Jquery - Try to send data to Ajax but data is null

Question

There is function that get name from database using Jquery Ajax. This function have input parameter that I get it with below code:

var value = $(this).parent().find(":checkbox").val();
var typeSelect = GetLayerGeometries(value);

Then send value to ajax function:

Ajax Function:

function GetLayerGeometries(LayerName) {
    var data;
    $.ajax({
        url: 'GetLayerGeometries.aspx/GetLayerGeometry',
        data: '{"LayerName":"' + LayerName + '"}',
        async: false,
        success: function (resp) {
            data = resp;
            callback.call(data);
        },
        error: function () { }
    });
    return data;
}

C# Function:

protected void Page_Load(object sender, EventArgs e)
{
    string test = Request.Form["LayerName"];
    GetLayerGeometry(Request.Form["LayerName"]);
}

public void GetLayerGeometry(string LayerName)
{
    WebReference.MyWebService map = new WebReference.MyWebService();
    string Name = map.GetLayerGeometries(LayerName);

    if (Name != null)
        Response.Write(Name);            
}

My problem: LayerName is null.

I use this link and test all ways,but LayerName still is null.

You are passing the data as JSON but trying to read it as if it was form encoded - I think that's your problem. — abagshaw, Aug 05 '17 at 17:03
you need to read the data as JSON and not like it was some data send by a form — sheplu, Aug 05 '17 at 17:04

score 1 · Answer 1 · answered Aug 05 '17 at 17:08

function GetLayerGeometries(LayerName) {
    var data;
    $.ajax({
        url: 'GetLayerGeometries.aspx/GetLayerGeometry',
        data: {"LayerName":LayerName},
        async: false,
        success: function (resp) {
            data = resp.d;
            callback.call(data);
        },
        error: function () { }
    });
    return data;
}

[WebMethod]
public static string GetLayerGeometry(string LayerName)
{
    return LayerName
}

you need to use web Method just like above method.

LayerName still is null. – Farzaneh Talebi Aug 06 '17 at 05:00 — Farzaneh Talebi, Aug 06 '17 at 05:00

score 0 · Answer 2 · answered Aug 05 '17 at 17:09

0

The problem is, you are trying to parse the request body as if it was form encoded, which it is not. You've passed the data using JSON so you need to parse it appropriately.

Use the following in your C# to read the request variables from JSON using Json.NET:

protected void Page_Load(object sender, EventArgs e)
{
    string requestBody = StreamReader(Request.InputStream).ReadToEnd();
    dynamic parsedBody = JsonConvert.DeserializeObject(requestBody);
    string test = parsedBody.LayerName;
}

answered Aug 05 '17 at 17:09

abagshaw

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LayerName still is null. – Farzaneh Talebi Aug 06 '17 at 05:00
Do you mean `test` ends up being `null`? What does `requestBody` end up being? – abagshaw Aug 06 '17 at 05:06

score 0 · Accepted Answer · answered Aug 06 '17 at 08:59

You need to stringify value and then send it, it will work

function GetLayerGeometries(LayerName) {
    var data;
    $.ajax({
        url: 'GetLayerGeometries.aspx/GetLayerGeometry',
        data: { LayerName: JSON.stringify(LayerName) }, // make this change
        async: false,
        success: function (resp) {
            data = resp;
            callback.call(data);
        },
        error: function () { }
    });
    return data;
}

Jquery - Try to send data to Ajax but data is null

3 Answers3