Question

I am making a call to a webservice from jquery and trying to return an List (I have also tried a string[]). When I get the results back I can see it holds an array with the values I need, but I can not iterate through them in Javascript because there is no length value.

my C# Webservice is as follows:

    [WebMethod]
    public string[] GetMultiChoiceOptions(int keyId)
    {
        string connectionString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["OBConnectionString"].ConnectionString;
        SitesUtil db = new SitesUtil(connectionString);
        List<MultiChoiceOption> keys = db.GetMultiChoiceOptions(keyId, 1); //TO DO CHANGE THIS TO REAL USERID

        return keys.Select(a => a.OptionValue).ToArray();
    }

and My Jquery/javscript call is as follows:

function GetKeys(keyid) {

    var pageUrl = '<%=ResolveUrl("~/WebService/UpdateDatabase.asmx")%>'
    $.ajax({
        type: "POST",
        url: pageUrl + "/GetMultiChoiceOptions",
        data: '{keyId:' + keyid + '}',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: GetKeysSuccessCall,
        error: OnErrorCall
    });
}

function GetKeysSuccessCall(response) {
    /* TO DO */
    var i = 0;
    for (i =0; i < response.length; i++) {
        $("#popupList").append('<li>' + response[i] + '</li>');                
        }       
}

I’m not sure how I deal with an array without a length in javascript?

Answer 1

First, use Google Console. Best and helpful.

To see what you receive, use console.log(response); (instead of alert and do NOT use in IE because it doesn’t know console)

try first of all

$.ajax({
        type: "POST",
        url: pageUrl + "/GetMultiChoiceOptions",
        data: '{keyId:' + keyid + '}',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function(response){
          GetKeysSuccessCall(response);
        },
        error: function(msg) {
           OnErrorCall(msg);
         }
    });

And one more :

function GetKeysSuccessCall(response) {
    /* TO DO */
    var i = 0;
    for (i =0; i < response.length; i++) {
        $("#popupList").append('<li>' + response[i] + '</li>');                
        }       
}

repsonse must be instead of item