使用linq.dynamic生成的expression后报错

[tiansfather]

错误信息是：variable '' of type 'MyEntity' referenced from scope '', but it is not defined
有什么办法可以支持？

`using FreeSql;
using FreeSql.DataAnnotations;
using System;
using System.Linq.Dynamic.Core;
using System.Linq.Expressions;

var fsql = new FreeSqlBuilder()
.UseConnectionString(DataType.MySql, "Server=localhost;Database=db;charset=utf8;user=root;password=root")
.UseAutoSyncStructure(true)
.Build();

Expression<Func<MyEntity, string>> newexp = x => x.Name;

var func = DynamicExpressionParser.ParseLambda<MyEntity, bool>(new ParsingConfig(), true, "@0(it)=="aa"", new[] { newexp });

//报错variable '' of type 'MyEntity' referenced from scope '', but it is not defined
var a = fsql.Select().Where(func).Count();

internal class MyEntity
{
[Column(IsIdentity = true)]
public int Id { get; set; }

public string Name { get; set; }

}`

[2881099]

func 具体类型是什么，#1113 这个可能有帮助

[tiansfather]

func 就是Expression<Func<MyEntity,bool>>类型，具体错误堆栈如下：
在 System.Linq.Expressions.Compiler.VariableBinder.Reference(ParameterExpression node, VariableStorageKind storage)
在 System.Linq.Expressions.Compiler.VariableBinder.VisitParameter(ParameterExpression node)
在 System.Linq.Expressions.ParameterExpression.Accept(ExpressionVisitor visitor)
在 System.Linq.Expressions.Compiler.VariableBinder.Visit(Expression node)
在 System.Linq.Expressions.Compiler.VariableBinder.VisitInvocation(InvocationExpression node)
在 System.Linq.Expressions.InvocationExpression.Accept(ExpressionVisitor visitor)
在 System.Linq.Expressions.Compiler.VariableBinder.Visit(Expression node)
在 System.Linq.Expressions.ExpressionVisitor.Visit(ReadOnlyCollection1 nodes) 在 System.Linq.Expressions.Compiler.VariableBinder.VisitLambda[T](Expression1 node)
在 System.Linq.Expressions.Expression`1.Accept(ExpressionVisitor visitor)
在 System.Linq.Expressions.Compiler.VariableBinder.Visit(Expression node)
在 System.Linq.Expressions.Compiler.LambdaCompiler.Compile(LambdaExpression lambda)
在 System.Linq.Expressions.LambdaExpression.Compile()
在 FreeSql.Internal.CommonExpression.ExpressionLambdaToSql(Expression exp, ExpTSC tsc) 在 C:\Users\28810\Desktop\github\FreeSql\FreeSql\Internal\CommonExpression.cs 中: 第 926 行

这种方式生成的expression在ef core中是可以使用的，但在freesql中好像解析不了。

测试源码在https://gitee.com/tiansfather/fortest.git，您有空了麻烦帮忙看看

DynamicFilterInfo 还没用过，我去看看

[2881099]

fsql.Aop.ParseExpression 解决办法如下：（v3.2.685 版本会集成）

using FreeSql;
using FreeSql.DataAnnotations;
using System;
using System.Linq.Dynamic.Core;
using System.Linq.Expressions;

var fsql = new FreeSqlBuilder()
                 .UseConnectionString(DataType.Sqlite, "data source=:memory:")
                 .UseAutoSyncStructure(true)
                 .UseNoneCommandParameter(true)
                 .UseMonitorCommand(cmd => Console.WriteLine(cmd.CommandText))
                 .Build();

fsql.Aop.ParseExpression += (_, e) =>
{
    if (e.Expression.NodeType == ExpressionType.Invoke && 
        e.Expression is InvocationExpression invokeExp)
    {
        var replaceVistor = new FreeSql.Internal.CommonExpression.ReplaceVisitor();
        var replaceExp = invokeExp.Expression;
        var lambdaExp = replaceExp as LambdaExpression;
        var len = Math.Min(invokeExp.Arguments.Count, lambdaExp.Parameters.Count);
        for (var a = 0; a < len; a++)
            replaceExp = replaceVistor.Modify(replaceExp, lambdaExp.Parameters[a], invokeExp.Arguments[a]);
        e.Result = e.FreeParse(replaceExp);
    }
};

//定义一个expression
Expression<Func<MyEntity, string>> newexp = x => x.Name;

//使用System.Linq.Dynamic.Core 包装成另一个expression
var func = DynamicExpressionParser.ParseLambda<MyEntity, bool>(new ParsingConfig(), true, "@0(it)==\"aa\"", new[] { newexp });

//报错variable '' of type 'MyEntity' referenced from scope '', but it is not defined
var a = fsql.Select<MyEntity>().Where(func).Count();

internal class MyEntity
{
    [Column(IsIdentity = true)]
    public int Id { get; set; }

    public string Name { get; set; }
}

[2881099]

v3.2.685 已发布

[tiansfather]

感谢