将图像绑定到xamarin形式的列表视图中

Question

我想在点击它时将图像源从white.png更改为blue.png。我试过了，但似乎没有用。

列出ItemsSource模型

public ImageSource ColorImage { get; set; }

查看模型

public ICommand SwitchIMGCommand
            {
                get;
                set;
            }



private void AddImg(object obj)
  {
     var selection = obj as ExistingModel;
     selection.ColorImage = "FilledIcon.png";**
     ColorImage= "FilledIcon.png";**I tried this and it doesnt change 
     to this img
  }



private ImageSource imagePath = "white.png";
        public ImageSource ColorImage
        {
            get { return imagePath; }
            set
            {
                imagePath = value;
                PropertyChanged(this, new PropertyChangedEventArgs("ColorImage"));
            }
        }

构造函数

SwitchIMGCommand = new Command(AddImg);

XAML

<Image
    Source="{Binding ColorImage}">  
    <Image.GestureRecognizers>
    <TapGestureRecognizer
    Command="{Binding Source={x:Reference listView}, Path=BindingContext.SwitchIMGCommand}" CommandParameter="{Binding .} "
     NumberOfTapsRequired="1" />
     </Image.GestureRecognizers>
  </Image>

Answer 1

似乎图像在列表视图的ViewCell中。

您应该在模型中定义ColorImage。

public class MyModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;


    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    private string imagePath;
    public string ColorImage
    {
        get { return imagePath; }
        set
        {
            imagePath = value;
            NotifyPropertyChanged("ColorImage");
        }
    }


    //...other properties     

    public MyModel()
    {
       ColorImage = "white.png";
    }
}

在您的视图模型中

private void AddImg(object obj)
{
   var model = obj as MyModel;

   model.ColorImage = "imgcolorblue.png";

}

Answer 2

您为参数“ ColorImage”使用了错误的类型。图像的来源是ImageSource类型。

假设您在项目上正确设置了图像，以下代码应该可以解决您的问题

private void AddImg(object obj)
{
    ColorImage = ImageSource.FromFile("imgcolorblue.png");
}

也通过ImageSource更改“ ColorImage”的类型。