Golang-如何获取复选框的所有值？ r.FormValue无法正常工作吗？

This is my HTML :

<input type="checkbox" name="product_image_id" value="0" />
<input type="checkbox" name="product_image_id" value="1" />
<input type="checkbox" name="product_image_id" value="2" />

If I check all the options and I use r.FormValue("product_image_id") to get the value of checked options, I will only get the value 0.

I mean I can only get the first value, and I can't get other value although it was checked.

Please help me. Thanks.

Request.FormValue only returns the first value if there is more than one. From the Documentation:

FormValue returns the first value for the named component of the query.

...

To access multiple values of the same key, call ParseForm and then inspect Request.Form directly.

r.FormValue returns the first value from the list of options instead use r.Form , this returns a list. you can access your values by r.Form["product_image_id"]

HTML

    <form method="post" name="myform" action="http://localhost:8081/post" >
     <input type="checkbox" name="product_image_id" value="Apple" />
     <input type="checkbox" name="product_image_id" value="Orange" />
     <input type="checkbox" name="product_image_id" value="Grape" />
     <input type="submit">
    </form>

Go

// ProcessCheckboxes will process checkboxes
func ProcessCheckboxes(w http.ResponseWriter, r *http.Request) {
    r.ParseForm()
    fmt.Printf("%+v
", r.Form)
    productsSelected := r.Form["product_image_id"]
    log.Println(contains(productsSelected, "Grape"))
}

func contains(slice []string, item string) bool {
    set := make(map[string]struct{}, len(slice))
    for _, s := range slice {
        set[s] = struct{}{}
    }
    _, ok := set[item]
    return ok
}

Output

Orange and Grape checboxes are checked and submitted

map[product_image_id:[Orange Grape]]
2016/10/27 16:16:06 true

Apple and Orange checboxes are checked and submitted

map[product_image_id:[Apple Orange]]
2016/10/27 16:17:21 false

HTML

<input type="checkbox" name="product_image_id" value="0" />
<input type="checkbox" name="product_image_id" value="1" checked/>
<input type="checkbox" name="product_image_id" value="2" checked/>
<input type="checkbox" name="product_image_id" value="3" />
<input type="checkbox" name="product_image_id" value="4" checked/>

GO

r.Form["product_image_id"][0] == "1"
r.Form["product_image_id"][1] == "2"
r.Form["product_image_id"][2] == "4"

It will be working.
Am I late?