MVC如何将数组（Guid CustomerID）和单个值传递给控制器

Question

I am using JavaScript and ajax to pass an array and a single value to the controller, When controller method being call the single value is passed in but not the (array of customerID) and I wonder why, here is the code!

Here is my JavaScript and ajax call:

var arrayOfCustomerID = ['11111111 - 1111 - 1111 - 1111 - 111111111112', '4b732df8-3bbc-4eab-9bf1-da98cc46d527' ,
'3e74adeb-31a8-4d6f-a66b-a34500c3acc0',' 14897bf4-f5d0-4548-a74d-a34f00ae9cad'];

var version = '3.0';

$.ajax({
         url: '/Updates/UpdateCustomers',
         type: "POST",
         datatype: "json",
         traditional: true,
         data: {
           CustomerIDs: JSON.stringify(arrayOfCustomerID),
           Version: version
               },
         success: function (data) {
         alert("success");
         }
       });

---

Here is my class:

public class SelectedCustomersWithVersion 
    {
        public List<Guid> CustomerIDs { get; set; }

        public string version { get; set;  }
    }

---

Finally here is my controller method:

[HttpPost]
public ActionResult UpdateCustomers(SelectedCustomersWithVersion model)
{
 IList a = model.CustomerIDs.ToList();
 var b = model.version;
 return view();
}

when I put a break point on my controller model I got model.CustomerIds: Count = 0, model.Version: "3.0"

I don't know why I am getting Customerids= 0 count, is there something wrong with the code? Thanks for help !

Answer 1

This is due to the way you are passing the parameters to the action method. In your current approach you are sending them as one parameter which is received as a comma separated string which the binder doesn't convert into a List<Guid> .

The following Fiddler capture shows how you are sending your parameters:

In order for the model binder to correctly bind a List<T> the parameters need to be sent separately either with the same name or with an index assigned.

For example, the following 2 approaches will both work:

?customerIDs=1111...&customerIDs=4b73...&customerIDs=3e...

?customerIDs[0]=1111...&customerIDs[1]=4b73...&customerIDs[2]=3e...

In the second example note that the indexes have to be zero based and without gaps.

In order to get this to work you can change your jQuery code to:

arrayOfCustomerID = [];
arrayOfCustomerID[0] = '11111111 - 1111 - 1111 - 1111 - 111111111112';
arrayOfCustomerID[1] = '4b732df8-3bbc-4eab-9bf1-da98cc46d527';
arrayOfCustomerID[2] = '3e74adeb-31a8-4d6f-a66b-a34500c3acc0';
arrayOfCustomerID[3] = ' 14897bf4-f5d0-4548-a74d-a34f00ae9cad';

var version = '3.0';

$.ajax({
    url: '/api/values',
    type: "POST",
    datatype: "json",
    traditional: true,
    data: {
        CustomerIDs: arrayOfCustomerID,
        Version: version
    },
    success: function (data) {
        alert("success");
    }
});

This will send the parameters like this:

Which will then successfully get bound to your model:

One final note, I had to remove the spaces from your first Guid in order to get it to bind.

Answer 2

I think MVC is not able to automatically bind an array of strings (client side) to an array of GUIDs (server side).

Try changing your view model ( SelectedCustomersWithVersion ) to use strings instead.