如何从一组项目中选择特定项目？

Question

我正在使用Windows Phone的DataBoundApp模板，并且在模板中，selectedIndex值从MainPage传递到DetailsPage以定义数据上下文......如下所示：

    // When page is navigated to set data context to selected item in list
    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        string selectedIndex = "";
        if (NavigationContext.QueryString.TryGetValue("selectedItem", out selectedIndex))
        {
            int index = int.Parse(selectedIndex);
            DataContext = App.ViewModel.Items[index];
        }
    }

这是设置数据上下文的唯一方法，还是可以选择具有特定值的项目，例如，我想将数据上下文设置为具有LineOne =“runtime seven”值的项目...

我该如何设定？

编辑：这些是viewmodel项目

    public void LoadData()
    {
        // Sample data; replace with real data
        this.Items.Add(new ItemViewModel() { LineOne = "runtime one", LineTwo = "Maecenas praesent accumsan bibendum", LineThree = "Facilisi faucibus habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime two", LineTwo = "Dictumst eleifend facilisi faucibus", LineThree = "Suscipit torquent ultrices vehicula volutpat maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime three", LineTwo = "Habitant inceptos interdum lobortis", LineThree = "Habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu suscipit torquent" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime four", LineTwo = "Nascetur pharetra placerat pulvinar", LineThree = "Ultrices vehicula volutpat maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus habitant inceptos" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime five", LineTwo = "Maecenas praesent accumsan bibendum", LineThree = "Maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus habitant inceptos interdum lobortis nascetur" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime six", LineTwo = "Dictumst eleifend facilisi faucibus", LineThree = "Pharetra placerat pulvinar sagittis senectus sociosqu suscipit torquent ultrices vehicula volutpat maecenas praesent" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime seven", LineTwo = "Habitant inceptos interdum lobortis", LineThree = "Accumsan bibendum dictumst eleifend facilisi faucibus habitant inceptos interdum lobortis nascetur pharetra placerat" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime eight", LineTwo = "Nascetur pharetra placerat pulvinar", LineThree = "Pulvinar sagittis senectus sociosqu suscipit torquent ultrices vehicula volutpat maecenas praesent accumsan bibendum" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime nine", LineTwo = "Maecenas praesent accumsan bibendum", LineThree = "Facilisi faucibus habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime ten", LineTwo = "Dictumst eleifend facilisi faucibus", LineThree = "Suscipit torquent ultrices vehicula volutpat maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime eleven", LineTwo = "Habitant inceptos interdum lobortis", LineThree = "Habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu suscipit torquent" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime twelve", LineTwo = "Nascetur pharetra placerat pulvinar", LineThree = "Ultrices vehicula volutpat maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus habitant inceptos" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime thirteen", LineTwo = "Maecenas praesent accumsan bibendum", LineThree = "Maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus habitant inceptos interdum lobortis nascetur" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime fourteen", LineTwo = "Dictumst eleifend facilisi faucibus", LineThree = "Pharetra placerat pulvinar sagittis senectus sociosqu suscipit torquent ultrices vehicula volutpat maecenas praesent" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime fifteen", LineTwo = "Habitant inceptos interdum lobortis", LineThree = "Accumsan bibendum dictumst eleifend facilisi faucibus habitant inceptos interdum lobortis nascetur pharetra placerat" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime sixteen", LineTwo = "Nascetur pharetra placerat pulvinar", LineThree = "Pulvinar sagittis senectus sociosqu suscipit torquent ultrices vehicula volutpat maecenas praesent accumsan bibendum" });

        this.IsDataLoaded = true;
    }

我不想按项目的索引号设置数据上下文，而是按特定项目值

设置

Answer 1

只要您可以为您要搜索的值赋值，下面的内容就可以了。

string value = "runtime seven";

DataContext = App.ViewModel.Items.FirstOrDefault(item => item.LineOne == value);