65 lines
2.2 KiB
C#
65 lines
2.2 KiB
C#
using Avalonia.Data;
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using Avalonia.Data.Converters;
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using Avalonia.Markup.Xaml;
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using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Globalization;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Cowain.Base.Converters;
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/// <summary>
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/// 通用ID到对象属性值转换器
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/// 支持通过ID从集合中查找对象，并返回该对象的指定属性值
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/// </summary>
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public class MultiIdToPropertyConverter : MarkupExtension, IMultiValueConverter
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{
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public object? Convert(IList<object?> values, Type targetType, object? parameter, CultureInfo culture)
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{
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try
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{
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// 参数说明：values[0]=ID值, values[1]=集合对象, values[2]=目标属性名（可选）
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if (values.Count < 2 || values[0] is null || values[1] is null)
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return BindingOperations.DoNothing;
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object? id = values[0];
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object? collection = values[1];
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string targetProperty = (values.Count >= 3 && values[2] is string s && !string.IsNullOrEmpty(s))
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? s
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: "Name"; // 默认属性名为 "Name"
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// 从集合中查找项
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object? item = (id is not null && collection is not null) ? FindItemById(collection, id) : null;
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if (item is null) return "Null";
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var propertyInfo = item.GetType().GetProperty(targetProperty);
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return propertyInfo?.GetValue(item) ?? "Null";
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}
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catch
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{
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return BindingOperations.DoNothing;
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}
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}
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private object? FindItemById(object collection, object id)
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{
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switch (collection)
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{
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case IDictionary dict:
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return id is not null && dict.Contains(id) ? dict[id] : null;
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case IEnumerable enumerable:
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foreach (var item in enumerable)
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{
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var itemId = item?.GetType().GetProperty("Id")?.GetValue(item);
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if (itemId is not null && itemId.Equals(id))
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return item;
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}
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break;
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}
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return null;
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}
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public override object ProvideValue(IServiceProvider serviceProvider) => this;
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} |
