Loading Remote Data using Select2 and Webservice - web-services

Question

I am using Select2 4.0.3 in my web forms .net application. I am trying to Load Remote data using a webservice, but its not working as expected.
First Issue am facing is that the webservice method is not getting called and am getting a console error:
System.InvalidOperationException: Missing parameter: text.
at System.Web.Services.Protocols.ValueCollectionParameterReader.Read(NameValueCollection collection)
at System.Web.Services.Protocols.HtmlFormParameterReader.Read(HttpRequest request)
at System.Web.Services.Protocols.HttpServerProtocol.ReadParameters()
at System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()
So I tried removing the paremeter from the webservice call
<WebMethod()> _
Public Function GetDataFromService() As String
Doing this the method got fired, but still the items in the select2 did not get populated (screenshot atached).
Can someone help me to figure out where am I making a mistake.
Here are the details:
Select2 Code in the Webform:
$("#ddlEntity").select2({
ajax: {
url: "Service/InvoiceHTMLService.asmx/GetDataFromService",
type: 'POST',
delay: 250,
params: {
contentType: 'application/json; charset=utf-8'
},
dataType: 'json',
data: function (term, page) {
return {
text: term,
};
},
processResults: function (data, params) {
// parse the results into the format expected by Select2
// since we are using custom formatting functions we do not need to
// alter the remote JSON data, except to indicate that infinite
// scrolling can be used
params.page = params.page || 1;
return {
results: data.items,
pagination: {
more: (params.page * 30) < data.total_count
}
};
},
cache: true
},
escapeMarkup: function (markup) { return markup; }, // let our custom formatter work
minimumInputLength: 1,
templateResult: formatRepo, // omitted for brevity, see the source of this page
templateSelection: formatRepoSelection // omitted for brevity, see the source of this page
});
WebService Method:
<WebMethod()> _
Public Function GetDataFromService(text As String) As String
Return "{['id':1, 'text':'Test1'],['id':2, 'text':'Test2']}"
End Function

Answer 1

Try this please
var fd = new FormData();
fd.append("text",term);
ajax: {
url: "Service/InvoiceHTMLService.asmx/GetDataFromService",
type: 'POST',
delay: 250,
params: {
contentType: 'application/json; charset=utf-8'
},
dataType: 'json',
data: fd
...

Answer 2

I think you did not create template for this select2. since you are using templateResult and templateSelection it requires template or you can remove those two options.
For your reference : https://select2.github.io/examples.html#templating
Updated:
they have changed query callback from
data: function (term, page) {
return {
text: term,
};
},
into
data: function (params) {
return {
q: params.term, // search term
page: params.page
};
},