lambda转化为sql语句(完整版)
今天整理文档，发现了很久之前写的代码，把完整版的拿出来。估计也没几个人需要了。mysql版本的
using MySql.Data.MySqlClient; using System; using System.Collections; using System.Collections.Generic; using System.Data; using System.Data.SqlClient; using System.Linq; using System.Linq.Expressions; using System.Reflection; using System.Text; using System.Threading.Tasks; using Yl.CM.Server.Common.Enum; namespace Yl.CM.Server.Common { public class UserId { public string Id { get; set; } public string Pws { get; set; } public int? LoginCount { get; set; } } public static class LambdaToSqlHelper { #region 实现方法 public static int GetPageByDataTable(this DataTable dt, int size) { int totalCount = dt.Rows[0][0].ToString().ToIntByStr(); return totalCount; //% size > 0 ? totalCount / size + 1 : totalCount / size; } #region DataTable转化成List public static List<T> ConvertToModelList<T>(DataTable dt) where T : new() { List<T> ts = new List<T>();// 定义集合 Type type = typeof(T); // 获得此模型的类型 string tempName = ""; foreach (DataRow dr in dt.Rows) { T t = new T(); PropertyInfo[] propertys = t.GetType().GetProperties();// 获得此模型的公共属性 foreach (PropertyInfo pi in propertys) { tempName = pi.Name; if (dt.Columns.Contains(tempName)) { if (!pi.CanWrite) { continue; } if (pi.PropertyType.Name == "Boolean") { bool value = false; if (dr[tempName].ToString() == "1") { value = true; } pi.SetValue(t, value, null); } else { object value = dr[tempName]; if (value != DBNull.Value) { pi.SetValue(t, value, null); } } } } ts.Add(t); } return ts; } #endregion DataTable转化成List #region List转换成DataTable public static DataTable ConvertToDataTable<T>(IEnumerable<T> collection) { DataTable dtReturn = new DataTable(); PropertyInfo[] oProps = null; foreach (T rec in collection) { if (oProps == null) { oProps = ((Type)rec.GetType()).GetProperties(); foreach (PropertyInfo pi in oProps) { Type colType = pi.PropertyType; if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>))) { colType = colType.GetGenericArguments()[0]; } dtReturn.Columns.Add(new DataColumn(pi.Name, colType)); } } DataRow dr = dtReturn.NewRow(); foreach (PropertyInfo pi in oProps) { dr[pi.Name] = pi.GetValue(rec, null) == null ? DBNull.Value : pi.GetValue(rec, null); } dtReturn.Rows.Add(dr); } return (dtReturn); //var props = typeof(T).GetProperties(); //var dt = new DataTable(); //dt.Columns.AddRange(props.Select(p => new DataColumn(p.Name,p.PropertyType)).ToArray()); //if (collection.Count() > 0) //{ // for (int i = 0; i < collection.Count(); i++) // { // ArrayList tempList = new ArrayList(); // foreach (PropertyInfo pi in props) // { // object obj = pi.GetValue(collection.ElementAt(i), null); // tempList.Add(obj); // } // object[] array = tempList.ToArray(); // dt.LoadDataRow(array, true); // } //} //return dt; } #endregion List转换成DataTable #region 获取 插入语句 public static string GetInsertSqlByT<T>(T t) where T : class { var type = typeof(T); var typeAttrList = type.GetProperties(); string sb = "INSERT INTO `{0}` ({1}) values ({2})"; StringBuilder sbName = new StringBuilder(""); StringBuilder sbValue = new StringBuilder(""); foreach (var ta in typeAttrList) { sbName.Append("`"); sbName.Append(ta.Name); sbName.Append("`"); sbName.Append(","); sbValue.Append("`"); sbValue.Append(GetValueStringByType(ta.GetValue(t, null))); sbValue.Append("`"); sbValue.Append(","); } string name = sbName.ToString().Substring(0, sbName.Length - 1); string value = sbValue.ToString().Substring(0, sbValue.Length - 1); return string.Format(sb, type.Name.ToLower(), name, value); } public static string GetInsertSqlByT<T>(T t, out MySqlParameter[] pars) where T : class { var type = typeof(T); var typeAttrList = type.GetProperties(); string sb = "INSERT INTO `{0}` ({1}) values ({2})"; StringBuilder sbName = new StringBuilder(""); StringBuilder sbValue = new StringBuilder(""); int markPar = 0; pars = new MySqlParameter[typeAttrList.Length - 1]; foreach (var ta in typeAttrList) { if (ta.Name.ToLower() == "id") { continue; } sbName.Append("`"); sbName.Append(ta.Name); sbName.Append("`"); sbName.Append(","); sbValue.Append(""); sbValue.Append("@par" + markPar); sbValue.Append(""); sbValue.Append(","); MySqlParameter p = new MySqlParameter(); p.ParameterName = "@par" + markPar; p.Value = ta.GetValue(t, null); // p.SqlDbType =SqlTypeString2SqlType(ta.PropertyType.Name.ToLower()); pars[markPar] = p; markPar++; } string name = sbName.ToString().Substring(0, sbName.Length - 1); string value = sbValue.ToString().Substring(0, sbValue.Length - 1); return string.Format(sb, type.Name.ToLower(), name, value); } public static string GetInsertSqlToIDByT<T>(T t, out MySqlParameter[] pars) where T : class { var type = typeof(T); var typeAttrList = type.GetProperties(); string sb = "INSERT INTO `{0}` ({1}) values ({2})"; StringBuilder sbName = new StringBuilder(""); StringBuilder sbValue = new StringBuilder(""); int markPar = 0; pars = new MySqlParameter[typeAttrList.Length]; foreach (var ta in typeAttrList) { sbName.Append("`"); sbName.Append(ta.Name); sbName.Append("`"); sbName.Append(","); sbValue.Append(""); sbValue.Append("@par" + markPar); sbValue.Append(""); sbValue.Append(","); MySqlParameter p = new MySqlParameter(); p.ParameterName = "@par" + markPar; p.Value = ta.GetValue(t, null); // p.SqlDbType =SqlTypeString2SqlType(ta.PropertyType.Name.ToLower()); pars[markPar] = p; markPar++; } string name = sbName.ToString().Substring(0, sbName.Length - 1); string value = sbValue.ToString().Substring(0, sbValue.Length - 1); return string.Format(sb, type.Name.ToLower(), name, value); } #endregion 获取 插入语句 #region 获取修改语句 public static string GetUpdateSqlByT<T>(T t, Expression<Func<T, bool>> func, out MySqlParameter[] pars) where T : class { var type = typeof(T); var typeAttrList = type.GetProperties(); string sb = "UPDATE " + type.Name.ToLower() + " SET {0} where 1=1 and {1}"; StringBuilder sbValue = new StringBuilder(""); int markPar = 0; List<ParMODEL> listPar = new List<ParMODEL>(); string where = GetWhereSql(func, listPar); pars = new MySqlParameter[typeAttrList.Length + listPar.Count - 1]; foreach (var ta in typeAttrList) { if (ta.Name == "ID") { continue; } sbValue.Append("`"); sbValue.Append(ta.Name); sbValue.Append("`"); sbValue.Append("="); sbValue.Append(""); sbValue.Append("@parValue" + markPar); sbValue.Append(""); sbValue.Append(","); MySqlParameter p = new MySqlParameter(); p.ParameterName = "@parValue" + markPar; p.Value = ta.GetValue(t, null); pars[markPar] = p; markPar++; } string value = sbValue.ToString().Substring(0, sbValue.Length - 1); foreach (var l in listPar) { MySqlParameter p = new MySqlParameter(); p.ParameterName = l.name; p.Value = l.value; pars[markPar] = p; markPar++; } return string.Format(sb, value, where); } #endregion 获取修改语句 #region 获取分页语句 public static string GetSelectSqlByPage<T>(int pageIndex, int pageSize, Expression<Func<T, bool>> where, out MySqlParameter[] parameter) where T : class { List<ParMODEL> parModelList = new List<ParMODEL>(); string sqlWhere = LambdaToSqlHelper.GetWhereSql<T>(where, parModelList); parameter = LambdaToSqlHelper.GetParmetersByList(parModelList); string sqlTable = LambdaToSqlHelper.GetSelectTableSqlPage<T>(); string sqlPageTotal = LambdaToSqlHelper.GetTotalPage(pageIndex, pageSize); StringBuilder sb = new StringBuilder(""); sb.Append(sqlTable); sb.Append(" and "); sb.Append(sqlWhere); sb.Append(" "); sb.Append(sqlPageTotal); return sb.ToString(); } public static string GetSelectSqlByPage<T>(int pageIndex, int pageSize, Expression<Func<T, bool>> where, Expression<Func<T, object>> order, out MySqlParameter[] parameter) where T : class { List<ParMODEL> parModelList = new List<ParMODEL>(); string sqlWhere = LambdaToSqlHelper.GetWhereSql<T>(where, parModelList); parameter = LambdaToSqlHelper.GetParmetersByList(parModelList); string sqlOrder = LambdaToSqlHelper.GetOrderSql<T>(order); string sqlTable = LambdaToSqlHelper.GetSelectTableSqlPage<T>(); string sqlPageTotal = LambdaToSqlHelper.GetTotalPage(pageIndex, pageSize); StringBuilder sb = new StringBuilder(""); sb.Append(sqlTable); sb.Append(" and "); sb.Append(sqlWhere); sb.Append(" "); sb.Append(sqlOrder); sb.Append(sqlPageTotal); return sb.ToString(); } public static string GetSelectSql<T>(Expression<Func<T, bool>> where, Expression<Func<T, object>> order, out MySqlParameter[] parameter) where T : class { List<ParMODEL> parModelList = new List<ParMODEL>(); string sqlWhere = LambdaToSqlHelper.GetWhereSql<T>(where, parModelList); parameter = LambdaToSqlHelper.GetParmetersByList(parModelList); string sqlOrder = LambdaToSqlHelper.GetOrderSql<T>(order); string sqlTable = LambdaToSqlHelper.GetSelectTableSql<T>(); StringBuilder sb = new StringBuilder(""); sb.Append(sqlTable); sb.Append(" and "); sb.Append(sqlWhere); sb.Append(" "); sb.Append(sqlOrder); return sb.ToString(); } public static string GetSelectSql<T>(Expression<Func<T, bool>> where, out MySqlParameter[] pars) where T : class { List<ParMODEL> parModelList = new List<ParMODEL>(); string sqlWhere = LambdaToSqlHelper.GetWhereSql<T>(where, parModelList); pars = LambdaToSqlHelper.GetParmetersByList(parModelList); string sqlTable = LambdaToSqlHelper.GetSelectTableSql<T>(); StringBuilder sb = new StringBuilder(""); sb.Append(sqlTable); sb.Append(" and "); sb.Append(sqlWhere); sb.Append(" "); return sb.ToString(); } public static string GetSelectSql<T>() where T : class { List<ParMODEL> parModelList = new List<ParMODEL>(); string sqlTable = LambdaToSqlHelper.GetSelectTableSql<T>(); StringBuilder sb = new StringBuilder(""); sb.Append(sqlTable); sb.Append(" "); return sb.ToString(); } #endregion 获取分页语句 #region 获取删除语句 public static string GetDeleteSqlByID<T>(List<int> list, out MySqlParameter[] pars) where T : class { var typeT = typeof(T); StringBuilder sb = new StringBuilder(); pars = new MySqlParameter[list.Count]; for (int i = 0; i < list.Count; i++) { sb.Append("@par" + i + ","); MySqlParameter p = new MySqlParameter(); p.ParameterName = "@par" + i; p.Value = list[i]; // p.SqlDbType =SqlTypeString2SqlType(ta.PropertyType.Name.ToLower()); pars[i] = p; } string value = sb.ToString().Substring(0, sb.Length - 1); return "update `" + typeT.Name.ToLower() + "` set isdelete=" + (int)CommonEnum.IsDelete.已删除 + " where id in(" + value + ") "; } public static string GetDeleteSqlByID<T>(int id, out MySqlParameter[] pars) where T : class { var typeT = typeof(T); StringBuilder sb = new StringBuilder(); pars = new MySqlParameter[1]; sb.Append("@par" + id + ","); MySqlParameter p = new MySqlParameter(); p.ParameterName = "@par" + id; p.Value = id; // p.SqlDbType =SqlTypeString2SqlType(ta.PropertyType.Name.ToLower()); pars[0] = p; string value = sb.ToString().Substring(0, sb.Length - 1); return "update `" + typeT.Name.ToLower() + "` set isdelete=" + (int)CommonEnum.IsDelete.已删除 + " where id in(" + value + ") "; } public static string GetDeleteSqlByIDsTrue<T>(List<int> list, out MySqlParameter[] pars) where T : class { var typeT = typeof(T); StringBuilder sb = new StringBuilder(); pars = new MySqlParameter[list.Count]; for (int i = 0; i < list.Count; i++) { sb.Append("@par" + i + ","); MySqlParameter p = new MySqlParameter(); p.ParameterName = "@par" + i; p.Value = list[i]; // p.SqlDbType =SqlTypeString2SqlType(ta.PropertyType.Name.ToLower()); pars[i] = p; } string value = sb.ToString().Substring(0, sb.Length - 1); return "delete from `" + typeT.Name.ToLower() + "` where id in(" + value + ") "; } public static string DeleteEntityByWhereTrue<T>(Expression<Func<T, bool>> func, out MySqlParameter[] pars) where T : class { var typeT = typeof(T); List<ParMODEL> list = new List<ParMODEL>(); string sql = "delete from `" + typeT.Name.ToLower() + "` where 1=1 and " + GetWhereSql<T>(func, list); pars = new MySqlParameter[list.Count]; int markPar = 0; foreach (var l in list) { MySqlParameter p = new MySqlParameter(); p.ParameterName = l.name; p.Value = l.value; pars[markPar] = p; markPar++; } return sql; } #endregion 获取删除语句 #region 获取数量语句 public static string GetSelectSqlCount<T>(Expression<Func<T, bool>> where, out MySqlParameter[] parameter) where T : class { List<ParMODEL> parModelList = new List<ParMODEL>(); string sqlWhere = LambdaToSqlHelper.GetWhereSql<T>(where, parModelList); parameter = LambdaToSqlHelper.GetParmetersByList(parModelList); string sqlTable = LambdaToSqlHelper.GetSelectTableSqlCount<T>(); StringBuilder sb = new StringBuilder(""); sb.Append(sqlTable); sb.Append(" and "); sb.Append(sqlWhere); sb.Append(" "); return sb.ToString(); } #endregion 获取数量语句 #endregion 实现方法 #region 基础方法 #region 获取条件语句方法 private static string GetWhereSql<T>(Expression<Func<T, bool>> func, List<ParMODEL> parModelList) where T : class { string res = ""; if (func.Body is BinaryExpression) { //起始参数 BinaryExpression be = ((BinaryExpression)func.Body); res = BinarExpressionProvider(be.Left, be.Right, be.NodeType, parModelList); } else if (func.Body is MethodCallExpression) { MethodCallExpression be = ((MethodCallExpression)func.Body); res = ExpressionRouter(func.Body, parModelList); } else { res = " "; } return res; } #endregion 获取条件语句方法 #region 将引用类型传出注入参数转化为所需参数 private static MySqlParameter[] GetParmetersByList(List<ParMODEL> parModelList) { MySqlParameter[] parameter = new MySqlParameter[parModelList.Count]; for (int i = 0; i < parModelList.Count; i++) { MySqlParameter par = new MySqlParameter(); par.ParameterName = "@" + parModelList[i].name; par.Value = parModelList[i].value; parameter[i] = par; } return parameter; } #endregion 将引用类型传出注入参数转化为所需参数 #region 获取排序语句 order by private static string GetOrderSql<T>(Expression<Func<T, object>> exp) where T : class { var res = ""; if (exp.Body is UnaryExpression) { UnaryExpression ue = ((UnaryExpression)exp.Body); List<ParMODEL> parModelList = new List<ParMODEL>(); res = "order by `" + ExpressionRouter(ue.Operand, parModelList).ToLower() + "`"; } else { MemberExpression order = ((MemberExpression)exp.Body); res = "order by `" + order.Member.Name.ToLower() + "`"; } return res; } #endregion 获取排序语句 order by #region 获取select表名的 sql 语句 private static string GetSelectTableSqlCount<T>() where T : class { var typeT = typeof(T); return string.Format("select count(*) from `{0}` where 1=1 ", typeT.Name.ToLower()); } private static string GetSelectTableSql<T>() where T : class { var typeT = typeof(T); var attrNameList = typeT.GetProperties().Select(a => a.Name).ToList(); StringBuilder sb = new StringBuilder(); foreach (var name in attrNameList) { sb.Append("`"); sb.Append(name); sb.Append("`"); sb.Append(","); } string cos = sb.ToString().Substring(0, sb.Length - 1); return string.Format("select {0} from `{1}` where 1=1 ", cos, typeT.Name.ToLower()); } private static string GetSelectTableSqlPage<T>() where T : class { var typeT = typeof(T); var attrNameList = typeT.GetProperties().Select(a => a.Name).ToList(); StringBuilder sb = new StringBuilder(); foreach (var name in attrNameList) { sb.Append("`"); sb.Append(name); sb.Append("`"); sb.Append(","); } string cos = sb.ToString().Substring(0, sb.Length - 1); return string.Format("select SQL_CALC_FOUND_ROWS {0} from `{1}` where 1=1 ", cos, typeT.Name.ToLower()); } #endregion 获取select表名的 sql 语句 #region 获取分页的后尾句 private static string GetTotalPage(int pageIndex, int pageSize) { return " limit " + pageSize * (pageIndex - 1) + "," + pageSize + " ;SELECT FOUND_ROWS() as TotalCount"; } #endregion 获取分页的后尾句 #region 获取添加返回标识列语句 public static string GetSqlIDEntity() { return "SELECT @@IDENTITY AS ID"; } #endregion 获取添加返回标识列语句 #endregion 基础方法 #region 底层 public static bool In<T>(this T obj, T[] array) { return true; } public static bool NotIn<T>(this T obj, T[] array) { return true; } public static bool Like(this string str, string likeStr) { return true; } public static bool NotLike(this string str, string likeStr) { return true; } private static string GetValueStringByType(object oj) { if (oj == null) { return "null"; } else if (oj is ValueType) { return oj.ToString(); } else if (oj is string || oj is DateTime || oj is char) { return string.Format("'{0}'", oj.ToString()); } else { return string.Format("'{0}'", oj.ToString()); } } private static string BinarExpressionProvider(Expression left, Expression right, ExpressionType type, List<ParMODEL> parModelList) { string sb = "("; //先处理左边 string reLeftStr = ExpressionRouter(left, parModelList); sb += reLeftStr; sb += ExpressionTypeCast(type); //再处理右边 string tmpStr = ExpressionRouter(right, parModelList); if (tmpStr == "null") { if (sb.EndsWith(" =")) { sb = sb.Substring(0, sb.Length - 2) + " is null"; } else if (sb.EndsWith("<>")) { sb = sb.Substring(0, sb.Length - 2) + " is not null"; } } else { //添加参数 sb += tmpStr; } return sb += ")"; } private static string ExpressionRouter(Expression exp, List<ParMODEL> parModelList) { string sb = string.Empty; if (exp is BinaryExpression) { BinaryExpression be = ((BinaryExpression)exp); return BinarExpressionProvider(be.Left, be.Right, be.NodeType, parModelList); } else if (exp is MemberExpression) { MemberExpression me = ((MemberExpression)exp); if (!exp.ToString().StartsWith("value")) { return me.Member.Name; } else { var result = Expression.Lambda(exp).Compile().DynamicInvoke(); if (result == null) { return "null"; } else if (result is ValueType) { ParMODEL p = new ParMODEL(); p.name = "par" + (parModelList.Count + 1); p.value = result.ToString().ToIntByStr(); parModelList.Add(p); //return ce.Value.ToString(); return "@par" + parModelList.Count; } else if (result is string || result is DateTime || result is char) { ParMODEL p = new ParMODEL(); p.name = "par" + (parModelList.Count + 1); p.value = result.ToString(); parModelList.Add(p); //return string.Format("'{0}'", ce.Value.ToString()); return "@par" + parModelList.Count; } else if (result is int[]) { var rl = result as int[]; StringBuilder sbIntStr = new StringBuilder(); foreach (var r in rl) { ParMODEL p = new ParMODEL(); p.name = "par" + (parModelList.Count + 1); p.value = r.ToString().ToIntByStr(); parModelList.Add(p); //return string.Format("'{0}'", ce.Value.ToString()); sbIntStr.Append("@par" + parModelList.Count + ","); } return sbIntStr.ToString().Substring(0, sbIntStr.ToString().Length - 1); } else if (result is string[]) { var rl = result as string[]; StringBuilder sbIntStr = new StringBuilder(); foreach (var r in rl) { ParMODEL p = new ParMODEL(); p.name = "par" + (parModelList.Count + 1); p.value = r.ToString(); parModelList.Add(p); //return string.Format("'{0}'", ce.Value.ToString()); sbIntStr.Append("@par" + parModelList.Count + ","); } return sbIntStr.ToString().Substring(0, sbIntStr.ToString().Length - 1); } } } else if (exp is NewArrayExpression) { NewArrayExpression ae = ((NewArrayExpression)exp); StringBuilder tmpstr = new StringBuilder(); foreach (Expression ex in ae.Expressions) { tmpstr.Append(ExpressionRouter(ex, parModelList)); tmpstr.Append(","); } //添加参数 return tmpstr.ToString(0, tmpstr.Length - 1); } else if (exp is MethodCallExpression) { MethodCallExpression mce = (MethodCallExpression)exp; string par = ExpressionRouter(mce.Arguments[0], parModelList); if (mce.Method.Name == "Like") { //添加参数用 return string.Format("({0} like {1})", par, ExpressionRouter(mce.Arguments[1], parModelList)); } else if (mce.Method.Name == "NotLike") { //添加参数用 return string.Format("({0} Not like {1})", par, ExpressionRouter(mce.Arguments[1], parModelList)); } else if (mce.Method.Name == "In") { //添加参数用 return string.Format("{0} In ({1})", par, ExpressionRouter(mce.Arguments[1], parModelList)); } else if (mce.Method.Name == "NotIn") { //添加参数用 return string.Format("{0} Not In ({1})", par, ExpressionRouter(mce.Arguments[1], parModelList)); } } else if (exp is ConstantExpression) { ConstantExpression ce = ((ConstantExpression)exp); if (ce.Value == null) { return "null"; } else if (ce.Value is ValueType) { ParMODEL p = new ParMODEL(); p.name = "par" + (parModelList.Count + 1); p.value = ce.Value.ToString().ToIntByStr(); parModelList.Add(p); //return ce.Value.ToString(); return "@par" + parModelList.Count; } else if (ce.Value is string || ce.Value is DateTime || ce.Value is char) { ParMODEL p = new ParMODEL(); p.name = "par" + (parModelList.Count + 1); p.value = ce.Value.ToString(); parModelList.Add(p); //return string.Format("'{0}'", ce.Value.ToString()); return "@par" + parModelList.Count; } //对数值进行参数附加 } else if (exp is UnaryExpression) { UnaryExpression ue = ((UnaryExpression)exp); return ExpressionRouter(ue.Operand, parModelList); } return null; } private static string ExpressionTypeCast(ExpressionType type) { switch (type) { case ExpressionType.And: case ExpressionType.AndAlso: return " AND "; case ExpressionType.Equal: return " ="; case ExpressionType.GreaterThan: return " >"; case ExpressionType.GreaterThanOrEqual: return ">="; case ExpressionType.LessThan: return "<"; case ExpressionType.LessThanOrEqual: return "<="; case ExpressionType.NotEqual: return "<>"; case ExpressionType.Or: case ExpressionType.OrElse: return " Or "; case ExpressionType.Add: case ExpressionType.AddChecked: return "+"; case ExpressionType.Subtract: case ExpressionType.SubtractChecked: return "-"; case ExpressionType.Divide: return "/"; case ExpressionType.Multiply: case ExpressionType.MultiplyChecked: return "*"; default: return null; } } #endregion 底层 } #region 表达式累加 不支持ef 慎用，把问题复杂化了 public static class PredicateBuilder { public static Expression<Func<T, bool>> True<T>() { return f => true; } public static Expression<Func<T, bool>> False<T>() { return f => false; } public static Expression<T> Compose<T>(this Expression<T> first, Expression<T> second, Func<Expression, Expression, Expression> merge) { // build parameter map (from parameters of second to parameters of first) var map = first.Parameters.Select((f, i) => new { f, s = second.Parameters[i] }).ToDictionary(p => p.s, p => p.f); // replace parameters in the second lambda expression with parameters from the first var secondBody = ParameterRebinder.ReplaceParameters(map, second.Body); // apply composition of lambda expression bodies to parameters from the first expression return Expression.Lambda<T>(merge(first.Body, secondBody), first.Parameters); } public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> first, Expression<Func<T, bool>> second) { return first.Compose(second, Expression.And); } public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> first, Expression<Func<T, bool>> second) { return first.Compose(second, Expression.Or); } } public class ParameterRebinder : ExpressionVisitor { private readonly Dictionary<ParameterExpression, ParameterExpression> map; public ParameterRebinder(Dictionary<ParameterExpression, ParameterExpression> map) { this.map = map ?? new Dictionary<ParameterExpression, ParameterExpression>(); } public static Expression ReplaceParameters(Dictionary<ParameterExpression, ParameterExpression> map, Expression exp) { return new ParameterRebinder(map).Visit(exp); } protected override Expression VisitParameter(ParameterExpression p) { ParameterExpression replacement; if (map.TryGetValue(p, out replacement)) { p = replacement; } return base.VisitParameter(p); } } #endregion 表达式累加 不支持ef 慎用，把问题复杂化了 public class SqlParMODEL { public string sql { set; get; } private List<ParMODEL> parList { set; get; } } public class ParMODEL { public string name { set; get; } public object value { set; get; } } }
