如何获取实体框架查询的参数? [英] How can I get the parameters of an Entity Framework query?

问题描述

如果我创建 IQueryable<T> 的查询，我可以调用 .ToString() 来获取将被调用的 SQL，但该 SQL 可能包含 @p__linq__0、@p__linq__1、等有没有办法从 IQueryable<T>

If I create a query of IQueryable<T>, I can call .ToString() to get the SQL that will be called, but that SQL may contain parameters like @p__linq__0, @p__linq__1, etc. Is there a way to get those parameters and their values from the IQueryable<T>

推荐答案

根据我的经验，这非常复杂，但这段代码让我明白了:

It's frustratingly complicated, in my experience, but this code got me there:

        var dbQuery = (DbQuery<T>)query;
        // get the IInternalQuery internal variable from the DbQuery object
        var iqProp = dbQuery.GetType().GetProperty("InternalQuery", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
        var iq = iqProp.GetValue(dbQuery, null);
        // get the ObjectQuery internal variable from the IInternalQuery object
        var oqProp = iq.GetType().GetProperty("ObjectQuery", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
        var objectQuery = (ObjectQuery<T>)oqProp.GetValue(iq, null);

        var sqlString = objectQuery.ToTraceString(); // this will populate the parameters collection
        foreach (var objectParam in objectQuery.Parameters)
        {
            Console.WriteLine($"{objectParam.Name} = {objectParam.Value.ToString()}");
        }

请注意，此代码仅适用于 IQueryable<T> 对象，这些对象实际上是 DbQuery<T>，由实体框架创建.如果您打算将其包装在实用方法中，则可能需要进行一些类型检查.

Note that this code only works for IQueryable<T> objects that are actually DbQuery<T>, as are created by entity framework. If you intend to wrap this in a utility method, some type checking may be in order.

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