您好,我想创建一个动态搜索查询,使用具有来自 URI 的值的实体作为搜索字段。
下面的代码有效,但我必须搜索的一些表有超过 200 个字段,我想创建一些东西来获取属性名称并允许我在上面搜索。
它也可以有多个搜索选项,例如姓氏、名字和出生日期
queryable = queryable.Where(x => x.<PROPERTY.NAME>.Contains(query.<PROPERTY.NAME>));
这可能吗?
到目前为止,这是我的代码。
public List<EMPLOYEE> Get([FromUri] EMPLOYEE query)
{
List<EMPLOYEE> emps = new List<EMPLOYEE>();
var db = AuthHandler.Ent;
var queryable = db.EMPLOYEES.AsExpandable();
foreach (var prop in query.GetType().GetProperties())
{
if (prop.GetValue(query, null) != null)
{
switch (prop.Name)
{
case "EMP_CREATIONDATE":
queryable = queryable.Where(x => x.EMP_CREATIONDATE.Equals(query.EMP_CREATIONDATE));
break;
case "EMP_SURNAME":
queryable = queryable.Where(x => x.EMP_SURNAME.Contains(query.EMP_SURNAME));
break;
case "EMP_GIVENNAMES":
queryable = queryable.Where(x => x.EMP_GIVENNAMES.Contains(query.EMP_GIVENNAMES));
break;
}
queryable = queryable.Where(x => x.EMP_SURNAME.Contains(query.EMP_SURNAME));
}
}
emps = queryable.ToList();
return emps;
}
最佳答案
我将使用这样的谓词构建器
public static class PredicateBuilder
{
public static Expression<Func<T, bool>> True<T>() { return f => true; }
public static Expression<Func<T, bool>> False<T>() { return f => false; }
public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expr1,
Expression<Func<T, bool>> expr2)
{
var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>());
return Expression.Lambda<Func<T, bool>>
(Expression.OrElse(expr1.Body, invokedExpr), expr1.Parameters);
}
public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> expr1,
Expression<Func<T, bool>> expr2)
{
var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>());
return Expression.Lambda<Func<T, bool>>
(Expression.AndAlso(expr1.Body, invokedExpr), expr1.Parameters);
}
}
然后像这样使用它:
public IQueryable<Customer> GetCustomers(CustomerOrderSearchParameters parameters)
{
context.Database.Log = s => System.Diagnostics.Debug.WriteLine(s);
var predicate = PredicateBuilder.True<Customer>();
if (!string.IsNullOrEmpty(parameters.FirstName))
{
predicate = predicate.And(x => x.FirstName.Contains(parameters.FirstName));
}
if (!string.IsNullOrEmpty(parameters.LastName))
{
predicate = predicate.And(x => x.LastName.Contains(parameters.LastName));
}
if (!string.IsNullOrEmpty(parameters.Email))
{
predicate = predicate.And(x => x.email.Contains(parameters.Email));
}
if (!string.IsNullOrEmpty(parameters.PhoneNumber))
{
predicate = predicate.And(x => x.MobilePhone.Contains(parameters.PhoneNumber) || x.HomePhone.Contains(parameters.PhoneNumber));
}
if (parameters.BrandID != null)
{
predicate = predicate.And(x => x.Logins.Where(l => l.BrandID == parameters.BrandID).Any());
}
if (parameters.ShowNoOrders == true)
{
predicate = predicate.And(x => x.Orders.Where(o => o.CustomerID != x.CustomerID).Any());
}
return context.Customers.AsExpandable().Where(predicate);
}
此外,CustomerOrderSearchParameters
只是一个简单参数列表(等同于您将从查询中获得的参数)
关于c# - 使用传入的参数作为搜索字段使用 Entity Framework Web API 创建动态搜索查询,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46048118/