Kendo UI Dropdownlist slow loading from a large datasource - kendo-ui

Question

I'm using Kendo dropdownlist in a template. It loads a list of client names which are used to sign a record. The client name list has 8k entries.
The form loads ok but if I select the dropdownlist to change the client name it takes around 10 seconds for the list to appear. Is there something I can do to speed this up?
My datasource:
var dsClients = new kendo.data.DataSource({
transport: {
read: {
url: "/data/clients/key",
dataType: "jsonp"
},
parameterMap: function(options, operation) {
if (operation === "read") {
return options;
}
}
},
serverSorting: true,
sort: [{ field: "text", dir: "asc" }]
});
The element in my template:
<input name="idclt_clm" data-bind="value:idclt_clm" data-value-field="value"
data-text-field="text" data-option-label="Select" data-source="dsClients"
data-role="dropdownlist" required validationMessage="Required" />

Answer 1

There are 2 options that I know of.
You can add virtualization, which I just found from
Kendo.
You can turn of auto-bind and use a search filter that require 2 characters before it triggers a search. Below is how I've done it with asp.net and JS
#(Html.Kendo()
.DropDownList()
.Name("GridName")
.HtmlAttributes(new { #class = "form-control" })
.DataSource(ds => ds.Read(read =>
read.Action("YourFunction","YourController").Data("filterFunction"))
.ServerFiltering(true))
.MinLength(2)//number of characters for a valid search
.Delay(250)//milliseconds delay to trigger search
.AutoClose(false)
.AutoBind(false)
.IgnoreCase(true)
.DataTextField("Text")
.DataValueField("Value")
.Placeholder("Enter at least 2 letters to search")
.Filter(FilterType.Contains)
)
<script>
function filterFunction() {
return {
text: $("#GridName").data("kendoDropDownList").input.val()
};
}
</script>
If the search is still slow, you can change the number of characters

Answer 2

Well, what if you do both? Is maybe not the best aproach, but for me it worked.
I have a ComboBox that gets its info from an cascade event, so it would try either way to fill it up. So, after send the request to fill on server-side, I have a client-side event:
.Filter(Contains).MinLength(n).Filtering("Action")
Which will get to server throgh ajax to catch a Session var with the table/list with which you are trying to fill up your CB. Then filtering the desired list and send it back to your CB.