visible in edit mode -->
      <!-- only users in usergroup "Auditors" may change these fields, otherwise readonly -->
      <FieldRef ID="{1A64CE4A-716C-4572-B344-E7CCFE443D50}" Name="RFCScope"  ShowInEditForm="TRUE" ShowInNewForm="FALSE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{39BC744E-08D4-410C-9D66-B728221634F5}" Name="RFCOperatingCosts"  ShowInEditForm="TRUE" ShowInNewForm="FALSE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{09B7ED41-C5D0-4B8F-B102-F698164A05B9}" Name="RFCExpertise"  ShowInEditForm="TRUE" ShowInNewForm="FALSE" ShowInDisplayForm="FALSE"/>
      <FieldRef ID="{C95F5617-0C01-49F2-AA5C-8ADE757901F4}" Name="RFCPriority"  ShowInEditForm="TRUE" ShowInNewForm="FALSE" ShowInDisplayForm="TRUE"/>
      <FieldRef ID="{D6E32A83-D6FD-431B-B2CB-625516D3935F}" Name="RFCDatePlanned"  ShowInEditForm="TRUE" ShowInNewForm="FALSE" ShowInDisplayForm="TRUE"/>

<FieldRef ID="{427E04A8-45E5-4243-BFE9-5FDF6FC6205B}" Name="RFCState" ShowInEditForm="TRUE" ShowInNewForm="FALSE" ShowInDisplayForm="TRUE"/>

    </FieldRefs>

    <XmlDocuments>
      <XmlDocument NamespaceURI="http://schemas.microsoft.com/sharepoint/v3/contenttype/forms">
        <FormTemplates  xmlns="http://schemas.microsoft.com/sharepoint/v3/contenttype/forms">
          <Display>MyCustomListFormTemplate</Display>
          <Edit>MyCustomListFormTemplate</Edit>
          <New>MyCustomListFormTemplate</New>
        </FormTemplates>
      </XmlDocument>
    </XmlDocuments>

  </ContentType>
</Elements>

I have implemted 5 fields will be visible in new and edit mode. The other 5 fields will be only visible in edit mode.

Answer 1

You can set display in new/edit form property of field to FALSE in the list schema and then add asp controls for these fields to you custom form template. After this you should override

OnSaveContext SPContext.Current.FormContext.OnSaveHandler += OnItemSaved;

In OnItemSaved handler you can collect data from controls and fill item fields.

Answer 2

You have 2 different problems here (plus that it also matters where you use this code).

SPWeb site = SPContext.Current.Web;

To check if A CERTAING user is member of a certain group:

SPGroup managerGroup = site.Groups["ReplaceWithGroupName"];
bool isManager = site.IsCurrentUserMemberOfGroup(managerGroup);

and for the Current user is easier

SPWeb web = // ...
SPGroup group = web.SiteGroups["GroupName"];
if (group.ContainsCurrentUser)
{
  // your code here to hide fields
}

For the 2nd part however SharePoint does not provide the capability to hide FIELDS per Request/User, etc. - you hide them - is for everyone, so updating Fields Visibility is not a solution for you in such situation.

I would go for an easier solution more maintainable solution, that would rely on injecting Javascript in the actual page (via SPD) or a CEWP to control the rendering of fields, by disabling/hiding controls. It is possible to detect in which group the user is part of using details here http://social.technet.microsoft.com/forums/en-ZA/sharepointdevelopmentprevious/thread/dee33fe3-a067-455a-aa65-3bc9bab2e761

Answer 3

It can be done, but you need to override CreateChildControls in addition to IsFieldExcluded.

Here is a full code for your custom list field iterator:

public class CustomListFieldIterator : ListFieldIterator
{
    protected override void CreateChildControls()
    {
        this.Controls.Clear();
        if (this.ControlTemplate == null)
        {
            throw new ArgumentException("Could not find ListFieldIterator control template.");
        }
        for (int i = 0; i < base.Fields.Count; i++)
        {
            SPField field = base.Fields[i];
            if (!this.IsFieldExcluded(field))
            {
                var child = new CompositeField();
                child.ControlMode = base.ControlMode;
                child.FieldName = field.InternalName;
                var auditors = SPContext.Current.Web.Groups["Auditors"].ID;
                bool isAuditor = SPContext.Current.Web.IsCurrentUserMemberOfGroup(auditors);

                //if field is "Title", we in edit mode and user is not Auditor, make field readonly
                if (field.InternalName.Equals("Title") && ControlMode == SPControlMode.Edit && !isAuditor)
                {
                    child.ControlMode = SPControlMode.Display;
                }
                this.Controls.Add(new LiteralControl("<tr>"));
                this.Controls.Add(child);
                Controls.Add(new LiteralControl("</tr>"));
            }
        }

    }

    protected override bool IsFieldExcluded(SPField field)
    {
        if (base.IsFieldExcluded(field))
        {
            return true;
        }
        //exclude field "Title" in new mode
        if (base.ControlMode == SPControlMode.New)
        {
            if (field.InternalName.Equals("Title"))
            {
                return true;
            }
        }
        return false;
    }
}

Some explanation:
- Field "Title" excluded in a new mode for all users.
- In edit mode field "Title" set as read only for all users, excepts "Auditors" group members.

I have to made a little trick with overriding CreateChildControls to insert on page CompositeField with different ControlMode depending on group membership. CompositeField is actually a control, which render CompositeField rendering template (you can find it in DefaultTemplates.ascx).

So, this can be done without javascript.
Feel free to ask any questions.