To download this web part as a compiled WSP package, or for more information, click here:

public class AssignedToMe : System.Web.UI.WebControls.WebParts.WebPart
{
    protected override void Render(System.Web.UI.HtmlTextWriter writer)
    {
        // Controls are made in Render() rather than 
        // CreateChildControls() because the TBODY
        // tag does not appear to exist in the Web.UI
        // namespace and it is required for the SharePoint
        // expander javascript to work

        SPWeb spWebThis = SPControl.GetContextWeb(this.Context);

        List<SPWeb> webs = new List<SPWeb>();
        PopulateWebCollectionRecursive(webs, spWebThis);

        #region Create table and header rows
        Table table = new Table();
        this.Controls.Add(table);
        table.Attributes["class"] = "ms-settingsframe";
        table.Width = Unit.Percentage(100);
        table.BorderStyle = BorderStyle.None;
        table.CellPadding = 1;
        table.CellSpacing = 0;
        table.Style.Add("border-top", "0px solid");

        TableRow rowHeader = new TableRow();
        table.Rows.Add(rowHeader);

        TableCell cellHeaderTitle = new TableCell();
        rowHeader.Cells.Add(cellHeaderTitle);
        cellHeaderTitle.Wrap = false;
        cellHeaderTitle.Attributes["class"] = "ms-vh2-nofilter";
        cellHeaderTitle.Attributes["scope"] = "col";
        cellHeaderTitle.Text = "Item";

        TableCell cellHeaderModified = new TableCell();
        rowHeader.Cells.Add(cellHeaderModified);
        cellHeaderModified.Wrap = false;
        cellHeaderModified.Attributes["class"] = "ms-vh2-nofilter";
        cellHeaderModified.Attributes["scope"] = "col";
        cellHeaderModified.Text = "Modified";

        TableCell cellHeaderModifiedBy = new TableCell();
        rowHeader.Cells.Add(cellHeaderModifiedBy);
        cellHeaderModifiedBy.Wrap = false;
        cellHeaderModifiedBy.Attributes["class"] = "ms-vh2-nofilter";
        cellHeaderModifiedBy.Attributes["scope"] = "col";
        cellHeaderModifiedBy.Text = "Modified By";

        TableCell cellHeaderList = new TableCell();
        rowHeader.Cells.Add(cellHeaderList);
        cellHeaderList.Wrap = false;
        cellHeaderList.Attributes["class"] = "ms-vh2-nofilter";
        cellHeaderList.Attributes["scope"] = "col";
        cellHeaderList.Text = "List";

        TableCell cellHeaderSite = new TableCell();
        rowHeader.Cells.Add(cellHeaderSite);
        cellHeaderSite.Wrap = false;
        cellHeaderSite.Attributes["class"] = "ms-vh2-nofilter";
        cellHeaderSite.Attributes["scope"] = "col";
        cellHeaderSite.Text = "Site";

        table.RenderBeginTag(writer);
        rowHeader.RenderControl(writer);
        #endregion

        int count = 0;
        string rowClass = "";

        int listIndex = 0;
        foreach (SPWeb spWeb in webs)
        {
            foreach (SPList spList in spWeb.Lists)
            {
                try
                {
                    SPField spFieldAssignedTo = spList.Fields.GetFieldByInternalName("AssignedTo");
                    if (spFieldAssignedTo == null)
                        throw new Exception();
                }
                catch
                {
                    continue;
                }

                SPQuery spQuery = new SPQuery();

                spQuery.Query = String.Format(
                    "<Where><Eq><FieldRef Name='{0}' LookupId='TRUE' /><Value Type='User'>{1}"
                    + "</Value></Eq></Where>",
                    "AssignedTo",
                    spWebThis.CurrentUser.ID.ToString());

                SPListItemCollection spListItemCollection = spList.GetItems(spQuery);

                if (spListItemCollection.Count > 0)
                {
                    listIndex++;

                    // This is a (messy) replication of the code used
                    // by SharePoint's expanding/collapsing list viewer 
                    LiteralControl headerLiteral = new LiteralControl(String.Format(
                        "<TBODY id=\"titl{0}_\" groupString=\"\"><TR><TD colspan=\"100\" class=\"ms-gb\""
                        + " style=\"border-bottom: 0; border-top: 0;\" nowrap>"
                        + "<img src=\"/_layouts/images/blank.gif\" alt=\"\" height=1 width=0>"
                        + "<a href=\"javascript:\" onclick=\"javascript:ExpCollGroup('{0}_','img_{0}_');"
                        + "return false;\">"
                        + "<img id=\"img_{0}_\" src=\"/_layouts/images/plus.gif\" alt=\"Expand/Collapse\""
                        + " border=\"0\"></a>&nbsp;"
                        + "<a href=\"javascript:\" onclick=\"javascript:ExpCollGroup('{0}_','img_{0}_');"
                        + "return false;\">"
                        + "{1}</a>&nbsp;({2})</TD></TR></TBODY><TBODY id=\"tbod{0}__\""
                        + " style=\"display: none;\" isLoaded=\"true\">",
                        "1-" + listIndex,
                        spList.Title,
                        spListItemCollection.Count));

                    headerLiteral.RenderControl(writer);

                    int item = 0;
                    foreach (SPListItem spListItem in spListItemCollection)
                    {
                        #region Create controls for basic item information
                        TableRow rowItem = new TableRow();
                        rowItem.Attributes["class"] = rowClass;
                        table.Rows.Add(rowItem);

                        TableCell cellItemTitle = new TableCell();
                        rowItem.Cells.Add(cellItemTitle);
                        cellItemTitle.Attributes["class"] = "ms-vb2";
                        cellItemTitle.VerticalAlign = VerticalAlign.Top;

                        HyperLink anchorItemTitle = new HyperLink();
                        cellItemTitle.Controls.Add(anchorItemTitle);
                        anchorItemTitle.NavigateUrl = spList.Forms[PAGETYPE.PAGE_DISPLAYFORM]
                            .ServerRelativeUrl + "?ID=" + spListItem.ID;
                        string strItemName = "";

                        SPField fieldTitle = spListItem.Fields.GetFieldByInternalName("Title");
                        strItemName = fieldTitle.GetFieldValueAsText(spListItem[fieldTitle.Id]);

                        if (strItemName == null || strItemName.Trim().Length == 0)
                            strItemName = "(No title)";
                        anchorItemTitle.Text = strItemName;

                        TableCell cellItemModified = new TableCell();
                        rowItem.Cells.Add(cellItemModified);
                        cellItemModified.Attributes["class"] = "ms-vb2";
                        cellItemModified.Wrap = false;
                        cellItemModified.VerticalAlign = VerticalAlign.Top;

                        SPField fieldModified = spListItem.Fields.GetFieldByInternalName("Modified");
                        cellItemModified.Text = fieldModified.GetFieldValueAsText(
                            spListItem[fieldModified.Id]);

                        TableCell cellItemModifiedBy = new TableCell();
                        rowItem.Cells.Add(cellItemModifiedBy);
                        cellItemModifiedBy.Attributes["class"] = "ms-vb2";
                        cellItemModifiedBy.Wrap = false;
                        cellItemModifiedBy.VerticalAlign = VerticalAlign.Top;

                        SPField fieldModifiedBy = spListItem.Fields.GetFieldByInternalName("Editor");
                        cellItemModifiedBy.Text = fieldModifiedBy.GetFieldValueAsHtml(
                            spListItem[fieldModifiedBy.Id]);

                        TableCell cellItemList = new TableCell();
                        rowItem.Cells.Add(cellItemList);
                        cellItemList.Attributes["class"] = "ms-vb2";
                        cellItemList.Wrap = false;
                        cellItemList.VerticalAlign = VerticalAlign.Top;

                        HyperLink anchorList = new HyperLink();
                        cellItemList.Controls.Add(anchorList);
                        anchorList.NavigateUrl = spList.Forms[PAGETYPE.PAGE_DISPLAYFORM].ServerRelativeUrl;
                        anchorList.Text = spList.Title;

                        TableCell cellItemSite = new TableCell();
                        rowItem.Cells.Add(cellItemSite);
                        cellItemSite.Attributes["class"] = "ms-vb2";
                        cellItemSite.Wrap = false;
                        cellItemSite.VerticalAlign = VerticalAlign.Top;

                        HyperLink anchorWeb = new HyperLink();
                        cellItemSite.Controls.Add(anchorWeb);
                        anchorWeb.NavigateUrl = spWeb.ServerRelativeUrl;
                        anchorWeb.Text = spWeb.Title;

                        rowItem.RenderControl(writer);
                        #endregion

                        rowClass = (rowClass == "") ? "ms-alternating" : "";
                        count++;
                        item++;
                    }

                    TableRow rowSpacer = new TableRow();
                    table.Rows.Add(rowSpacer);

                    TableCell cellSpacer = new TableCell();
                    cellSpacer.ColumnSpan = table.Rows.Count;
                    cellSpacer.Text = "<img src=\"/_layouts/images/blank.gif\" alt=\"\" height=10 width=0>";
                    rowSpacer.Cells.Add(cellSpacer);

                    rowSpacer.RenderControl(writer);

                    LiteralControl footerLiteral = new LiteralControl(String.Format(
                        "</TBODY><TBODY id=\"foot{0}__\"></TBODY>",
                        "1-" + listIndex));

                    footerLiteral.RenderControl(writer);
                }
            }
        }

        if (count == 0)
        {
            #region Create controls for 'no items'
            TableRow rowItemNone = new TableRow();
            table.Rows.Add(rowItemNone);

            TableCell cellItemNone = new TableCell();
            rowItemNone.Cells.Add(cellItemNone);
            cellItemNone.ColumnSpan = table.Rows.Count;
            cellItemNone.Attributes["class"] = "ms-propertysheet";
            cellItemNone.VerticalAlign = VerticalAlign.Top;
            cellItemNone.Style.Add("padding-left", "5px");
            cellItemNone.Text = "No items";

            rowItemNone.RenderControl(writer);
            #endregion
        }

        table.RenderEndTag(writer);
    }

    private void PopulateWebCollectionRecursive(List<SPWeb> webs, SPWeb thisWeb)
    {
        webs.Add(thisWeb);

        // Important to use .GetSubwebsForCurrentUser() as opposed
        // to the .Webs collection, as the user may not be privileged
        // to certain webs
        foreach (SPWeb subWeb in thisWeb.GetSubwebsForCurrentUser())
            PopulateWebCollectionRecursive(webs, subWeb);
    }
}

Web Part Page documents are SPListItem objects internally, even though SharePoint makes a distinction between document and list libraries in the user interface. I couldn’t find a path through the object model of finding this SPListItem that my web part instance was a part of. Instead I accessed the item via the current URL and a reference to the context’s SPWeb.

A typical problem with assessing permissions (or roles) for a non-administrative user is that SharePoint savagely denies access to it. Try/catch blocks can be ineffective here, with ASP.NET deciding to redirect to the ‘Access denied’ page. Depending on what you need to do, there are methods involving simple impersonation or more convoluted techniques.

Thankfully I found a peace-loving property .AllRolesForCurrentUser that accurately returns the item-level roles for the current user, regardless of their permissions level.

The resulting function,

    bool IsDesigner()
    {
        SPWeb spWeb = SPControl.GetContextWeb(this.Context);
        string pageUrl = this.Page.Request.Url.AbsolutePath;
        SPListItem spListItem = spWeb.GetListItem(pageUrl);

        foreach (SPRoleDefinition roleDefinition in spListItem.AllRolesForCurrentUser)
        {
            if (roleDefinition.Type == SPRoleType.WebDesigner
                || roleDefinition.Type == SPRoleType.Administrator)
            {
                return true;
            }
        }

        return false;
    }

In design-time it doesn’t so much matter where you place the <xsl:param> tag - SharePoint Designer will render the web part. At run-time, if <xsl:param> tags appear beneath <xsl:variable> tags then SharePoint delivers one of its characteristically unhelpful error messages (shown below). Of course, you try out what it suggests and everything is irritatingly fine in Designer.

There are a few available options to improve the readability of multi-line columns:

1. Make the column name really really long
2. Create a Datasheet view where column size settings are preserved (this option isn’t applicable to users browsing with anything except Internet Explorer)
3. Modify the FLDTYPES.XML file to set a fixed width in HTML
4. Create the same effect as option #3 by employing a new custom field with modified rendering (thus avoiding unrecommended toying with FLDTYPES.XML)

Despite the modification of FLDTYPES.XML being unrecommended and unsupported, I went for option #3. It’s a simple and fairly unimposing change. There are two caveats though:

• This change will force a minimum width on all multi-line text fields on all display modes of all webs on the server
• The change will be lost if WSS is reinstalled, as it is not stored in the database

The code snippet below shows the two lines I added to FLDTYPES.XML to make multi-line text columns display with a minimum width of 300 pixels. Note that the CSS min-width attribute is not applicable in IE, so width is used to similar effect. Don’t forget to restart the IIS server after changes made to FLDTYPES.XML.

    <FieldType>
        <Field Name="TypeName">Note</Field>
        <Field Name="TypeDisplayName">$Resources:core,fldtype_note;</Field>
        <Field Name="InternalType">Note</Field>
        <Field Name="SQLType">ntext</Field>
        <Field Name="ParentType"></Field>
        <Field Name="FieldTypeClass">Microsoft.SharePoint.SPFieldMultiLineText</Field>
        <Field Name="Sortable">FALSE</Field>
        <Field Name="Filterable">FALSE</Field>
        <RenderPattern Name="HeaderPattern">
            <HTML><![CDATA[<div style="width: 300px">]]></HTML>
            <FieldSwitch>
                <Expr><GetVar Name='Filter'/></Expr>
                <Case Value="1">
                    <FieldSwitch>
                        <Expr><Property Select="aggregation"/></Expr>
                        <Case Value="merge">
                            <HTML><![CDATA[<INPUT TYPE="TEXT" MAXLENGTH="256" CLASS="ms-input" ID="diidFilter]]></HTML>
                            <Property Select='Name'/>
                            <HTML><![CDATA[" OnKeyPress='FilterNoteField("]]></HTML>
                            <GetVar Name="View"/>
                            <HTML><![CDATA[",]]></HTML>
                            <ScriptQuote><Property Select='Name' URLEncode="TRUE"/></ScriptQuote>
                            <HTML><![CDATA[,this.value, event.keyCode);' OnChange='FilterNoteField("]]></HTML>
                            <GetVar Name="View"/><HTML><![CDATA[",]]></HTML>
                            <ScriptQuote><Property Select='Name' URLEncode="TRUE"/></ScriptQuote>
                            <HTML><![CDATA[,this.value, 13);'/>]]></HTML>
                            <HTML><![CDATA[<BR>]]></HTML>
                        </Case>
                        <Default/>
                    </FieldSwitch>
                </Case>
                <Default/>
            </FieldSwitch>
            <Property Select="DisplayName" HTMLEncode="TRUE"/>
            <HTML><![CDATA[<IMG SRC="]]></HTML><FieldFilterImageURL/>
            <HTML><![CDATA[" BORDER=0 ALT=]]></HTML><HTML>$Resources:core,550;</HTML>
            <HTML><![CDATA[>]]></HTML>
            <HTML><![CDATA[</div>]]></HTML>
        </RenderPattern>
        ...
    </FieldType>

Cheap energy has been abundantly available for the last century. But is it really as cheap as it seems? Conventional energy trade carries external costs that neither the producer nor the consumer pays. Society at large must foot the bill for negative social and environmental by-products of energy production and consumption. This paper discusses the consequences of the failure to incorporate these externalities into the price of traded energy.

Externalities are defined as benefits or costs generated as an unintended by-product of an economic activity that do not accrue to the parties involved in the activity and where no compensation takes place^[5]. In other words, any party (be it an individual, a group, a society or world-wide) external to an economic transaction may receive positive or negative impacts to which they had no intention or input in accruing.

Figure 1 illustrates the transactions involved in a voluntary economic exchange where externalities are present. An external cost or benefit may be created during production of a good, and/or during the consumption of that good. An example of a positive externality is that of education given to some individuals in a society leading to a greater prosperity for all in that society. A negative externality example is that of an individual consuming a cigarette in a crowded area where everybody else must passively smoke their cigarette and inherit the health risks.

Externalities are a form of market failure. Market failure describes a condition where the allocation of goods in a free market economy is not optimal. In practical terms, market failure is said to occur when individuals’ pursuit of self-interest leads to a negative result for society overall. This form of market failure can be addressed by internalising the externalised costs or benefits. In other words, any economic gains or losses received by third parties are captured and passed back to the parties involved in the originating transaction. There are a variety of economic mechanisms available to internalise externalities, such as command and control action or market-based methods like taxation, subsidies or assigning property rights.

Externalities in energy trade occur both in the production and the consumption ends of the transaction. These externalities, upon society, are typically negative - the details of why will be examined later. Initially, we will explore the underlying economic theory of negative externalities.

To fully understand the following theory discussion, some terms must first be defined. Marginal Private Cost (or MPC) is the willingness for a supplier to accept a price for goods produced as a function of quantity. Marginal Private Benefit (or MPB) is the willingness for a consumer to pay a price for goods to consume as a function of quantity. Pareto improvement is the act of reallocating the distribution of goods within an economy such that at least one individual is made better off without making any other individuals worse off. Deadweight loss denotes an inefficiency in goods allocation within an economy which could be made efficient using Pareto improvement.

Figure 2 illustrates the differences in marginal cost of goods production where externalities are accounted for. The MPC curve is the private cost of production to the supplier. The Marginal Social Cost (or MSC) adds the price of abatement of external social costs onto the MPC. In this instance, consuming goods does not carry any external social cost, and so MPB and Marginal Social Benefit (or MSB) are equivalent. The socially optimal trade occurs at quantity q^s and price p^s. Without accounting for externalities, the optimal trade occurs at q and p. The oversupply in quantity produced leads to a deadweight loss to society, however free market competition does not provide incentive for Pareto improvement towards social optimality. An example of a production externality in the energy context is a coal-fired electricity generator may sell electricity without abating emissions that impress a cost onto society.

Figure 3 illustrates an alternative situation where an external cost to society is present in the consumption of goods. In this instance, producing goods does not carry any external social cost, and so MPC is equivalent to MSC. Again the socially optimal trade occurs at quantity q^s and price p^s, and the optimal trade with accounting for externalities is at q and p. There is a deadweight loss to society in the oversupply of quantities traded when externalities in consumption of goods are not costed into the transaction. An example of a consumption externality in the energy context is the use of petrol in a car, providing transport to the consumer, without the consumer paying for engine emissions impressing a cost onto society.

The topic of negative externalities is particularly relevant to the energy market due to the nature of available energy production methods. Fossil fuels, to date, have been inexpensive to obtain, process and use. Some fossil fuels such as oil and gas are highly flexible due to their ease of transportability and high energy to mass ratio. It so happens that those which are used to produce the cheapest energy (coal and uranium) also carry the highest social costs^[2]. In general, with the present level of technology and infrastructure, methods boasting lower social costs also deliver higher private costs, and vice versa.

There are numerous reasons why externalities in the energy market have not been internalised in the past and the present. The cheap generation, sale and delivery of energy was seen as the clear path to rapid industrialisation during the 19th century^[6]. Only during these last decades has society begun to take heed of the growing external social and environmental costs being created by energy markets – degradation to health and the environment is now clear and present. Even so, today, the formation of global energy markets has forced energy suppliers to de-prioritise social and environmental considerations in order to stay competitive with a world of fierce market players. Also, while the true costs of these externalities are still being fiercely debated in global forums, the economic devices necessary to grow a socially-optimal energy market have not yet been instigated.

The failure to incorporate negative externalities into the price of energy has several categories of consequences. Each of these will be discussed in turn.

Neglecting to accommodate the social cost of energy has led to overdevelopment and overconsumption. An artificially low price creates an incorrect market signal that results in greater production than is warranted. The global marketplace has now developed an unhealthy, increasing demand for energy that cannot be easily recessed or even slowed.

The most topical consequence of energy use is the degradation of social and environmental public goods. A public good is a non-excludable, non-rival good, and thus is not owned by any particular party. The lack of property rights on the environment has enabled society at large to produce and consume energy with very limited knowledge or consideration of the external costs. The use of fossil fuels for energy is largely to blame for environmental damages, which can be divided into two categories; emissions related to climate change, and emissions not related to climate change.

Climate change is, by far, the most threatening and most wide-reaching result of failing to internalise the negative externalities of energy trade. The production and consumption of hydrocarbon based energy has made a major contribution to the quantity of carbon dioxide gas entering the atmosphere, which is the catalyst for many knock-on effects such as atmospheric warming, rising sea levels, and destabilised and intensified weather patterns. Further effects include glacial retreat, species extinctions, disease propagation and overall decreases in agricultural yields^[2]. While the heavily inertial nature of global climate change has made externalities difficult to quantify, the consequences of failing to abate these external by-products will result in profound costs for society the world over.

A multitude of other environmental and social costs are associated with the unabated externalities of energy trade. Emissions from fossil fuel energy suppliers affect the health and well-being of people in their vicinity, as well as the natural and built environment. Along with carbon dioxide, coal power stations emit sulphur dioxides, nitrous oxides, particulate matter and other toxic material which has a range of detrimental effects such as acid rain that decays structures and poisons crops, and invokes respiratory disease in people^[2]. Large cities of motor vehicle commuters create similar effects, along with haze, smog and noise. Oil spills and effluent leaks damage ocean sea life and in turn the yield from fishing. The transmission and consumption of electricity creates strong magnetic fields, which have been linked to cancer development and other health effects. Accidental explosions from power plants cost lives, with the fallout from nuclear incidents slowly killing thousands to date^[1]. Energy trade, without care, can be responsible for many non-trivial social and environmental costs.

Consuming finite resources without accounting for depletion creates inter-temporal consequences. To say an economic transaction is inter-temporally inefficient is to indicate that it is unsustainable in current form, and future transactions will have less value or no longer be possible. This is true to say of fossil fuel energy resources, as there is a fixed amount of coal, oil, gas and uranium worldwide. As stockpiles are exhausted, energy suppliers must spend more to access more technically or politically challenging sources. To this end, fossil fuel based energy tomorrow will ask a higher price than today. However, this scenario is not internalised in today’s transactions, and thus becomes a growing externality to tomorrow’s energy trader parties.

Failing to reflect the total social costs in free-market energy prices has resulted in alternative energy technologies to remain commercially underdeveloped. Alternative stationary electricity generation techniques such as solar or wind attempt to compete in the open market and are largely unsuccessful. The same can be said for transportable fuel systems such as hydrogen or electric engines. The cause of this failure is two-fold. Firstly, decades of improvement and infrastructure development have seen fossil fuel based energy systems inherit an underlying subsidy in today’s marketplace. De-centralised systems that cannot provide baseload energy are more challenging to integrate into conventional grids^[6]. Similarly for transportable fuels, petrol is available anywhere yet no hydrogen or electricity stations exist to refill alternative engines. Alterative energy systems have not had the same investment historically, leaving them with room for improvement and the contracts with the conventional fossil-based energy suppliers. The playing field may be evened for these alternative energy suppliers by a subsidy that recognises the social benefits in comparison to conventional stationary energy supply.

The second cause of failure for competitive alternative energy supply is in the failure to internalise the social and environmental costs of fossil-based energy suppliers into their energy price. If the costs of abatement and damage control (as discussed earlier) were entirely factored into the cost of fossil fuel energy, alternative fuel sources would not only be competitive, but in fact the preferred choice^[4].

Increased geopolitical risk is also an outcome of the failure to promote a competitive market for alternative energy systems. As fossil fuel resources continue to diminish, and consumer demands fail to reshape without incentive, the need to capture and secure more fossil resources will become a vast and costly political and military exercise. Energy security has been a vital concern since the oil crises in the 1970s^[2]. While Australia is a net energy exporter, the same cannot be said for most other developed nations, whose failure to negate their fossil fuel inter-temporal inefficiencies has resulted in growing import dependence.

This paper has covered the economic theory of externalities, detailed the externalities associated with energy production and discussed the consequences of failing to incorporate externalities into the cost of energy. The past and present show us that the trade of energy has many significant social and environmental externalities that must be abated or controlled to prevent greater consequences than those already on the horizon.

References

^[1] Damien, M., 1992. Nuclear Power: The ambiguous lessons of history. Energy Policy July.
^[2] Hohmeyer, O. 1992. Renewables and the Full Costs of Energy, Energy Policy April: 365-375.
^[3] McHugh, A. 2007. Energy Economics Course Notes: Externalities. Murdoch University.
^[4] Nicklas, M. 1993. Energy Politics: Can we achieve a sustainable energy path? Solar Energy Vol. 50, No. 4.
^[5] Owen, A. 2004. Environmental Externalities, Market Distortions and the Economics of Renewable Energy Technologies. The Energy Journal Vol. 25, No. 3.
^[6] Shlapfer, A. 2007. Energy Economics Course Notes: The Structure of Energy Supply Systems. Murdoch University.
^[7] Wikipedia contributors. 2008. Externality. http://en.wikipedia.org/wiki/Externality (accessed 18 March 2008).

Controlling the rendering of a custom field’s value in most display modes is straight-forward through overrides to the SPField method GetFieldValueAsHtml(object) and the Render(…) methods of BaseFieldControl.  When it came to rendering the value on the list display (i.e. AllItems.aspx) I found that SharePoint limited me to doing this through the RenderPattern element in the field type definition XML, with the caveat that any values, properties or calculations be limited to the CAML View Schema elements. The MSDN documentation on Patterns of Custom Field Rendering hints that a DisplayTemplate specification will let you gain control of the display mode, including the list display. After messing around for a while I felt quite confident that it didn’t include the list display mode.

Some Googling later, I found someone who had bent the rules a little to achieve complete control over display list value rendering. This IconSet custom calculated field project uses a custom RenderPattern to generate a script reference to a custom aspx page that dynamically renders some document.write(…) code that then renders HTML. Values necessary to identifying which item and field are supplied by the CAML and passed by URL parameters.

Cunning it is, although not exactly ideal. Every rendered value of your custom field must perform this additional page query to the server, thus lists with many values will take significantly longer to render. Unfortunately so far I’ve found no alternatives to gaining full control of display list rendering.

Note that this procedure is only required when you can’t render the correct output using the decision logic available in the CAML View Schema. In my case I chose not use the simple Text field type as the parent type instead of the popular MultiColumn field type.

My RenderPattern XML looks like this:

    <RenderPattern Name="DisplayPattern">
        <IfEqual>
            <Expr1>
                <Column />
            </Expr1>
            <Expr2 />
            <Then />
            <Else>
                <HTML>
                    <![CDATA[<script language="javascript" src="../../_layouts/zmeng/]]>
                    <![CDATA[DigitalSignature/DigitalSignatureDisplay.aspx?ListId=]]>
                    <List />
                    <![CDATA[&ItemId=]]>
                    <ID />
                    <![CDATA[&FieldDisplayName=]]>
                    <Property Select="DisplayName"/>
                    <![CDATA["></script>]]>
                </HTML>
                </Else>
        </IfEqual>
    </RenderPattern>

The <IfEqual> tests whether the column has a value, and if not it avoids making a purposeless server request. Supplying the list GUID, item ID and list column display name, the receiving aspx page can query the value then render as necessary.

The receiving class is as below. Remember to set AutoEventWireup="true" in the connecting aspx file so the Page_Load method will be called.

    public partial class DigitalSignatureDisplay : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string listId = Request.QueryString.Get("ListId").ToString();
            string itemId = Request.QueryString.Get("ItemId").ToString();
            string displayName = Request.QueryString.Get("FieldDisplayName").ToString();

            Guid listGuid = new Guid(listId);
            int itemIndex = Int32.Parse(itemId);

            SPList spList = SPContext.Current.Web.Lists[listGuid];
            SPListItem spListItem = spList.GetItemById(itemIndex);

            // Create some useful HTML output here
            // using the list item's value
            string output = "<b>le output</b>"; 

            Page.Response.Write("document.write('"
                + output.Replace("'", @"\'") + "');");

            Page.Response.Flush();
        }
    }

The resultant effect of all that shown below.

In my opinion, the coolest, and by far the most creepy, is a quadruped that is capable of traversing almost any terrain while carrying 150kg on its back. It’s called BigDog, but I think it’s more of a big mountain goat that buzzes like a wasp. The video is great - BigDog stumbing around foolishly on black ice, and swaggers to reclaim balance after a guy kicks it with all his weight. Are we permitted a little schadenfreude for robotic animals?