You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
103 lines
2.9 KiB
103 lines
2.9 KiB
using System;
|
|
using System.Collections.Generic;
|
|
using System.Linq.Expressions;
|
|
|
|
namespace EC.Utils
|
|
{
|
|
/// <summary>
|
|
/// 动态Lamada
|
|
/// 版 本：V3.0.0
|
|
/// 版 权：EasyCode
|
|
/// 作 者：LXC
|
|
/// </summary>
|
|
public partial class ExtLinq<T> where T : new()
|
|
{
|
|
private List<Expression> m_lstExpression = null;
|
|
private ParameterExpression m_Parameter = null;
|
|
|
|
public ExtLinq()
|
|
{
|
|
m_lstExpression = new List<Expression>();
|
|
m_Parameter = Expression.Parameter(typeof(T), "x");
|
|
}
|
|
|
|
public void CreateExpression(string strPropertyName, object strValue, SearchMethod expressType)
|
|
{
|
|
Expression expRes = null;
|
|
MemberExpression member = Expression.PropertyOrField(m_Parameter, strPropertyName);
|
|
if (expressType == SearchMethod.Contains)
|
|
{
|
|
expRes = Expression.Call(member, typeof(string).GetMethod("Contains"), Expression.Constant(strValue));
|
|
}
|
|
else if (expressType == SearchMethod.Equal)
|
|
{
|
|
expRes = Expression.Equal(member, Expression.Constant(strValue, member.Type));
|
|
}
|
|
else if (expressType == SearchMethod.NotEqual)
|
|
{
|
|
expRes = Expression.NotEqual(member, Expression.Constant(strValue, member.Type));
|
|
}
|
|
else if (expressType == SearchMethod.LessThan)
|
|
{
|
|
expRes = Expression.LessThan(member, Expression.Constant(strValue, member.Type));
|
|
}
|
|
else if (expressType == SearchMethod.LessThanOrEqual)
|
|
{
|
|
expRes = Expression.LessThanOrEqual(member, Expression.Constant(strValue, member.Type));
|
|
}
|
|
else if (expressType == SearchMethod.GreaterThan)
|
|
{
|
|
expRes = Expression.GreaterThan(member, Expression.Constant(strValue, member.Type));
|
|
}
|
|
else if (expressType == SearchMethod.GreaterThanOrEqual)
|
|
{
|
|
expRes = Expression.GreaterThanOrEqual(member, Expression.Constant(strValue, member.Type));
|
|
}
|
|
m_lstExpression.Add(expRes);
|
|
}
|
|
|
|
public void CreateExpression(string strPropertyName, List<object> lstValue)
|
|
{
|
|
Expression expRes = null;
|
|
MemberExpression member = Expression.PropertyOrField(m_Parameter, strPropertyName);
|
|
foreach (var oValue in lstValue)
|
|
{
|
|
if (expRes == null)
|
|
{
|
|
expRes = Expression.Equal(member, Expression.Constant(oValue, member.Type));
|
|
}
|
|
else
|
|
{
|
|
expRes = Expression.Or(expRes, Expression.Equal(member, Expression.Constant(oValue, member.Type)));
|
|
}
|
|
}
|
|
m_lstExpression.Add(expRes);
|
|
}
|
|
|
|
public Expression<Func<T, bool>> GetLambda()
|
|
{
|
|
Expression whereExpr = null;
|
|
foreach (var expr in this.m_lstExpression)
|
|
{
|
|
if (whereExpr == null)
|
|
whereExpr = expr;
|
|
else
|
|
whereExpr = Expression.And(whereExpr, expr);
|
|
}
|
|
if (whereExpr == null)
|
|
return null;
|
|
return Expression.Lambda<Func<T, bool>>(whereExpr, m_Parameter);
|
|
}
|
|
}
|
|
|
|
public enum SearchMethod
|
|
{
|
|
Contains, //like
|
|
Equal, //等于
|
|
NotEqual, //不等于
|
|
LessThan, //小于
|
|
LessThanOrEqual, //小于等于
|
|
GreaterThan, //大于
|
|
GreaterThanOrEqual //大于等于
|
|
}
|
|
}
|