Andy Burns’ SharePoint Blog

So, you’ve created a new custom Field (or column) type, but you don’t want it to be available to add directly to Lists and Libraries – that is, you want to force users to create columns as Site Columns, and add those to the list. Conversely, maybe you want to prevent a column being created as a Site column, and only available to add directly to lists (though I can’t thinik why).

Well, it turns out that that is possible. In the CAML defining your field in fldtypes_???.xml, you can have something like the following:

<FieldTypes>
    <FieldType>
        <Field Name="TypeName">MyCustomField</Field>
        <Field Name="ParentType">MultiChoice</Field>
        <Field Name="TypeDisplayName">My Custom Field</Field>
        <Field Name="ShowOnColumnTemplateCreate">TRUE</Field>
        <Field Name="ShowOnListCreate">FALSE</Field>
        <Field Name="ShowOnDocumentLibraryCreate">FALSE</Field>
        <Field Name="ShowOnSurveyCreate">FALSE</Field>       
        <Field Name="Sortable">FALSE</Field>
        <Field Name="Filterable">TRUE</Field>
        <Field Name="ShowInEditForm">FALSE</Field>
        <Field Name="UserCreatable">TRUE</Field>

ShowOnColumnTemplateCreate controls visibility as a Site Column type. The other ‘Show On X’ values control visibility as a List Column Type for different types of List. You could, therefore, have a Column Type that can only be used on, say, Document Libraries. Hope that helps.

Tags: CAML, SPField

This is a seemingly simple task – given a List or Library in SharePoint, how do I get it’s URL? The difficulty here is that a List has multiple URLs – one for each View on the list. We can get those URLs, but sometimes you really just want the URL to the list, without the /forms/something.aspx bit too.

For example, you might want http://server/siteCollection/site/lists/somelist . If you entered this URL, you’d be taken to the default View for the list, so you don’t really need the extra /forms/… bit to identify the list – that’s all about identifying the view.

Sadly, though, there is no SPList.Url property or equivalent on the SPList object. So, how can I get a list’s URL? Read more »

Tags: Alternate Access Mappings, Navigation, SPList

I had a requirement recently to display the fields of a SharePoint item in another SharePoint site. Now, you can do this with things like the Content Query Web Part, or Data View Web Part, but I was doing a few other things, and specifically, I needed to pull the  fields to display from a particular View on the list.

This turned out to be quite an interesting problem. All fields use a subclass of BaseFieldControl, and this is what renders the field – so it appeared to be fairly straight forward. As always, though, there was a little kink to it – you need an SPContext for the site the item comes from, and you need to use this as the contexts for the SPField‘s rendering control:

SPContext ctx = SPContext.GetContext(HttpContext.Current, item.ID, relatedList.ID, relatedWeb);

SPView relatedView = list.DefaultView;

foreach (string vf in relatedView.ViewFields)
{
    SPField fld = relatedList.Fields.GetFieldByInternalName(vf);

    HtmlGenericControl titleLabel = new HtmlGenericControl("H3");
    titleLabel.InnerText = fld.Title;
    this.Controls.Add( titleLabel );

    BaseFieldControl ctl = fld.FieldRenderingControl;
    ctl.ControlMode = SPControlMode.Display;
    ctl.ListId = relatedList.ID;
    ctl.ItemId = item.ID;
    ctl.RenderContext = ctx;
    ctl.ItemContext = ctx;
    ctl.FieldName = fld.Title;
    ctl.ID = Guid.NewGuid().ToString();
   
    this.Controls.Add( ctl );
}

Groovy!

Tags: SPContext, SPField, SPListItem, Web Parts

This is a bit of a reminder for myself, but quite a lot of the URLs you deal with in SharePoint development are relative – that is, something like an SPList.DefaultViewURL might be:

/sites/web/lists/list/allitems.aspx

That’s fine … but sometimes you need a full absolute URL. For example, you might be sending out an email with a hyperlink in it – a relative URL ain’t going to cut it.

Fortunately, there is a very useful function – SPSite.MakeFullUrl() :

Returns the full URL for the specified server-relative URL.

That’s great – but it raises some questions. What about Alternate Access Maps? What URL would be returned? Well, predictably, the URL used in the SPSite Constructor in the first place. Mostly, they either accept a URL (which defines a zone), or they accept a GUID and an SPUrlZone value. There is a constructor that just accepts a GUID – which will then use the default zone. Similarly, the constructor accepting a GUID and SPUserToken also uses the Default Zone.

(If you open it up in reflector, you can see it just calling a private constructor passing the SPUrlZone.Default value).

Tags: Alternate Access Mappings, SPSite

I’ve been working on a custom field for, well, a while now, and after making some changes I started to get the error “To save to the server, correct the invalid or missing required properties” when trying to edit a document and save the changes back in Word 2007. This was a little strange, as I’d already sorted out hiding the custom field from the document information panel, and things had been working fine since then.

New documents seemed to be alright, but the older ones weren’t. So, maybe the problems were all the old documents, rather than my field.

Eventually, I came across this knowledgebase article – so I “inspected” the document, removed any of it’s custom data, and resaved it – and it worked fine.

What I think happened here was, I was testing different settings for Content Approval and Versioning on my document libraries. I think the troublesome documents were created when one of those was set to be ‘on’, and I subsequently turned it ‘off’. This meant that the document actually had extra data that referred to a column that no longer existed (I think) – which probably means this is related to Content Approval.

But I’d be curious if anyone else has managed to cause this error, and how they did so.

Tags: Content Approval, Document Templates, SPField, Versions

So, I’m working on a custom field definition for SharePoint. My field has a few custom properties that you need to fill in when you create it. However, after creation, those fields were empty – they were simply never set. You could then update them, and that worked fine, but creation was broken.

The code I’d inherited was trying to solve this problem (it’s a known issue) this way - which is a bit ugly. It also holds memory for the Dictionary of values that, as far as I could see, was only being freed on IISReset. Yuck. And it didn’t work in our code, despite matching the example in that thread quite closely.

Fortunately, I came across a neat post on Gunnar Peipman’s blog – Temporary Solution for GetCustomProperty an SetCustomProperty Errors. I don’t like using reflection to invoke the methods I need to use, but at least it’s a solution, even if not ideal. And it works!

Please go to Gunnar’s post – but just in case his blog goes down, I’m going to shamelessly plagiarise his code below…

Thanks Gunnar! Read more »

Tags: SPField

In SharePoint, Event Handlers (or Event Receivers – whichever terminology, a child of SPItemEventReceiver) can be registered against lists/libraries. You can do this through an SPWeb (site) scoped feature, declaratively or programmatically with an SPEventReceiverDefinition.

Unfortunately, you can’t declaratively register event receivers at the SPSite (Site collection) level – which would be fantastic – just turn on the feature and across all your site collection lists/libraries of a give type would get additional event receivers. Personally, I think this may be a bug; I don’t see why this shouldn’t work at the SPSite level.

Anyway, there is still another option – we could register our event against a particular Content Type. This is a less often used approach, which raises two questions – how do you do it, and what happens to child Content Types? Read more »

Tags: Event Receivers, SPContentType, SPFeatureReceiver, SPItemEventReceiver

Okay, this is weird.

I’m trying to do something with various types of item, including Blog Posts, in SharePoint. Naturally, I’m getting the SPListItem for them, and then the SPListItem.ContentType, so I can check what kind of item is it. The weird thing is, if I try to get a Blog Post, the SPListItem.ContentType is NULL. Read more »

Tags: Blogs, Content Type, SPContentType, SPListItem

So, I’ve been working with a custom field type recently. It’s quite a complicated one – I’ll not go into details – but we did hit a problem with it. When a Word document was opened it would try to display our field in the Document Information Panel, which isn’t really possible, and caused Word to die in a horrible fashion. I forget the exact error we were getting, but it was something to do with the XSN being invalid.

What we really needed was a way to set that the property wasn’t to be shown in the Document Information Panel. However, there is no easy way of doing this with a purely programmatically created column. There are properties on the SPField object that can be accessed programmatically, and the CAML for a FieldRef can set ShowInFileDlg – but there isn’t an obvious way to set this value from C# code.

Naturally, that’s what we wanted to do. Well, there is a combination approach – the SPField.SchemaXml property allows us to get/set the CAML that defines the field.

So, I came up with this static function:

static void SetShowInFileDlg(SPField f, bool value)
        {
            XmlDocument fieldSchemaXml = new XmlDocument();
            fieldSchemaXml.LoadXml(f.SchemaXml);
            XmlAttribute attr = fieldSchemaXml.CreateAttribute("ShowInFileDlg");
            attr.Value = value.ToString().ToUpper();
            XmlNode fieldXmlNode = fieldSchemaXml.SelectSingleNode("Field");
            XmlAttributeCollection fieldAttributes = fieldXmlNode.Attributes;
            fieldAttributes.Append(attr);
           
            f.SchemaXml = fieldXmlNode.OuterXml;
            f.Update(true);
        }

I’m not sure what happens if you’re trying to update an already widely used column – will it update all content types that that column – but this worked for us.

Tags: Document Information Panel, SPField, xml

Previously I’ve blogged about using ddwrt to format dates and datetimes. Well, today, I found myself trying to figure it out again, so here is a reminder. Remember, one of the big advantages of this (in the UK at least, where we are UTC time half the year) is that the DateFormat function accounts for daylight savings (i.e. the difference between GMT and BST)

Add this to the xsl:stylesheet tag at the top:

xmlns:ddwrt="http://schemas.microsoft.com/WebParts/v2/DataView/runtime"

Then you can use something like the following (where item_date is an XSL variable with our date in it):

<xsl:value-of select="ddwrt:FormatDate(string($item_date), 2057, 15)" />

Here the FormatDate function is taking the string of the date, formating it for Great Britain’s locale (2057), and specifying an output format (15). Output formats vary by locale, and not all seem to be valid. I found that when I tried a format of ’2′, for example, that I got an XSL error.

This is a particularly useful with the Content Query Web Part and the RSS Feed Web Part

Tags: Dates, XSL