DynamicLinq.cs
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// ***********************************************************************
// <copyright file="DynamicLinq.cs" company="">
// Copyright (c) . All rights reserved.
// </copyright>
// <summary>动态linq</summary>
// ***********************************************************************
using Hh.Mes.Common.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
namespace Hh.Mes.Common.Infrastructure
{
public static class DynamicLinq
{
public static ParameterExpression CreateLambdaParam<T>(string name)
{
return Expression.Parameter(typeof(T), name);
}
/// <summary>
/// 创建linq表达示的body部分
/// </summary>
public static Expression GenerateBody<T>(this ParameterExpression param, Filter filterObj)
{
PropertyInfo property = typeof(T).GetProperty(filterObj.Key);
//组装左边
Expression left = Expression.Property(param, property);
//组装右边
Expression right = null;
if (
(property.PropertyType == typeof(int) || property.PropertyType == typeof(int?))
|| (property.PropertyType == typeof(short) || property.PropertyType == typeof(short?))
|| (property.PropertyType == typeof(long) || property.PropertyType == typeof(long?))
|| (property.PropertyType == typeof(decimal) || property.PropertyType == typeof(decimal?))
|| (property.PropertyType == typeof(double) || property.PropertyType == typeof(double?))
)
{
string stype = property.PropertyType.ToString().ToLower();
Expression leftexp = property.PropertyType.ToString().IndexOf("Nullable") >= 0 ? Expression.Property(left, "Value") : left;
object filterValue = null;
if (string.IsNullOrEmpty(filterObj.Value))
{
filterValue = 0;
}
else
{
if (property.PropertyType == typeof(int) || property.PropertyType == typeof(int?))
{ filterValue = int.Parse(filterObj.Value); }
else if (property.PropertyType == typeof(short) || property.PropertyType == typeof(short?))
{ filterValue = short.Parse(filterObj.Value); }
else if (property.PropertyType == typeof(long) || property.PropertyType == typeof(long?))
{ filterValue = long.Parse(filterObj.Value); }
else if (property.PropertyType == typeof(decimal) || property.PropertyType == typeof(decimal?))
{ filterValue = decimal.Parse(filterObj.Value); }
else if (property.PropertyType == typeof(double) || property.PropertyType == typeof(double?))
{ filterValue = double.Parse(filterObj.Value); }
//if (stype.IndexOf("int") >= 0)
//{ filterValue = int.Parse(filterObj.Value); }
//else if (stype.IndexOf("short") >= 0)
//{ filterValue = short.Parse(filterObj.Value); }
//else if (stype.IndexOf("long") >= 0)
//{ filterValue = long.Parse(filterObj.Value); }
//else if (stype.IndexOf("decimal") >= 0)
//{ filterValue = decimal.Parse(filterObj.Value); }
//else if (stype.IndexOf("double") >= 0)
//{ filterValue = double.Parse(filterObj.Value); }
}
Type type = filterValue.GetType();
left = Expression.Call(leftexp, type.GetMethod("CompareTo", new Type[] { type }),
Expression.Constant(filterValue));
right = Expression.Constant(0);
}
else if (property.PropertyType == typeof(DateTime) || property.PropertyType == typeof(DateTime?))
{
if (filterObj.Contrast == "like")
{
Expression leftexp = property.PropertyType == typeof(DateTime) ? left : Expression.Property(left, "Value");
filterObj.Contrast = "==";
if (filterObj.Value.Length == 4)
{
left = Expression.Call(Expression.Property(leftexp, "Year"), typeof(int).GetMethod("Equals", new Type[] { typeof(int) }),
Expression.Constant(int.Parse(filterObj.Value)));
}
else if (filterObj.Value.Length == 7)
{
DateTime date = Convert.ToDateTime(filterObj.Value);
left = Expression.Call(Expression.Property(leftexp, "Year"), typeof(int).GetMethod("Equals", new Type[] { typeof(int) }),
Expression.Constant(date.Year)).And(Expression.Call(Expression.Property(leftexp, "Month"), typeof(int).GetMethod("Equals", new Type[] { typeof(int) }),
Expression.Constant(date.Month)));
}
else
{
DateTime date = Convert.ToDateTime(filterObj.Value);
left = Expression.Call(Expression.Property(leftexp, "Year"), typeof(int).GetMethod("Equals", new Type[] { typeof(int) }),
Expression.Constant(date.Year)).And(Expression.Call(Expression.Property(leftexp, "Month"), typeof(int).GetMethod("Equals", new Type[] { typeof(int) }),
Expression.Constant(date.Month))).And(Expression.Call(Expression.Property(leftexp, "Day"), typeof(int).GetMethod("Equals", new Type[] { typeof(int) }),
Expression.Constant(date.Day)));
}
right = Expression.Constant(true);
}
else
{
Expression leftexp = property.PropertyType == typeof(DateTime) ? left : Expression.Property(left, "Value");
object filterValue = string.IsNullOrEmpty(filterObj.Value) ? DateTime.Now : DateTime.Parse(filterObj.Value);
left = Expression.Call(leftexp, typeof(DateTime).GetMethod("CompareTo", new Type[] { typeof(DateTime) }),
Expression.Constant(filterValue));
right = Expression.Constant(0);
}
}
else if (property.PropertyType == typeof(string))
{
filterObj.Value = filterObj.Value.ToUpper();
left = Expression.Call(left, typeof(string).GetMethod("ToUpper", new Type[] { }));
right = Expression.Constant((filterObj.Value));
}
else if (property.PropertyType == typeof(bool) || property.PropertyType == typeof(bool?))
{
if (!string.IsNullOrEmpty(filterObj.Value))
{
if (filterObj.Value.ToLower().Equals("true") || filterObj.Value.ToLower().Equals("1"))
{
filterObj.Value = "true";
}
else
{
filterObj.Value = "false";
}
}
Expression leftexp = property.PropertyType == typeof(bool) ? left : Expression.Property(left, "Value");
object filterValue = string.IsNullOrEmpty(filterObj.Value) ? bool.Parse("true") : bool.Parse(filterObj.Value);
left = Expression.Call(leftexp, typeof(bool).GetMethod("CompareTo", new Type[] { typeof(bool) }),
Expression.Constant(filterValue));
right = Expression.Constant(0);
}
else if (property.PropertyType == typeof(Guid) || property.PropertyType == typeof(Guid?))
{
Expression leftexp = property.PropertyType == typeof(Guid) ? left : Expression.Property(left, "Value");
object filterValue = string.IsNullOrEmpty(filterObj.Value) ? Guid.Parse("00000000-0000-0000-0000-000000000000") : Guid.Parse(filterObj.Value);
left = Expression.Call(leftexp, typeof(Guid).GetMethod("CompareTo", new Type[] { typeof(Guid) }),
Expression.Constant(filterValue));
right = Expression.Constant(0);
}
else
{
throw new Exception("暂不能解析该Key的类型");
}
CheckFilterString(filterObj.JqContrast, property.PropertyType);
//c.XXX=="XXX"
Expression filter = Expression.Equal(left, right);//等于
switch (filterObj.Contrast)
{
case "<="://小于等于
filter = Expression.LessThanOrEqual(left, right);
break;
case "<"://小于
filter = Expression.LessThan(left, right);
break;
case ">"://大于
filter = Expression.GreaterThan(left, right);
break;
case ">="://大于等于
filter = Expression.GreaterThanOrEqual(left, right);
break;
case "!="://不等于
filter = Expression.NotEqual(left, right);
break;
case "like"://包含
filter = Expression.Call(left, typeof(string).GetMethod("Contains", new Type[] { typeof(string) }),
Expression.Constant(filterObj.Value));
break;
case "not like"://不包含
filter = Expression.Not(Expression.Call(left, typeof(string).GetMethod("Contains", new Type[] { typeof(string) }),
Expression.Constant(filterObj.Value)));
break;
case "in"://属于
var lExp = Expression.Constant(filterObj.Value.Split(',').ToList()); //数组
var methodInfo = typeof(List<string>).GetMethod("Contains", new Type[] { typeof(string) }); //Contains语句
filter = Expression.Call(lExp, methodInfo, left);
break;
case "not in"://不属于
var listExpression = Expression.Constant(filterObj.Value.Split(',').ToList()); //数组
var method = typeof(List<string>).GetMethod("Contains", new Type[] { typeof(string) }); //Contains语句
filter = Expression.Not(Expression.Call(listExpression, method, left));
break;
case "begin with"://开始于
filter = Expression.Call(left, typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) }),
Expression.Constant(filterObj.Value));
break;
case "not begin with"://不开始于
filter = Expression.Not(Expression.Call(left, typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) }),
Expression.Constant(filterObj.Value)));
break;
case "end with"://结束于
filter = Expression.Call(left, typeof(string).GetMethod("EndsWith", new Type[] { typeof(string) }),
Expression.Constant(filterObj.Value));
break;
case "not end with"://不结束于
filter = Expression.Not(Expression.Call(left, typeof(string).GetMethod("EndsWith", new Type[] { typeof(string) }),
Expression.Constant(filterObj.Value)));
break;
case "null"://为空
filter = Expression.Equal(left, Expression.Constant(string.Empty));
break;
case "not null"://不为空
filter = Expression.NotEqual(left, Expression.Constant(string.Empty));
break;
}
return filter;
}
private static void CheckFilterString(string p, Type type)
{
bool valid = false;
string errmsg = string.Format("{0}类型不支持{1}操作", type, p);
string typeS = type.ToString();
if (type == typeof(int) || type == typeof(int?) || type == typeof(decimal) || type == typeof(decimal?) || type == typeof(long) || type == typeof(long?) || type == typeof(short) || type == typeof(short?) || type == typeof(double) || type == typeof(double?) || type == typeof(DateTime) || type == typeof(DateTime?))
{
if (type == typeof(DateTime) || type == typeof(DateTime?))
{
valid = ("eq,ne,lt,le,gt,ge,cn".Split(',').Contains(p));
}
else
{
valid = ("eq,ne,lt,le,gt,ge".Split(',').Contains(p));
}
}
else if (type == typeof(string))
{
valid = ("eq,ne,bw,bn,in,ni,ew,en,cn,nc,nu,nn".Split(',').Contains(p));
}
else if (type == typeof(Guid) || type == typeof(Guid?) || type == typeof(bool) || type == typeof(bool?))
{
valid = ("eq,ne".Split(',').Contains(p));
}
if (!valid) { throw new Exception(errmsg); };
}
public static Expression<Func<T, bool>> GenerateTypeBody<T>(this ParameterExpression param, Filter filterObj)
{
return (Expression<Func<T, bool>>)(param.GenerateBody<T>(filterObj));
}
/// <summary>
/// 创建完整的lambda
/// </summary>
public static LambdaExpression GenerateLambda(this ParameterExpression param, Expression body)
{
//c=>c.XXX=="XXX"
return Expression.Lambda(body, param);
}
public static Expression<Func<T, bool>> GenerateTypeLambda<T>(this ParameterExpression param, Expression body)
{
return (Expression<Func<T, bool>>)(param.GenerateLambda(body));
}
public static Expression AndAlso(this Expression expression, Expression expressionRight)
{
return Expression.AndAlso(expression, expressionRight);
}
public static Expression Or(this Expression expression, Expression expressionRight)
{
return Expression.Or(expression, expressionRight);
}
public static Expression And(this Expression expression, Expression expressionRight)
{
return Expression.And(expression, expressionRight);
}
//系统已经有该函数的实现
//public static IQueryable<T> Where<T>(this IQueryable<T> query, Expression expression)
//{
// Expression expr = Expression.Call(typeof(Queryable), "Where", new[] { typeof(T) },
// Expression.Constant(query), expression);
// //生成动态查询
// IQueryable<T> result = query.Provider.CreateQuery<T>(expr);
// return result;
//}
public static IQueryable<T> GenerateFilter<T>(this IQueryable<T> query, string filterjson)
{
if (!string.IsNullOrEmpty(filterjson) && filterjson != "null")
{
var filters = JsonHelper.Instance.Deserialize<IEnumerable<Filter>>(filterjson);
var param = CreateLambdaParam<T>("c");
Expression result = Expression.Constant(true);
foreach (var filter in filters)
{
result = result.AndAlso(param.GenerateBody<T>(filter));
}
query = query.Where(param.GenerateTypeLambda<T>(result));
}
return query;
}
public static Expression<Func<T, bool>> AndAlso<T>(this Expression<Func<T, bool>> expr1, Expression<Func<T, bool>> expr2)
{
var parameter = Expression.Parameter(typeof(T));
var leftVisitor = new ReplaceExpressionVisitor(expr1.Parameters[0], parameter);
var left = leftVisitor.Visit(expr1.Body);
var rightVisitor = new ReplaceExpressionVisitor(expr2.Parameters[0], parameter);
var right = rightVisitor.Visit(expr2.Body);
return Expression.Lambda<Func<T, bool>>(
Expression.AndAlso(left, right), parameter);
}
private class ReplaceExpressionVisitor : ExpressionVisitor
{
private readonly Expression _oldValue;
private readonly Expression _newValue;
public ReplaceExpressionVisitor(Expression oldValue, Expression newValue)
{
_oldValue = oldValue;
_newValue = newValue;
}
public override Expression Visit(Expression node)
{
if (node == _oldValue)
return _newValue;
return base.Visit(node);
}
}
}
}