Users were complaining about a slow lookupfield (shown as dropdowns) that contained over 2000 items. It was not only loading slow, they had issues with typing in values as well.
I asked this question at the msdn forum and had some great responses.
Jeroen Van Bastelaere told me that SP2010 dropdowns had a special behavior: if there are less then 20 items, SP renders the lookup field as a normal dropdownlist. If you have more then 20 items, it is rendered totally different: a textfield with ajax populating dropdown.
Forum user M_K_A then pointed me to a blogpost on codeproject. There, the writer noticed the same behavior.
He came up with a solution for customized edit/new pages: Setting the Indesign property to true on the formfield.
<SharePoint:FormField runat="server" InDesign="true"
ID="field_FieldName" ControlMode="New" FieldName="FieldName" />
The writer also links to another blog, sharepointegg by Wilson Jeung who has a jquery solution.
That solution hides the current control (be it a dropdown or a textfield) and replaces it with a new dropdownlist.
A copy of the code (don’t forget to reference to the jquery library:
<script>
$(document).ready(function () {
// Name of the column (Display Name)
var columnName = "Lookup";
// Override the Drop Down List
OverrideDropDownList(columnName);
// Main Function
function OverrideDropDownList(columnName) {
// Construct a drop down list object
var lookupDDL = new DropDownList(columnName);
// Do this only in complex mode...
if (lookupDDL.Type == "C") {
// Hide the text box and drop down arrow
lookupDDL.Obj.css('display', 'none');
lookupDDL.Obj.next("img").css('display', 'none');
// Construct the simple drop down field with change trigger
var tempDDLName = "tempDDLName_" + columnName;
if (lookupDDL.Obj.parent().find("select[ID='" + tempDDLName + "']").length == 0) {
lookupDDL.Obj.parent().append("<select name='" + tempDDLName + "' id='" + tempDDLName + "' title='" + tempDDLName +
"'></select>");
lookupDDL.Obj.parent().find("select[ID='" + tempDDLName + "']").bind("change", function () {
updateOriginalField(columnName, tempDDLName);
});
}
// Get all the options
var splittedChoices = lookupDDL.Obj.attr('choices').split("|");
// get selected value
var hiddenVal = $('input[name=' + lookupDDL.Obj.attr("optHid") + ']').val()
if (hiddenVal == "0") {
hiddenVal = lookupDDL.Obj.attr("value")
}
// Replacing the drop down object with the simple drop down list
lookupDDL = new DropDownList(tempDDLName);
// Populate the drop down list
for (var i = 0; i < splittedChoices.length; i++) {
var optionVal = splittedChoices[i];
i++;
var optionId = splittedChoices[i];
var selected = (optionId == hiddenVal) ? " selected='selected'" : "";
lookupDDL.Obj.append("<option" + selected + " value='" + optionId + "'>" + optionVal + "</option>");
}
}
}
// method to update the original and hidden field.
function updateOriginalField(child, temp) {
var childSelect = new DropDownList(child);
var tempSelect = new DropDownList(temp);
// Set the text box
childSelect.Obj.attr("value", tempSelect.Obj.find("option:selected").val());
// Get Hidden ID
var hiddenId = childSelect.Obj.attr("optHid");
// Update the hidden variable
$('input[name=' + hiddenId + ']').val(tempSelect.Obj.find("option:selected").val());
}
// just to construct a drop down box object. Idea token from SPServces
function DropDownList(colName) {
// Simple - when they are less than 20 items
if ((this.Obj = $("select[Title='" + colName + "']")).html() != null) {
this.Type = "S";
// Compound - when they are more than 20 items
} else if ((this.Obj = $("input[Title='" + colName + "']")).html() != null) {
this.Type = "C";
// Multi-select: multi-select column control on English and most other languages sites where Title looks like 'Column Name possible values'
} else if ((this.Obj = $("select[ID$='SelectCandidate'][Title^='" + colName + " ']")).html() != null) {
this.Type = "M";
// Multi-select: multi-select column control on a Russian site (and perhaps others) where Title like 'Выбранных значений: Column Name'
} else if ((this.Obj = $("select[ID$='SelectCandidate'][Title$=': " + colName + "']")).html() != null) {
this.Type = "M";
} else
this.Type = null;
} // End of function dropdownCtl
});
</script>
Visit the SharePointEgg blog for a SPservices cascadeddropdown solution!
