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这是关于 InvalidOperationException 的问题,消息未映射类成员X。
对于框架版本3.5的每个LinqToSql实体,我们的系统之一具有相同的基本实体。
我遇到了一个非常奇怪的问题,我开始对此进行研究。我做了一个很小的项目,以便能够更轻松地定位问题。
实体基类
public abstract class EntityBase
{
public virtual long ID { get; set; }
}
[Database(Name = "TestDatabase")]
public class EntitiesDataContext : DataContext
{
public EntitiesDataContext() :
base(Settings.Default.TestDatabaseConnectionString, new AttributeMappingSource())
{
}
}
[Table(Name = "dbo.MyEntity")]
public class MyEntity : EntityBase
{
private long _EntityID;
[Column(Name = "EntityID", Storage = "_EntityID")]
public override long ID
{
get { return _EntityID; }
set { _EntityID = value; }
}
[Column] public string Title;
}
using (var ctx = new EntitiesDataContext())
{
//statement
}
GetTable<MyEntity>().
var result = ctx.GetTable().Where(i => i.ID == 2).FirstOrDefault();
var result = ctx.GetTable().FirstOrDefault(i => i.ID == 2);
var result = ctx.GetTable().FirstOrDefault(i => i.ID.Equals(2));
var result = ctx.GetTable().Where(i => true).FirstOrDefault(i => i.ID == 2);
var result = ctx.GetTable().Where(i => i.ID == 2).FirstOrDefault();
var result = ctx.GetTable().Where(i => i.ID == 2).FirstOrDefault()
var result = ctx.GetTable().Where(i => i.ID.Equals(2)).FirstOrDefault();
var result = ctx.GetTable().FirstOrDefault(i => i.ID == 2);
var result = ctx.GetTable().FirstOrDefault(i => i.ID.Equals(2));
ctx.GetTable().Where(i => true).FirstOrDefault(i => i.ID == 2);
var result = ctx.GetTable().Where(i => true).FirstOrDefault(i => i.ID == 2);
var result = ctx.GetTable().Where(i => i.ID == 2).Select(i => i.Title).FirstOrDefault();
var result = ctx.GetTable().FirstOrDefault();
Where(i => true).FirstOrDefault(i => i.ID == 2)
FirstOrDefault(i => i.ID == 2)
public void WithEquals(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().FirstOrDefault(i => i.ID.Equals(2));
}
public void WithFakeWhereAndOperator(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().Where(i => true).FirstOrDefault(i => i.ID == 2);
}
public void WithOperator(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().FirstOrDefault(i => i.ID == 2);
}
public void WithOperatorSelect(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().Where(i => i.ID == 2).Select(i => i).FirstOrDefault();
}
public void WithOperatorAndWhere(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().Where(i => i.ID == 2).FirstOrDefault();
}
.method public hidebysig instance void WithOperator(class LinqToSqlTest.EntitiesDataContext ctx) cil managed
{
.maxstack 5
.locals init (
[0] class [System.Core]System.Linq.Expressions.ParameterExpression CS$0$0000,
[1] class [System.Core]System.Linq.Expressions.ParameterExpression[] CS$0$0001)
L_0000: nop
L_0001: ldarg.1
L_0002: callvirt instance class [System.Data.Linq]System.Data.Linq.Table`1<!!0> [System.Data.Linq]System.Data.Linq.DataContext::GetTable<class LinqToSqlTest.MyEntity>()
L_0007: ldtoken LinqToSqlTest.MyEntity
L_000c: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0011: ldstr "i"
L_0016: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_001b: stloc.0
L_001c: ldloc.0
L_001d: ldtoken instance int64 LinqToSqlTest.EntityBase::get_ID()
L_0022: call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle(valuetype [mscorlib]System.RuntimeMethodHandle)
L_0027: castclass [mscorlib]System.Reflection.MethodInfo
L_002c: call class [System.Core]System.Linq.Expressions.MemberExpression [System.Core]System.Linq.Expressions.Expression::Property(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo)
L_0031: ldc.i4.2
L_0032: conv.i8
L_0033: box int64
L_0038: ldtoken int64
L_003d: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0042: call class [System.Core]System.Linq.Expressions.ConstantExpression [System.Core]System.Linq.Expressions.Expression::Constant(object, class [mscorlib]System.Type)
L_0047: call class [System.Core]System.Linq.Expressions.BinaryExpression [System.Core]System.Linq.Expressions.Expression::Equal(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.Expression)
L_004c: ldc.i4.1
L_004d: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_0052: stloc.1
L_0053: ldloc.1
L_0054: ldc.i4.0
L_0055: ldloc.0
L_0056: stelem.ref
L_0057: ldloc.1
L_0058: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, bool>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_005d: call !!0 [System.Core]System.Linq.Queryable::FirstOrDefault<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, bool>>)
L_0062: pop
L_0063: ret
}
.method public hidebysig instance void WithFakeWhereAndOperator(class LinqToSqlTest.EntitiesDataContext ctx) cil managed
{
.maxstack 5
.locals init (
[0] class [System.Core]System.Linq.Expressions.ParameterExpression CS$0$0000,
[1] class [System.Core]System.Linq.Expressions.ParameterExpression[] CS$0$0001)
L_0000: nop
L_0001: ldarg.1
L_0002: callvirt instance class [System.Data.Linq]System.Data.Linq.Table`1<!!0> [System.Data.Linq]System.Data.Linq.DataContext::GetTable<class LinqToSqlTest.MyEntity>()
L_0007: ldtoken LinqToSqlTest.MyEntity
L_000c: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0011: ldstr "i"
L_0016: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_001b: stloc.0
L_001c: ldc.i4.1
L_001d: box bool
L_0022: ldtoken bool
L_0027: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_002c: call class [System.Core]System.Linq.Expressions.ConstantExpression [System.Core]System.Linq.Expressions.Expression::Constant(object, class [mscorlib]System.Type)
L_0031: ldc.i4.1
L_0032: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_0037: stloc.1
L_0038: ldloc.1
L_0039: ldc.i4.0
L_003a: ldloc.0
L_003b: stelem.ref
L_003c: ldloc.1
L_003d: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, bool>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_0042: call class [System.Core]System.Linq.IQueryable`1<!!0> [System.Core]System.Linq.Queryable::Where<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, bool>>)
L_0047: ldtoken LinqToSqlTest.MyEntity
L_004c: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0051: ldstr "i"
L_0056: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_005b: stloc.0
L_005c: ldloc.0
L_005d: ldtoken instance int64 LinqToSqlTest.EntityBase::get_ID()
L_0062: call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle(valuetype [mscorlib]System.RuntimeMethodHandle)
L_0067: castclass [mscorlib]System.Reflection.MethodInfo
L_006c: call class [System.Core]System.Linq.Expressions.MemberExpression [System.Core]System.Linq.Expressions.Expression::Property(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo)
L_0071: ldc.i4.2
L_0072: conv.i8
L_0073: box int64
L_0078: ldtoken int64
L_007d: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0082: call class [System.Core]System.Linq.Expressions.ConstantExpression [System.Core]System.Linq.Expressions.Expression::Constant(object, class [mscorlib]System.Type)
L_0087: call class [System.Core]System.Linq.Expressions.BinaryExpression [System.Core]System.Linq.Expressions.Expression::Equal(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.Expression)
L_008c: ldc.i4.1
L_008d: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_0092: stloc.1
L_0093: ldloc.1
L_0094: ldc.i4.0
L_0095: ldloc.0
L_0096: stelem.ref
L_0097: ldloc.1
L_0098: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, bool>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_009d: call !!0 [System.Core]System.Linq.Queryable::FirstOrDefault<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, bool>>)
L_00a2: pop
L_00a3: ret
}
.method public hidebysig instance void WithEquals(class LinqToSqlTest.EntitiesDataContext ctx) cil managed
{
.maxstack 7
.locals init (
[0] class [System.Core]System.Linq.Expressions.ParameterExpression CS$0$0000,
[1] class [System.Core]System.Linq.Expressions.Expression[] CS$0$0001,
[2] class [System.Core]System.Linq.Expressions.ParameterExpression[] CS$0$0002)
L_0000: nop
L_0001: ldarg.1
L_0002: callvirt instance class [System.Data.Linq]System.Data.Linq.Table`1<!!0> [System.Data.Linq]System.Data.Linq.DataContext::GetTable<class LinqToSqlTest.MyEntity>()
L_0007: ldtoken LinqToSqlTest.MyEntity
L_000c: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0011: ldstr "i"
L_0016: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_001b: stloc.0
L_001c: ldloc.0
L_001d: ldtoken instance int64 LinqToSqlTest.EntityBase::get_ID()
L_0022: call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle(valuetype [mscorlib]System.RuntimeMethodHandle)
L_0027: castclass [mscorlib]System.Reflection.MethodInfo
L_002c: call class [System.Core]System.Linq.Expressions.MemberExpression [System.Core]System.Linq.Expressions.Expression::Property(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo)
L_0031: ldtoken instance bool [mscorlib]System.Int64::Equals(int64)
L_0036: call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle(valuetype [mscorlib]System.RuntimeMethodHandle)
L_003b: castclass [mscorlib]System.Reflection.MethodInfo
L_0040: ldc.i4.1
L_0041: newarr [System.Core]System.Linq.Expressions.Expression
L_0046: stloc.1
L_0047: ldloc.1
L_0048: ldc.i4.0
L_0049: ldc.i4.2
L_004a: conv.i8
L_004b: box int64
L_0050: ldtoken int64
L_0055: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_005a: call class [System.Core]System.Linq.Expressions.ConstantExpression [System.Core]System.Linq.Expressions.Expression::Constant(object, class [mscorlib]System.Type)
L_005f: stelem.ref
L_0060: ldloc.1
L_0061: call class [System.Core]System.Linq.Expressions.MethodCallExpression [System.Core]System.Linq.Expressions.Expression::Call(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo, class [System.Core]System.Linq.Expressions.Expression[])
L_0066: ldc.i4.1
L_0067: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_006c: stloc.2
L_006d: ldloc.2
L_006e: ldc.i4.0
L_006f: ldloc.0
L_0070: stelem.ref
L_0071: ldloc.2
L_0072: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, bool>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_0077: call !!0 [System.Core]System.Linq.Queryable::FirstOrDefault<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, bool>>)
L_007c: pop
L_007d: ret
}
[System.Core]System.Linq.Expressions.Expression[]
call class [System.Core]System.Linq.Expressions.BinaryExpression [System.Core]System.Linq.Expressions.Expression::Equal(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.Expression)
call class [System.Core]System.Linq.Expressions.MethodCallExpression [System.Core]System.Linq.Expressions.Expression::Call(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo, class [System.Core]System.Linq.Expressions.Expression[])
public void WithOperatorSelect(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().Where(i => i.ID == 2).Select(i => i).FirstOrDefault();
}
public void WithOperatorAndWhere(EntitiesDataContext ctx)
{
ctx.GetTable<MyEntity>().Where(i => i.ID == 2).FirstOrDefault();
}
.method public hidebysig instance void WithOperatorSelect(class LinqToSqlTest.EntitiesDataContext ctx) cil managed
{
.maxstack 5
.locals init (
[0] class [System.Core]System.Linq.Expressions.ParameterExpression CS$0$0000,
[1] class [System.Core]System.Linq.Expressions.ParameterExpression[] CS$0$0001)
L_0000: nop
L_0001: ldarg.1
L_0002: callvirt instance class [System.Data.Linq]System.Data.Linq.Table`1<!!0> [System.Data.Linq]System.Data.Linq.DataContext::GetTable<class LinqToSqlTest.MyEntity>()
L_0007: ldtoken LinqToSqlTest.MyEntity
L_000c: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0011: ldstr "i"
L_0016: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_001b: stloc.0
L_001c: ldloc.0
L_001d: ldtoken instance int64 LinqToSqlTest.EntityBase::get_ID()
L_0022: call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle(valuetype [mscorlib]System.RuntimeMethodHandle)
L_0027: castclass [mscorlib]System.Reflection.MethodInfo
L_002c: call class [System.Core]System.Linq.Expressions.MemberExpression [System.Core]System.Linq.Expressions.Expression::Property(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo)
L_0031: ldc.i4.2
L_0032: conv.i8
L_0033: box int64
L_0038: ldtoken int64
L_003d: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0042: call class [System.Core]System.Linq.Expressions.ConstantExpression [System.Core]System.Linq.Expressions.Expression::Constant(object, class [mscorlib]System.Type)
L_0047: call class [System.Core]System.Linq.Expressions.BinaryExpression [System.Core]System.Linq.Expressions.Expression::Equal(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.Expression)
L_004c: ldc.i4.1
L_004d: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_0052: stloc.1
L_0053: ldloc.1
L_0054: ldc.i4.0
L_0055: ldloc.0
L_0056: stelem.ref
L_0057: ldloc.1
L_0058: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, bool>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_005d: call class [System.Core]System.Linq.IQueryable`1<!!0> [System.Core]System.Linq.Queryable::Where<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, bool>>)
L_0062: ldtoken LinqToSqlTest.MyEntity
L_0067: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_006c: ldstr "i"
L_0071: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_0076: stloc.0
L_0077: ldloc.0
L_0078: ldc.i4.1
L_0079: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_007e: stloc.1
L_007f: ldloc.1
L_0080: ldc.i4.0
L_0081: ldloc.0
L_0082: stelem.ref
L_0083: ldloc.1
L_0084: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, class LinqToSqlTest.MyEntity>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_0089: call class [System.Core]System.Linq.IQueryable`1<!!1> [System.Core]System.Linq.Queryable::Select<class LinqToSqlTest.MyEntity, class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, !!1>>)
L_008e: call !!0 [System.Core]System.Linq.Queryable::FirstOrDefault<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>)
L_0093: pop
L_0094: ret
}
.method public hidebysig instance void WithOperatorAndWhere(class LinqToSqlTest.EntitiesDataContext ctx) cil managed
{
.maxstack 5
.locals init (
[0] class [System.Core]System.Linq.Expressions.ParameterExpression CS$0$0000,
[1] class [System.Core]System.Linq.Expressions.ParameterExpression[] CS$0$0001)
L_0000: nop
L_0001: ldarg.1
L_0002: callvirt instance class [System.Data.Linq]System.Data.Linq.Table`1<!!0> [System.Data.Linq]System.Data.Linq.DataContext::GetTable<class LinqToSqlTest.MyEntity>()
L_0007: ldtoken LinqToSqlTest.MyEntity
L_000c: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0011: ldstr "i"
L_0016: call class [System.Core]System.Linq.Expressions.ParameterExpression [System.Core]System.Linq.Expressions.Expression::Parameter(class [mscorlib]System.Type, string)
L_001b: stloc.0
L_001c: ldloc.0
L_001d: ldtoken instance int64 LinqToSqlTest.EntityBase::get_ID()
L_0022: call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle(valuetype [mscorlib]System.RuntimeMethodHandle)
L_0027: castclass [mscorlib]System.Reflection.MethodInfo
L_002c: call class [System.Core]System.Linq.Expressions.MemberExpression [System.Core]System.Linq.Expressions.Expression::Property(class [System.Core]System.Linq.Expressions.Expression, class [mscorlib]System.Reflection.MethodInfo)
L_0031: ldc.i4.2
L_0032: conv.i8
L_0033: box int64
L_0038: ldtoken int64
L_003d: call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle(valuetype [mscorlib]System.RuntimeTypeHandle)
L_0042: call class [System.Core]System.Linq.Expressions.ConstantExpression [System.Core]System.Linq.Expressions.Expression::Constant(object, class [mscorlib]System.Type)
L_0047: call class [System.Core]System.Linq.Expressions.BinaryExpression [System.Core]System.Linq.Expressions.Expression::Equal(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.Expression)
L_004c: ldc.i4.1
L_004d: newarr [System.Core]System.Linq.Expressions.ParameterExpression
L_0052: stloc.1
L_0053: ldloc.1
L_0054: ldc.i4.0
L_0055: ldloc.0
L_0056: stelem.ref
L_0057: ldloc.1
L_0058: call class [System.Core]System.Linq.Expressions.Expression`1<!!0> [System.Core]System.Linq.Expressions.Expression::Lambda<class [mscorlib]System.Func`2<class LinqToSqlTest.MyEntity, bool>>(class [System.Core]System.Linq.Expressions.Expression, class [System.Core]System.Linq.Expressions.ParameterExpression[])
L_005d: call class [System.Core]System.Linq.IQueryable`1<!!0> [System.Core]System.Linq.Queryable::Where<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>, class [System.Core]System.Linq.Expressions.Expression`1<class [mscorlib]System.Func`2<!!0, bool>>)
L_0062: call !!0 [System.Core]System.Linq.Queryable::FirstOrDefault<class LinqToSqlTest.MyEntity>(class [System.Core]System.Linq.IQueryable`1<!!0>)
L_0067: pop
L_0068: ret
}
最佳答案
好的,这似乎是一个已知的错误:
http://connect.microsoft.com/VisualStudio/feedback/details/394255/linq-to-sql-bug-handling-entities-with-common-base-class
它不会被修复。
相关问题:
LINQ to SQL - mapping exception when using abstract base classes
LinqToSql and abstract base classes
无论如何,谢谢弗兰克·坦那贝提斯(Frank Tzanabetis)的努力。
关于c# - 有趣的Linq to SQL通用基类行为,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/7673246/
我使用 AppFuse 创建项目已经有一段时间了。我已经知道有两种方法可以开发 DAO 和 Manager 类: GenericDao/GenericManager 方法 UniversalDao/U
很难说出这里问的是什么。这个问题是含糊的、模糊的、不完整的、过于宽泛的或修辞性的,无法以目前的形式得到合理的回答。如需帮助澄清此问题以便重新打开它,visit the help center 。 已关
在普通的单线程程序中,捕获异常只需要通过try ... catch ... finally ...代码块就可以了。那么,在并发情况下,比如在父线程中启动了子线程,如何在父线程中捕获来自子线程的异常,
假设我有一个这样的界面 interface Example { first_name: string, last_name: string, home_town: string
我已经成为 hg 用户几年了,对此我很高兴! 我必须开始一个我以前从未做过的项目。我们的想法是开发一个具有批处理模式和 GUI 的软件。 因此,批处理模式和 GUI 模式都有共同的源,但每种模式也都包
我可以在Silverlight中使用generic.xaml来设置应用程序中所有TextBlock的样式吗? 我原以为它会起作用,但它没
顶部 map 有 3 个子 map ,每个子 map 都有不同的对象。 像下面的代码,如何将通用添加到 map 顶部? Map top = new ConcurrentHashMap();
我想创建一个hashmap,其中键是接口(interface)A,值是接口(interface)B。然后我想用实现A和B的类来初始化它。是否可以使用java泛型来做到这一点? 也就是说,我想要类似的东
Enum 位于 java.lang.Enum 中,Object 位于 java.lang.Object 中>。那么,为什么 Enum 不是 Object 呢? (我收到一个java.lang.Clas
我有一种方法,check,它有两个 HashMap 作为参数。这些映射的键是 String,值是 String 或 Arraylist。 哪个是更好的解决方案: public static boole
我启动了针对iPhone的应用程序,现在我也想将其应用程序用于iPad。当我开始做iPhone项目时,即使我添加了iPad xib,它也无法正确显示,如何转换我的项目同时适用于iPhone和iPad(
这行代码(代码1)有什么区别 auto l1 = [](auto a) { static int l = 0; std::cout operator() for type const char*) 被
使用 Generic#to,我可以获得 case class 的 HList 表示: import shapeless._ case class F(x: Int, y: String) scala>
我有一个 BiDiMap 类。如何使其通用,不仅接受 String 而且接受 Object 类型的对象作为输入参数,同时保持所有原始函数正常工作。例如,我希望能够使用函数 put() 和 Object
我在编译 foreach 循环时遇到问题。我很确定这是我的泛型处理的问题,因为该错误是对象兼容性问题。我已搜索解决方案,但找不到任何可以解决该问题的内容。 这是定义 Iterable adjList
大约有 6 个 POJO 类(域实体、DTO、DMO)都具有几乎相同的字段。为了从一个对象转换为另一个对象,我传递一个对象并调用它的 getter 将其设置到另一个对象中。 private UserT
有没有什么方法可以创建一个通用的 for 循环,它可以正确地循环遍历数组或对象?我知道我可以编写以下 for 循环,但它也会遍历将添加到数组的其他属性。 for (item in x) { co
我已经有一段时间没有写js了,显然有点生疏了。试图理解以下问题。 getCurrentPosition successCallback 中的警报正确显示纬度,但最后一行警报未定义。为什么我的 clie
请帮助我,我从来没有用 xib 为 iPhone/iPad 制作过通用的 UIViewControllers。如何使用 .m 和 .h 文件以及 _iphone.xib 和 _ipad.xib 创建类
我正在尝试创建一个 createRequest 函数,我可以将其重新用于我的所有网络调用,有些需要发布 JSON 而其他则不需要,所以我正在考虑创建一个采用可选通用对象的函数;理论上是这样的: str
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