How send complex data type with ajax to the action in controller in ASP.NET MVC

You can use HTTP post as the following code to do it, you just creat a class with Key and Value, and use it in Controller with a String variable, on a HTTP post Function.

I am not expert in C# I did translate online from my VB code that work well.

In your Views (.cshtml) :

<input id="Button1" type="button" value="button" onclick="SaveMe()" />
<script>
    function SaveMe() {
        var GUID = '6a580cf1-2f05-4621-8a67-8fe0bdd559c2';

        // Creat Object
        var lineItems = new Object();
        lineItems.Entrys = new Array();

        // Example Filling your object, but of course you can get data from another place ...
        lineItems.Entrys[0] = new Object({ Key: '052c5941-233a-4bd2-80e1-7cfffa34ca44', Value: 'Salary1' });
        lineItems.Entrys[1] = new Object({ Key: '00000000-0000-0000-0000-000000000004', Value: 'Salary2' });
        lineItems.Entrys[2] = new Object({ Key: '00000000-0000-0000-0000-000000000005', Value: 'Salary3' });


        $.ajax({
            type: "POST",
            url: "/Home/AjaxMethodDigestFile",
            data: JSON.stringify({ Entrys: lineItems.Entrys, GUID: GUID }),
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (response) { alert(response.message); },
            failure: function (response) { alert("failure"); },
            error: function (response) { alert("error"); }
        });
    }
</script>

In your Models:

namespace MyModel1.ViewModel
{
    public class MyClass1
    {
        public string Key { get; set; }
        public string Value { get; set; }
    }
}

In your Controllers:

[HttpPost]
public JsonResult  AjaxMethodDigestFile(ICollection<MyModel1.ViewModel.MyClass1> Entrys, string GUID)
{
    string message = "";
    int counter = 0;

    foreach (var entry in Entrys)
    {
        // How to use this data example
        string Key = entry.Key;
        string Value = entry.Value;
        counter += 1;
        message += Value + ": " + Key + Constants.vbCrLf;
    }

    // The following lines are not necessary, it's just an example code to know what happen and return it to client side ...
    if (counter > 0)
        message = counter.ToString() + " Entrys received" + Constants.vbCrLf + message;
    else
        message = "no entrys";


    var response = new { counter, message };
    
    return Json(response);
}