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泛型类和筛选

generics linq c#

-1

r3plica · 技术社区 · 7 年前

我有一个通用类:

public class DataProvider<T> where T : class
{
    private readonly IService<T> _service;
    public DataProvider(IService<T> service) => _service = service;

    public IQueryable<T> List(params string[] includes) => _service.List(includes);
}

现在我想根据任何查询字符串参数筛选结果。例如,我想返回包含单词“special”但用于特定字段的项。查询字符串可能如下所示:

?title=特殊

我想用linq来过滤结果,但我不确定这是否可能。我换了我的列表方法如下:

public IQueryable<T> List(HttpRequestMessage request, params string[] includes)
{
    var queryString = request.GetQueryNameValuePairs();
    var models = _service.List(includes);
    // TODO: Do a contains linq query
}

有可能做这样的查找吗?或者我必须将泛型类型更改为如下类:

public class DataProvider<T> where T : Availability
{
    private readonly IService<T> _service;
    public DataProvider(IService<T> service) => _service = service;

    public IQueryable<T> List(HttpRequestMessage request, params string[] includes)
    {
        var queryString = request.GetQueryNameValuePairs();
        var models = _service.List(includes);
        // TODO: Do a contains linq query
    }
}

即使如此,我如何动态地查找属性? 我有这样的经历:

foreach (var item in queryString)
    models = models.Where(m => m.GetType().GetProperty(item.Key).GetValue(m).ToString().Contains(item.Value));

有人知道怎么做吗?

1 回复 | 直到 7 年前

r3plica 7 年前

使用dynamic linq,我能够做到:

public class DataProvider<T> where T : class
{
    private readonly IService<T> _service;
    public DataProvider(IService<T> service) => _service = service;

    public IQueryable<T> List(HttpRequestMessage request)
    {
        var queryString = request.GetQueryNameValuePairs();
        var models = _service.List();
        foreach (var item in queryString)
        {
            var query = $"{ item.Key }.ToString().Contains(\"{ item.Value }\")";
            models = models.Where(query);
        }
        return models;
    }
}

解决了我的问题

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