在选择器中添加项目的键值 [英] Adding key values for items in picker

问题描述

我正在使用XAMARIN选择器选择一个国家.这些国家/地区在选择器中进行了硬编码.有没有一种方法可以通过键值识别每个国家/地区名称.我使用SAPUI5以类似的方式完成了此操作.

I am using a XAMARIN picker to select a country. The countries are hard coded in the picker. Is there a way I could identify each country name through a key value. I have done this in a similar way using SAPUI5.

<core:Item key="AF" text="Afghanistan  " />
<core:Item key="AL" text="Albania  " />
<core:Item key="DZ" text="Algeria  " />
<core:Item key="VI" text="Amer.Virgin Is. " />

在某种意义上，我有没有办法在XAMARIN表单选择器中为每个国家/地区添加键值?

Similarily, is there a way for me to add a key value for each country in XAMARIN form picker?

推荐答案

否，xamarin选择器中的键属性可用.但是，您可以使用xamarin选择器类的Dictionary类和SelectedIndex属性来实现它.

No, Key property is available in xamarin picker. But, you can implement it using Dictionary class and SelectedIndex property of xamarin picker class.

通过使用以下代码片段进行实施:

class PickerDemoPage : ContentPage
        {
            // Dictionary to get Color from color name.
            Dictionary<string, Color> nameToColor = new Dictionary<string, Color>
            {
                { "Aqua", Color.Aqua }, { "Black", Color.Black },
                { "Blue", Color.Blue }, { "Fuschia", Color.Fuschia },
                { "Gray", Color.Gray }, { "Green", Color.Green },
                { "Lime", Color.Lime }, { "Maroon", Color.Maroon },
                { "Navy", Color.Navy }, { "Olive", Color.Olive },
                { "Purple", Color.Purple }, { "Red", Color.Red },
                { "Silver", Color.Silver }, { "Teal", Color.Teal },
                { "White", Color.White }, { "Yellow", Color.Yellow }
            };

            public PickerDemoPage()
            {
                Label header = new Label
                {
                    Text = "Picker",
                    FontSize = Device.GetNamedSize (NamedSize.Large, typeof(Label)),
                    HorizontalOptions = LayoutOptions.Center
                };

                Picker picker = new Picker
                {
                    Title = "Color",
                    VerticalOptions = LayoutOptions.CenterAndExpand
                };

                foreach (string colorName in nameToColor.Keys)
                {
                    picker.Items.Add(colorName);
                }

                // Create BoxView for displaying picked Color
                BoxView boxView = new BoxView
                {
                    WidthRequest = 150,
                    HeightRequest = 150,
                    HorizontalOptions = LayoutOptions.Center,
                    VerticalOptions = LayoutOptions.CenterAndExpand
                };

                picker.SelectedIndexChanged += (sender, args) =>
                    {
                        if (picker.SelectedIndex == -1)
                        {
                            boxView.Color = Color.Default;
                        }
                        else
                        {
                            string colorName = picker.Items[picker.SelectedIndex];
                            boxView.Color = nameToColor[colorName];
                        }
                    };

                // Accomodate iPhone status bar.
                this.Padding = new Thickness(10, Device.OnPlatform(20, 0, 0), 10, 5);

                // Build the page.
                this.Content = new StackLayout
                {
                    Children =
                    {
                        header,
                        picker,
                        boxView
                    }
                };

            }
        }

来源: https://developer.xamarin.com/api/type/Xamarin.Forms.Picker/

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