英文:
Setter not working in model
问题
我正在尝试理解MVC架构并学习Go语言,我正在编写这段代码。我遇到了一个问题,即无法从控制器中更改模型中的值。
目前的代码创建了一个只包含一个字符串的模型,视图在终端上显示该字符串,但控制器无法更改它(它可以正常获取用户输入)。
目前在终端上显示的文本如下:
Hello World!
asdf //我的输入
Hello World!
而我希望得到的输出应该是这样的:
Hello World!
asdf //我的输入
asdf
以下是我的文件:
model.go:
package models
type IndexModel struct {
Text string
}
func (m *IndexModel) InitModel() string {
return m.Text
}
func (m *IndexModel) SetText(newText string) {
m.Text = newText
}
view.go:
package views
import "github.com/jufracaqui/mvc_template/app/models"
type IndexView struct {
Model models.IndexModel
}
func (v IndexView) Output() string {
return v.Model.Text
}
controller.go:
package controllers
import "github.com/jufracaqui/mvc_template/app/models"
type IndexController struct {
Model models.IndexModel
}
func (c IndexController) ChangeText(userInput string) {
c.Model.SetText(userInput)
}
main.go:
package main
import (
"bufio"
"os"
"fmt"
"github.com/jufracaqui/mvc_template/app/controllers"
"github.com/jufracaqui/mvc_template/app/models"
"github.com/jufracaqui/mvc_template/app/views"
)
func main() {
handleIndex()
}
func handleIndex() {
model := models.IndexModel{
"Hello World!",
}
controller := controllers.IndexController{
model,
}
viewIndex := views.IndexView{
model,
}
fmt.Println(viewIndex.Model.Text)
reader := bufio.NewReader(os.Stdin)
text, _ := reader.ReadString('\n')
controller.ChangeText(text)
fmt.Println(viewIndex.Model.Text)
}
编辑:
根据@JimB的回答,我的代码如下所示:
model.go:
package models
type IndexModel struct {
Text string
}
func (m *IndexModel) InitModel() string {
return m.Text
}
view.go:
package views
import "github.com/jufracaqui/mvc_template/app/models"
type IndexView struct {
Model *models.IndexModel
}
func (v IndexView) Output() string {
return v.Model.Text
}
controller.go:
package controllers
import "github.com/jufracaqui/mvc_template/app/models"
type IndexController struct {
Model *models.IndexModel
}
func (c IndexController) ChangeText(userInput string) {
c.Model.Text = userInput
}
main.go:
package main
import (
"bufio"
"os"
"fmt"
"github.com/jufracaqui/mvc_template/app/controllers"
"github.com/jufracaqui/mvc_template/app/models"
"github.com/jufracaqui/mvc_template/app/views"
)
func main() {
handleIndex()
}
func handleIndex() {
model := models.IndexModel{
"Hello World!",
}
m := &model
controller := controllers.IndexController{
m,
}
viewIndex := views.IndexView{
m,
}
fmt.Println(viewIndex.Model.Text)
reader := bufio.NewReader(os.Stdin)
text, _ := reader.ReadString('\n')
controller.ChangeText(text)
fmt.Println(viewIndex.Model.Text)
}
英文:
I am making this code trying to understand the MVC architecture while learning Go, and I am stuck trying to change values in the model from the controller.
The code right now creates a model that only holds a string, the view shows that string on the terminal, but the controller can not change it (it gets the user input without any problem).
Right now the text I get in the terminal is like this:
Hello World!
asdf //my input
Hello World!
And the output I would like to get would be like this:
Hello World!
asdf //my input
asdf
Here are my files:
model.go
package models
type IndexModel struct {
Text string
}
func (m *IndexModel) InitModel() string {
return m.Text
}
func (m *IndexModel) SetText(newText string) {
m.Text = newText
}
view.go
package views
import "github.com/jufracaqui/mvc_template/app/models"
type IndexView struct {
Model models.IndexModel
}
func (v IndexView) Output() string {
return v.Model.Text
}
controller.go
package controllers
import "github.com/jufracaqui/mvc_template/app/models"
type IndexController struct {
Model models.IndexModel
}
func (c IndexController) ChangeText(userInput string) {
c.Model.SetText(userInput)
}
main.go:
package main
import (
"bufio"
"os"
"fmt"
"github.com/jufracaqui/mvc_template/app/controllers"
"github.com/jufracaqui/mvc_template/app/models"
"github.com/jufracaqui/mvc_template/app/views"
)
func main() {
handleIndex()
}
func handleIndex() {
model := models.IndexModel{
"Hello World!",
}
controller := controllers.IndexController{
model,
}
viewIndex := views.IndexView{
model,
}
fmt.Println(viewIndex.Model.Text)
reader := bufio.NewReader(os.Stdin)
text, _ := reader.ReadString('\n')
controller.ChangeText(text)
fmt.Println(viewIndex.Model.Text)
}
Edit:
How my code ended up after @JimB answer:
model.go:
package models
type IndexModel struct {
Text string
}
func (m *IndexModel) InitModel() string {
return m.Text
}
view.go:
package views
import "github.com/jufracaqui/mvc_template/app/models"
type IndexView struct {
Model *models.IndexModel
}
func (v IndexView) Output() string {
return v.Model.Text
}
controller.go:
package controllers
import "github.com/jufracaqui/mvc_template/app/models"
type IndexController struct {
Model *models.IndexModel
}
func (c IndexController) ChangeText(userInput string) {
c.Model.Text = userImput
}
main.go:
package main
import (
"bufio"
"os"
"fmt"
"github.com/jufracaqui/mvc_template/app/controllers"
"github.com/jufracaqui/mvc_template/app/models"
"github.com/jufracaqui/mvc_template/app/views"
)
func main() {
handleIndex()
}
func handleIndex() {
model := models.IndexModel{
"Hello World!",
}
m := &model
controller := controllers.IndexController{
m,
}
viewIndex := views.IndexView{
m,
}
fmt.Println(viewIndex.Model.Text)
reader := bufio.NewReader(os.Stdin)
text, _ := reader.ReadString('\n')
controller.ChangeText(text)
fmt.Println(viewIndex.Model.Text)
}
答案1
得分: 7
IndexController.ChangeText
需要一个指针接收器,或者 IndexController.Model
需要是一个指针。你正在对 SetText
的副本调用 SetText
。
如果你希望对象是可变的,最好始终使用指针来引用结构体,并且只在确实需要时才使用显式结构体值。
英文:
IndexController.ChangeText
needs a pointer receiver, or IndexController.Model
needs to be a pointer. You're calling SetText
on a copy of the SetText
value.
If you expect things to be mutable, it's much easier to consistently use pointers to structs throughout, and make explicit struct values the exception when you really need them.
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库,让每个人都能够通过互相帮助和分享经验来进步。
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