如何将继承的属性动态添加到 EF 数据存储区？

Question

在中，我询问并回答了如何在没有硬编码的情况下在 EF/DbSet 模型中动态导入 classes 和属性的值。我不敢相信我跌跌撞撞地摸索了足够长的时间来找出一种方法来做到这一点。但是...

它揭示了一个问题，在本地 window 中查看实例层次结构无法解决：

虽然我可以在目标 class 上动态导入数据，但它从基础 class 扩展的任何属性都失败了。上面最初的 post 在最后说明了这一点。在我们将数据导入 DataTable 后，我们的问题就出现了。我们正在遍历 DataTable 的列，使用数据库中的匹配类型来确定它们的类型（int、double 等）。

为此，一行创建了 object 我们从中查询该信息，虽然对于 Child() 属性来说一切都很好，但只要我们从 Person() 中找到一个（基数 class），它因空引用而失败。

没有re-posting整个post，我就只贴相关的位：

foreach (DataRow dr in dt.Rows) 
{
    i = 0; // I don't like to put var instantiation in a loop...
    // each drItem is the content for the row (theObj)
    foreach (string drItem in dr.ItemArray)
    {
        string entAttrName = dt.Columns[i].ToString();
        string entAttrValue = dr[i].ToString();
        // column (property) name:
        // the value of that property to load into this class' property
        // which type of data is this property? (string, int32, double...)
        // -also has data like if nullable, etc. of use in later refinements...
        TypeInfo thisTypeInfo = theObj.GetType().GetTypeInfo();
        // All details from the property to update/set:

 >>---> PropertyInfo theProp = thisTypeInfo.GetDeclaredProperty(entAttrName);

上面，最后一行未能为 theProp 分配一个有效的 object，而是将其传递给一个 null，这使我们的程序在查询时立即停止运行。

上面 link 中的示例（此代码段的来源）工作正常只要您只从 Child() class。继承的属性导致它在上面的行停止。

entAttrName 只是属性名称的字符串，取自 DataTable 之前的 header 行，并且（略过上面的某些代码行）基本上执行类似以下操作：

var aClass = u.CreateInstanceOf(dt.TableName, pathToAssembly);
DbSet dbs = ctx.Set(aClass.GetType());
var theObj = dbs.Create(aClass.GetType());
foreach (DataRow dr in dt.Rows)...
foreach (string drItem in dr.ItemArray)...
string entAttrName = dt.Columns[i].ToString();
string entAttrValue = dr[i].ToString();
TypeInfo thisTypeInfo = theObj.GetType().GetTypeInfo();
PropertyInfo theProp = thisTypeInfo.GetDeclaredProperty(entAttrName); ******
if (theProp.PropertyType.ToString() == "System.String")
{
    theProp.SetValue(theObj, (String)entAttrValue);
}
else if (theProp.PropertyType.ToString().Contains("System.Int32"))
{
    theProp.SetValue(theObj, int.Parse(entAttrValue));
} else if...

我一辈子都想不通为什么 Child()...

class Child : Person
{
    [Key]
    [Column(Order = 0)]
    public int Id { get; set; }
    public string sChildFoo { get; set; }
    public int iChildBar { get; set; }
    public double dChildBaz { get; set; }
}

...属性在该行中表现良好，但是 Person() 中的任何属性...

public abstract class Person
{
    [Key]
    public int PersonId { get; set; }
    public int PersonAge { get; set; }
    public int PersonWeight { get; set; }
    public string PersonName { get; set; }
}

...失败。这是程序的完整日志，显示了它停止的地方。异常截图在原来的post:

2016-11-08 15:03:12.9049 INFO Starting at 3:03:12 PM
2016-11-08 15:03:12.9801 INFO Created .Name: Qeququ Qequququ
2016-11-08 15:03:12.9838 INFO Created .sParentFoo: Kakikikiki
2016-11-08 15:03:13.9918 INFO wb.WorkSheets count: 2
2016-11-08 15:03:14.0007 INFO ws.Rows count: 3
2016-11-08 15:03:14.0007 INFO dt.Rows.Count: 2
2016-11-08 15:03:14.0007 INFO dt.Name: Child
2016-11-08 15:03:14.0666 INFO aClass.FullName: DynamicEFLoading.Child
2016-11-08 15:03:14.0666 INFO Creating 'dbs' object...
2016-11-08 15:03:14.0891 INFO GetType: DynamicEFLoading.Child
2016-11-08 15:03:14.0963 INFO ================= row ==================================
2016-11-08 15:03:14.0963 INFO ================= col 0 
2016-11-08 15:03:14.1105 INFO [0] Item: sChildFoo
2016-11-08 15:03:14.1105 INFO [0] Value: Norwich
2016-11-08 15:03:14.1105 INFO theProp.DeclaringType.FullName of attr: DynamicEFLoading.Child
2016-11-08 15:03:14.1265 INFO theProp.GetSetMethod(true).ToString() of attr: Void set_sChildFoo(System.String)
2016-11-08 15:03:14.1265 INFO theProp.GetType().ToString() of attr: System.Reflection.RuntimePropertyInfo
2016-11-08 15:03:14.1265 INFO theProp.Name of attr: sChildFoo
2016-11-08 15:03:14.1424 INFO theProp.PropertyType.ToString() of attr: System.String
2016-11-08 15:03:14.1424 INFO theProp.ReflectedType.ToString() of attr: DynamicEFLoading.Child
2016-11-08 15:03:14.1424 INFO theProp.ReflectedType.ToString() of attr: System.Void
2016-11-08 15:03:14.1557 DEBUG Set System.String value: Norwich
2016-11-08 15:03:14.1557 INFO ================= col 1 
2016-11-08 15:03:14.1557 INFO [1] Item: iChildBar
2016-11-08 15:03:14.1780 INFO [1] Value: 29884
2016-11-08 15:03:14.1780 INFO theProp.DeclaringType.FullName of attr: DynamicEFLoading.Child
2016-11-08 15:03:14.1919 INFO theProp.GetSetMethod(true).ToString() of attr: Void set_iChildBar(Int32)
2016-11-08 15:03:14.2113 INFO theProp.GetType().ToString() of attr: System.Reflection.RuntimePropertyInfo
2016-11-08 15:03:14.2113 INFO theProp.Name of attr: iChildBar
2016-11-08 15:03:14.2233 INFO theProp.PropertyType.ToString() of attr: System.Int32
2016-11-08 15:03:14.2368 INFO theProp.ReflectedType.ToString() of attr: DynamicEFLoading.Child
2016-11-08 15:03:14.2368 INFO theProp.ReflectedType.ToString() of attr: System.Void
2016-11-08 15:03:14.2607 DEBUG Set System.Int32 value: 29884
2016-11-08 15:03:14.2657 INFO ================= col 2 
2016-11-08 15:03:14.2851 INFO [2] Item: dChildBaz
2016-11-08 15:03:14.2978 INFO [2] Value: 1.2
2016-11-08 15:03:14.3184 INFO theProp.DeclaringType.FullName of attr: DynamicEFLoading.Child
2016-11-08 15:03:14.3305 INFO theProp.GetSetMethod(true).ToString() of attr: Void set_dChildBaz(Double)
2016-11-08 15:03:14.3305 INFO theProp.GetType().ToString() of attr: System.Reflection.RuntimePropertyInfo
2016-11-08 15:03:14.3457 INFO theProp.Name of attr: dChildBaz
2016-11-08 15:03:14.3682 INFO theProp.PropertyType.ToString() of attr: System.Double
2016-11-08 15:03:14.3910 INFO theProp.ReflectedType.ToString() of attr: DynamicEFLoading.Child
2016-11-08 15:03:14.4098 INFO theProp.ReflectedType.ToString() of attr: System.Void
2016-11-08 15:03:14.4098 DEBUG Set System.Double value: 1.2
2016-11-08 15:03:14.4098 INFO ================= col 3 
2016-11-08 15:03:14.4382 INFO [3] Item: PersonAge
2016-11-08 15:03:14.4609 INFO [3] Value: 34

完整的工作 example-with 这个 failure-see 。

============================================= ==============================

Answer 1

thisTypeInfo.GetDeclaredProperty 获取类型本身声明的属性，而不是其超类型。使用 thisTypeInfo.GetProperty。或者只是

theObj.GetType().GetProperty(entAttrName);

如何将继承的属性动态添加到 EF 数据存储区？

How can I dynamically add inherited properties to EF datastore?

c#

entity-framework

system.reflection