Hi,

As you know already, SharePoint 2010 uses an XSLT engine to render views & custom field types. You can still use CAML views but it defaults to XLST.

I've just built a custom field type whose the parent type was "Choice". While building the corresponding XSLT, I didn't find the "mode" I was supposed to use...So, in case, the same story happens to you, an easy way to know which mode you're supposed to use is to examine the out-of-the-box file delivered with any SharePoint installation.

I'm talking about this file:

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS\XSL\fldtypes.xsl

When opening that file, you can look at the template called PrintField and this is what you'll find:

<xsl:choose>
      <xsl:when test="$Type='DateTime'">
        <xsl:apply-templates select="." mode="DateTime_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='Computed'">
        <xsl:choose>
          <xsl:when test="$Name='LinkTitle' or $Name='LinkTitleNoMenu'">
            <xsl:apply-templates select="." mode="Computed_LinkTitle_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='LinkFilename' or $Name='LinkFilenameNoMenu'">
            <xsl:apply-templates select="." mode="Computed_LinkFilename_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='DocIcon'">
            <xsl:apply-templates select="." mode="Computed_DocIcon_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
              <xsl:with-param name="folderUrlAdditionalQueryString" select="$folderUrlAdditionalQueryString"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='NameOrTitle'">
            <xsl:apply-templates select="." mode="Computed_NameOrTitle_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='URLwMenu'">
            <xsl:apply-templates select="." mode="Computed_URLwMenu_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='HealthReportSeverityIcon'">
            <xsl:apply-templates select="." mode="Computed_HealthReportSeverityIcon_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='LinkDiscussionTitle' or $Name='LinkDiscussionTitleNoMenu'">
            <xsl:apply-templates select="." mode="Computed_LinkDiscussionTitle_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:when>
          <xsl:when test="$Name='Threading' or $Name='BodyAndMore'">
            <xsl:apply-templates select="." mode="Computed_body">
              <xsl:with-param name="thisNode" select="$thisNode" />
              <xsl:with-param name="Position" select="$Position" />
            </xsl:apply-templates>
          </xsl:when>
          <xsl:otherwise>
            <xsl:apply-templates select="." mode="Computed_body">
              <xsl:with-param name="thisNode" select="$thisNode"/>
            </xsl:apply-templates>
          </xsl:otherwise>
        </xsl:choose>
      </xsl:when>
      <xsl:when test="$Type='Attachments'">
        <xsl:apply-templates select="." mode="Attachments_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='User' or $Type='UserMulti'">
        <xsl:apply-templates select="." mode="User_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='Note'">
        <xsl:apply-templates select="." mode="Note_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='Text'">
        <xsl:apply-templates select="." mode="Text_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='Number' or $Type='Currency'">
        <xsl:apply-templates select="." mode="Number_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='Lookup' or $Type='LookupMulti' or $Type='WorkflowStatus'">
        <xsl:apply-templates select="." mode="Lookup_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='URL'">
        <xsl:apply-templates select="." mode="URL_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='CrossProjectLink'">
        <xsl:apply-templates select="." mode="CrossProjectLink_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='Recurrence'">
        <xsl:apply-templates select="." mode="Recurrence_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="$Type='AllDayEvent'">
        <xsl:apply-templates select="." mode="AllDayEvent_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:when test="@CAMLRendering='TRUE'">
        <xsl:apply-templates select="." mode="CAMLRendering_body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:when>
      <xsl:otherwise>
        <xsl:apply-templates select="." mode="body">
          <xsl:with-param name="thisNode" select="$thisNode"/>
        </xsl:apply-templates>
      </xsl:otherwise>
    </xsl:choose>

from which you can conclude that:

DateTime == DateTime_body
Computed == Computed_LinkTitle_body || Computed_LinkFilename_body || Computed_DocIcon_body || Computed_NameOrTitle_body || Computed_URLwMenu_body || Computed_HealthReportSeverityIcon_body || Computed_LinkDiscussionTitle_body || Computed_body
Attachments == Attachments_body
User || UserMulti == User_body
Note == Note_body
Text == Text_body
Number || Currency == Number_body
Lookup || LookupMulti || WorkflowStatus == Lookup_body
URL==URL_body
CrossProjectLink == CrossProjectLink_body
Recurrence == Recurrence_body
AllDayEvent == AllDayEvent_body

and for all the other types, the mode is body :).

All, you're sure? Actually yes but there is a trap, if you work with MultiColumn field types, then, you'll have to use the Note_body mode because MultiColumn actually inherits from Note in its field definition that you can find in:

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\XML\fldtypes.xml

<FieldType>
        <Field Name="TypeName">MultiColumn</Field>
        <Field Name="ParentType">Note</Field>
        <Field Name="UserCreatable">FALSE</Field>
        <Field Name="Sortable">FALSE</Field>
        <Field Name="Filterable">FALSE</Field>
        <RenderPattern Name="DisplayPattern">
            <Switch>
                <Expr><Column/></Expr>
                <Case Value="">
                </Case>
                <Default>
                    <Column SubColumnNumber="0" HTMLEncode="TRUE"/>
                </Default>
            </Switch>
        </RenderPattern>
</FieldType>

Happy coding