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[英]Entity Framework, Generic loading of related entities with a where condition
[英]Generic where condition in Entity Framework Core
我正在构建一个使用工作单元设计模式的Web API应用程序。 我用搜索功能创建了一个存储库:
public IQueryable<User> Search(SearchUserViewModel parameter)
{
// Find all user from database
var users = GetAll();
// Id has been defined.
if (parameter.Id != null)
users = users.Where(x => x.Id == parameter.Id.Value);
// Email has been defined.
if (parameter.Email != null && !string.IsNullOrWhiteSpace(parameter.Email.Text))
{
var emailSearch = parameter.Email;
switch (emailSearch.Mode)
{
case TextSearchMode.ContainIgnoreCase:
// TODO: Recheck.
users = users.Where(x => x.Email.Contains(emailSearch.Text));
break;
case TextSearchMode.Equal:
users = users.Where(x => x.Email.Equals(emailSearch.Text));
break;
case TextSearchMode.EqualIgnoreCase:
users = users.Where(x => x.Email.Equals(emailSearch.Text, StringComparison.OrdinalIgnoreCase));
break;
default:
users = users.Where(x => x.Email.Contains(emailSearch.Text));
break;
}
}
if (parameter.Password != null && !string.IsNullOrWhiteSpace(parameter.Password.Text))
{
var passwordSearch = parameter.Password;
switch (passwordSearch.Mode)
{
case TextSearchMode.ContainIgnoreCase:
// TODO: Recheck.
users = users.Where(x => x.Email.Contains(passwordSearch.Text));
break;
case TextSearchMode.Equal:
users = users.Where(x => x.Email.Equals(passwordSearch.Text));
break;
case TextSearchMode.EqualIgnoreCase:
users = users.Where(x => x.Email.Equals(passwordSearch.Text, StringComparison.OrdinalIgnoreCase));
break;
default:
users = users.Where(x => x.Email.Contains(passwordSearch.Text));
break;
}
}
return users;
}
带有枚举:
public class TextSearch
{
/// <summary>
/// Comparision mode.
/// </summary>
public TextSearchMode Mode { get; set; }
/// <summary>
/// Text which needs searching.
/// </summary>
public string Text { get; set; }
}
搜索功能目前运行良好。 但是我想减少代码。 我想知道是否有一种方法可以创建像这样的函数:
private IQueryable<T> SearchPropertyText(IQueryable<T> records, string propertyName, TextSearchMode mode)
{
switch (mode)
{
case Equal:
// TODO:
case EqualIgnoreCase:
// TODO:
default:
// TODO
}
return records;
}
然后,我可以使用如下功能:
users = SearchPropertyText(users, user.Email, emailSearch.Mode)
正如您在上面的代码中看到的那样,TextSearchMode枚举中列出了一些文本搜索模式,基于模式,我将使用Equal,EqualIgnoreCase,Contains,...搜索属性。
我正在考虑泛型函数,但现在还不知道如何创建它。
有人可以帮我吗?
而不是传递user.Email,您需要传递一个Func,该Func定义如何从任何用户获取所需的属性。 另外, TextSearchMode
传递TextSearchMode
,不如传递TextSearch
对象,因为还需要Text属性来执行搜索。 这是一个代码示例:
private IQueryable<T> SearchPropertyText(IQueryable<T> records, Func<T, string> property, TextSearch search)
{
switch (search.Mode)
{
case TextSearchMode.ContainIgnoreCase:
records = records.Where(x => property(x).Contains(search.Text));
break;
case TextSearchMode.Equal:
records = records.Where(x => property(x).Equals(search.Text));
break;
case TextSearchMode.EqualIgnoreCase:
records = records.Where(x => property(x).Equals(search.Text, StringComparison.OrdinalIgnoreCase));
break;
default:
records = records.Where(x => property(x).Contains(search.Text));
break;
}
return records;
}
然后像这样使用它:
users = SearchPropertyText(users, user => user.Email, emailSearch);
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