зеркало из https://github.com/DeGsoft/maui-linux.git
41 строка
1.3 KiB
C#
41 строка
1.3 KiB
C#
using System;
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using System.Collections.Generic;
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namespace Xamarin.Forms
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{
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public abstract class DataTemplateSelector : DataTemplate
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{
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Dictionary<Type, DataTemplate> _dataTemplates = new Dictionary<Type, DataTemplate>();
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public DataTemplate SelectTemplate(object item, BindableObject container)
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{
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var listView = container as ListView;
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var recycle = listView == null ? false :
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(listView.CachingStrategy & ListViewCachingStrategy.RecycleElementAndDataTemplate) ==
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ListViewCachingStrategy.RecycleElementAndDataTemplate;
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DataTemplate dataTemplate = null;
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if (recycle && _dataTemplates.TryGetValue(item.GetType(), out dataTemplate))
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return dataTemplate;
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dataTemplate = OnSelectTemplate(item, container);
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if (dataTemplate is DataTemplateSelector)
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throw new NotSupportedException(
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"DataTemplateSelector.OnSelectTemplate must not return another DataTemplateSelector");
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if (recycle)
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{
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if (!dataTemplate.CanRecycle)
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throw new NotSupportedException(
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"RecycleElementAndDataTemplate requires DataTemplate activated with ctor taking a type.");
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_dataTemplates[item.GetType()] = dataTemplate;
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}
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return dataTemplate;
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}
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protected abstract DataTemplate OnSelectTemplate(object item, BindableObject container);
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}
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} |