LambadaExpressionExtensions.cs
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using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
namespace System.Linq.Expressions
{
public static partial class LambadaExpressionExtensions
{
static LambdaExpression InternalAndOrExpression(bool condition, LambdaExpression exp1, LambdaExpression exp2, bool isAndAlso)
{
if (condition == false) return exp1;
if (exp1 == null) return exp2;
if (exp2 == null) return exp1;
var newParameters = exp1.Parameters.Select((a, b) => Expression.Parameter(a.Type, a.Name /*$"new{b}"*/)).ToArray();
var left = new NewExpressionVisitor(newParameters, exp1.Parameters.ToArray()).Replace(exp1.Body);
var right = new NewExpressionVisitor(newParameters, exp2.Parameters.ToArray()).Replace(exp2.Body);
var body = isAndAlso ? Expression.AndAlso(left, right) : Expression.OrElse(left, right);
return Expression.Lambda(exp1.Type, body, newParameters);
}
static LambdaExpression InternalNotExpression(bool condition, LambdaExpression exp)
{
if (condition == false) return exp;
if (exp == null) return null;
var newParameters = exp.Parameters.Select((a, b) => Expression.Parameter(a.Type, a.Name /*$"new{b}"*/)).ToArray();
var body = Expression.Not(exp.Body);
return Expression.Lambda(exp.Type, body, newParameters);
}
#region T1
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, bool>> And<T1>(this Expression<Func<T1, bool>> exp1, Expression<Func<T1, bool>> exp2) => And(exp1, true, exp2);
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, bool>> And<T1>(this Expression<Func<T1, bool>> exp1, bool condition, Expression<Func<T1, bool>> exp2) => (Expression<Func<T1, bool>>)InternalAndOrExpression(condition, exp1, exp2, true);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, bool>> Or<T1>(this Expression<Func<T1, bool>> exp1, Expression<Func<T1, bool>> exp2) => Or(exp1, true, exp2);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, bool>> Or<T1>(this Expression<Func<T1, bool>> exp1, bool condition, Expression<Func<T1, bool>> exp2) => (Expression<Func<T1, bool>>)InternalAndOrExpression(condition, exp1, exp2, false);
/// <summary>
/// 将 lambda 表达式取反
/// </summary>
/// <param name="exp"></param>
/// <param name="condition">true 时生效</param>
/// <returns></returns>
public static Expression<Func<T1, bool>> Not<T1>(this Expression<Func<T1, bool>> exp, bool condition = true) => (Expression<Func<T1, bool>>)InternalNotExpression(condition, exp);
#endregion
#region T1, T2
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, bool>> And<T1, T2>(this Expression<Func<T1, T2, bool>> exp1, Expression<Func<T1, T2, bool>> exp2) => And(exp1, true, exp2);
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, bool>> And<T1, T2>(this Expression<Func<T1, T2, bool>> exp1, bool condition, Expression<Func<T1, T2, bool>> exp2) => (Expression<Func<T1, T2, bool>>)InternalAndOrExpression(condition, exp1, exp2, true);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, bool>> Or<T1, T2>(this Expression<Func<T1, T2, bool>> exp1, Expression<Func<T1, T2, bool>> exp2) => Or(exp1, true, exp2);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, bool>> Or<T1, T2>(this Expression<Func<T1, T2, bool>> exp1, bool condition, Expression<Func<T1, T2, bool>> exp2) => (Expression<Func<T1, T2, bool>>)InternalAndOrExpression(condition, exp1, exp2, false);
/// <summary>
/// 将 lambda 表达式取反
/// </summary>
/// <param name="exp"></param>
/// <param name="condition">true 时生效</param>
/// <returns></returns>
public static Expression<Func<T1, T2, bool>> Not<T1, T2>(this Expression<Func<T1, T2, bool>> exp, bool condition = true) => (Expression<Func<T1, T2, bool>>)InternalNotExpression(condition, exp);
#endregion
#region T1, T2, T3
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, bool>> And<T1, T2, T3>(this Expression<Func<T1, T2, T3, bool>> exp1, Expression<Func<T1, T2, T3, bool>> exp2) => And(exp1, true, exp2);
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, bool>> And<T1, T2, T3>(this Expression<Func<T1, T2, T3, bool>> exp1, bool condition, Expression<Func<T1, T2, T3, bool>> exp2) => (Expression<Func<T1, T2, T3, bool>>)InternalAndOrExpression(condition, exp1, exp2, true);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, bool>> Or<T1, T2, T3>(this Expression<Func<T1, T2, T3, bool>> exp1, Expression<Func<T1, T2, T3, bool>> exp2) => Or(exp1, true, exp2);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, bool>> Or<T1, T2, T3>(this Expression<Func<T1, T2, T3, bool>> exp1, bool condition, Expression<Func<T1, T2, T3, bool>> exp2) => (Expression<Func<T1, T2, T3, bool>>)InternalAndOrExpression(condition, exp1, exp2, false);
/// <summary>
/// 将 lambda 表达式取反
/// </summary>
/// <param name="exp"></param>
/// <param name="condition">true 时生效</param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, bool>> Not<T1, T2, T3>(this Expression<Func<T1, T2, T3, bool>> exp, bool condition = true) => (Expression<Func<T1, T2, T3, bool>>)InternalNotExpression(condition, exp);
#endregion
#region T1, T2, T3, T4
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, bool>> And<T1, T2, T3, T4>(this Expression<Func<T1, T2, T3, T4, bool>> exp1, Expression<Func<T1, T2, T3, T4, bool>> exp2) => And(exp1, true, exp2);
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, bool>> And<T1, T2, T3, T4>(this Expression<Func<T1, T2, T3, T4, bool>> exp1, bool condition, Expression<Func<T1, T2, T3, T4, bool>> exp2) => (Expression<Func<T1, T2, T3, T4, bool>>)InternalAndOrExpression(condition, exp1, exp2, true);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, bool>> Or<T1, T2, T3, T4>(this Expression<Func<T1, T2, T3, T4, bool>> exp1, Expression<Func<T1, T2, T3, T4, bool>> exp2) => Or(exp1, true, exp2);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, bool>> Or<T1, T2, T3, T4>(this Expression<Func<T1, T2, T3, T4, bool>> exp1, bool condition, Expression<Func<T1, T2, T3, T4, bool>> exp2) => (Expression<Func<T1, T2, T3, T4, bool>>)InternalAndOrExpression(condition, exp1, exp2, false);
/// <summary>
/// 将 lambda 表达式取反
/// </summary>
/// <param name="exp"></param>
/// <param name="condition">true 时生效</param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, bool>> Not<T1, T2, T3, T4>(this Expression<Func<T1, T2, T3, T4, bool>> exp, bool condition = true) => (Expression<Func<T1, T2, T3, T4, bool>>)InternalNotExpression(condition, exp);
#endregion
#region T1, T2, T3, T4, T5
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, T5, bool>> And<T1, T2, T3, T4, T5>(this Expression<Func<T1, T2, T3, T4, T5, bool>> exp1, Expression<Func<T1, T2, T3, T4, T5, bool>> exp2) => And(exp1, true, exp2);
/// <summary>
/// 使用 and 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, T5, bool>> And<T1, T2, T3, T4, T5>(this Expression<Func<T1, T2, T3, T4, T5, bool>> exp1, bool condition, Expression<Func<T1, T2, T3, T4, T5, bool>> exp2) => (Expression<Func<T1, T2, T3, T4, T5, bool>>)InternalAndOrExpression(condition, exp1, exp2, true);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, T5, bool>> Or<T1, T2, T3, T4, T5>(this Expression<Func<T1, T2, T3, T4, T5, bool>> exp1, Expression<Func<T1, T2, T3, T4, T5, bool>> exp2) => Or(exp1, true, exp2);
/// <summary>
/// 使用 or 拼接两个 lambda 表达式
/// </summary>
/// <param name="exp1"></param>
/// <param name="condition">true 时生效</param>
/// <param name="exp2"></param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, T5, bool>> Or<T1, T2, T3, T4, T5>(this Expression<Func<T1, T2, T3, T4, T5, bool>> exp1, bool condition, Expression<Func<T1, T2, T3, T4, T5, bool>> exp2) => (Expression<Func<T1, T2, T3, T4, T5, bool>>)InternalAndOrExpression(condition, exp1, exp2, false);
/// <summary>
/// 将 lambda 表达式取反
/// </summary>
/// <param name="exp"></param>
/// <param name="condition">true 时生效</param>
/// <returns></returns>
public static Expression<Func<T1, T2, T3, T4, T5, bool>> Not<T1, T2, T3, T4, T5>(this Expression<Func<T1, T2, T3, T4, T5, bool>> exp, bool condition = true) => (Expression<Func<T1, T2, T3, T4, T5, bool>>)InternalNotExpression(condition, exp);
#endregion
public static bool IsParameter(this Expression exp)
{
var test = new TestParameterExpressionVisitor();
test.Visit(exp);
return test.Result;
}
public static ParameterExpression GetParameter(this Expression exp)
{
var test = new GetParameterExpressionVisitor();
test.Visit(exp);
return test.Result;
}
static ConcurrentDictionary<Type, ConcurrentDictionary<string, MethodInfo>> _dicTypeMethod = new ConcurrentDictionary<Type, ConcurrentDictionary<string, MethodInfo>>();
public static bool IsStringJoin(this MethodCallExpression exp, out Expression tolistObjectExpOut, out MethodInfo toListMethodOut, out LambdaExpression toListArgs0Out)
{
if (exp.Arguments.Count == 2 &&
exp.Arguments[1].NodeType == ExpressionType.Call &&
exp.Arguments[1].Type.FullName.StartsWith("System.Collections.Generic.List`1") &&
exp.Arguments[1] is MethodCallExpression toListMethod &&
toListMethod.Method.Name == "ToList" &&
toListMethod.Arguments.Count == 1 &&
toListMethod.Arguments[0] is UnaryExpression joinExpArgs1Args0Tmp &&
joinExpArgs1Args0Tmp.Operand is LambdaExpression toListArgs0)
{
tolistObjectExpOut = toListMethod.Object;
toListMethodOut = toListMethod.Type.GetGenericArguments().FirstOrDefault() == typeof(string) ?
toListMethod.Method :
toListMethod.Method.GetGenericMethodDefinition().MakeGenericMethod(typeof(string));
toListArgs0Out = toListArgs0;
return true;
}
tolistObjectExpOut = null;
toListMethodOut = null;
toListArgs0Out = null;
return false;
}
public static object GetConstExprValue(this Expression exp)
{
if (exp.IsParameter()) return null;
var expStack = new Stack<Expression>();
var exp2 = exp;
while (true)
{
switch (exp2?.NodeType)
{
case ExpressionType.Constant:
expStack.Push(exp2);
break;
case ExpressionType.MemberAccess:
expStack.Push(exp2);
exp2 = (exp2 as MemberExpression).Expression;
if (exp2 == null) break;
continue;
case ExpressionType.Call:
return Expression.Lambda(exp).Compile().DynamicInvoke();
case ExpressionType.TypeAs:
case ExpressionType.Convert:
var oper2 = (exp2 as UnaryExpression).Operand;
if (oper2.NodeType == ExpressionType.Parameter)
{
var oper2Parm = oper2 as ParameterExpression;
expStack.Push(exp2.Type.IsAbstract || exp2.Type.IsInterface ? oper2Parm : Expression.Parameter(exp2.Type, oper2Parm.Name));
}
else
expStack.Push(oper2);
break;
}
break;
}
object firstValue = null;
switch (expStack.First().NodeType)
{
case ExpressionType.Constant:
var expStackFirst = expStack.Pop() as ConstantExpression;
firstValue = expStackFirst?.Value;
break;
case ExpressionType.MemberAccess:
var expStackFirstMem = expStack.First() as MemberExpression;
if (expStackFirstMem.Expression?.NodeType == ExpressionType.Constant)
firstValue = (expStackFirstMem.Expression as ConstantExpression)?.Value;
else
return Expression.Lambda(exp).Compile().DynamicInvoke();
break;
}
while (expStack.Any())
{
var expStackItem = expStack.Pop();
switch (expStackItem.NodeType)
{
case ExpressionType.MemberAccess:
var memExp = expStackItem as MemberExpression;
if (memExp.Member.MemberType == MemberTypes.Property)
firstValue = ((PropertyInfo)memExp.Member).GetValue(firstValue, null);
else if (memExp.Member.MemberType == MemberTypes.Field)
firstValue = ((FieldInfo)memExp.Member).GetValue(firstValue);
break;
}
}
return firstValue;
}
}
internal class NewExpressionVisitor : ExpressionVisitor
{
ParameterExpression[] _newParameters;
ParameterExpression[] _oldParameters;
public NewExpressionVisitor(ParameterExpression newParam, ParameterExpression oldParam) : this(new[] { newParam }, new[] { oldParam }) { }
public NewExpressionVisitor(ParameterExpression[] newParams, ParameterExpression[] oldParams)
{
this._newParameters = newParams;
this._oldParameters = oldParams;
}
public Expression Replace(Expression exp) => this.Visit(exp);
protected override Expression VisitParameter(ParameterExpression node)
{
for (var a = 0; a < _oldParameters.Length; a++)
if (_oldParameters[a] == node)
return _newParameters[a];
return node;
}
}
internal class TestParameterExpressionVisitor : ExpressionVisitor
{
public bool Result { get; private set; }
protected override Expression VisitParameter(ParameterExpression node)
{
if (!Result) Result = true;
return node;
}
}
internal class GetParameterExpressionVisitor : ExpressionVisitor
{
public ParameterExpression Result { get; private set; }
protected override Expression VisitParameter(ParameterExpression node)
{
if (Result == null) Result = node;
return node;
}
}
}