lamber表达式sql_lambda表达式转换sql
usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Linq;usingSystem.Linq.Expressions;usingSystem.Text;usingSystem.Threading.Tasks;namespaceMaiCore
{///
///
///
public classLambdaToSqlHelper
{///
///NodeType枚舉///
private enumEnumNodeType
{///
///二元運算符///
[Description("二元運算符")]
BinaryOperator= 1,///
///一元運算符///
[Description("一元運算符")]
UndryOperator= 2,///
///常量表達式///
[Description("常量表達式")]
Constant= 3,///
///成員(變量)///
[Description("成員(變量)")]
MemberAccess= 4,///
///函數///
[Description("函數")]
Call= 5,///
///未知///
[Description("未知")]
Unknown= -99,///
///不支持///
[Description("不支持")]
NotSupported= -98}///
///判斷表達式類型///
/// lambda表達式
///
private staticEnumNodeType CheckExpressionType(Expression exp)
{switch(exp.NodeType)
{caseExpressionType.AndAlso:caseExpressionType.OrElse:caseExpressionType.Equal:caseExpressionType.GreaterThanOrEqual:caseExpressionType.LessThanOrEqual:caseExpressionType.GreaterThan:caseExpressionType.LessThan:caseExpressionType.NotEqual:returnEnumNodeType.BinaryOperator;caseExpressionType.Constant:returnEnumNodeType.Constant;caseExpressionType.MemberAccess:returnEnumNodeType.MemberAccess;caseExpressionType.Call:returnEnumNodeType.Call;caseExpressionType.Not:caseExpressionType.Convert:returnEnumNodeType.UndryOperator;default:returnEnumNodeType.Unknown;
}
}///
///表達式類型轉換///
///
///
private static stringExpressionTypeCast(ExpressionType type)
{switch(type)
{caseExpressionType.And:caseExpressionType.AndAlso:return "and";caseExpressionType.Equal:return "=";caseExpressionType.GreaterThan:return ">";caseExpressionType.GreaterThanOrEqual:return ">=";caseExpressionType.LessThan:return "";caseExpressionType.Or:caseExpressionType.OrElse:return "or";caseExpressionType.Add:caseExpressionType.AddChecked:return "+";caseExpressionType.Subtract:caseExpressionType.SubtractChecked:return "-";caseExpressionType.Divide:return "/";caseExpressionType.Multiply:caseExpressionType.MultiplyChecked:return "*";default:return null;
}
}private static string BinarExpressionProvider(Expression exp, ListlistSqlParaModel)
{
BinaryExpression be= exp asBinaryExpression;
Expression left=be.Left;
Expression right=be.Right;
ExpressionType type=be.NodeType;string sb = "(";//先處理左邊
sb +=ExpressionRouter(left, listSqlParaModel);
sb+=ExpressionTypeCast(type);//再處理右邊
string sbTmp =ExpressionRouter(right, listSqlParaModel);if (sbTmp == "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";
}elsesb+=sbTmp;return sb += ")";
}private static string ConstantExpressionProvider(Expression exp, ListlistSqlParaModel)
{
ConstantExpression ce= exp asConstantExpression;if (ce.Value == null)
{return "null";
}else if (ce.Value isValueType)
{
GetSqlParaModel(listSqlParaModel, GetValueType(ce.Value));return "@para" +listSqlParaModel.Count;
}else if (ce.Value is string || ce.Value is DateTime || ce.Value is char)
{
GetSqlParaModel(listSqlParaModel, GetValueType(ce.Value));return "@para" +listSqlParaModel.Count;
}return "";
}private static string LambdaExpressionProvider(Expression exp, ListlistSqlParaModel)
{
LambdaExpression le= exp asLambdaExpression;returnExpressionRouter(le.Body, listSqlParaModel);
}private static string MemberExpressionProvider(Expression exp, ListlistSqlParaModel)
{if (!exp.ToString().StartsWith("value"))
{
MemberExpression me= exp asMemberExpression;if (me.Member.Name == "Now")
{
GetSqlParaModel(listSqlParaModel, DateTime.Now);return "@para" +listSqlParaModel.Count;
}returnme.Member.Name;
}else{var result =Expression.Lambda(exp).Compile().DynamicInvoke();if (result == null)
{return "null";
}else if (result isValueType)
{
GetSqlParaModel(listSqlParaModel, GetValueType(result));return "@para" +listSqlParaModel.Count;
}else if (result is string || result is DateTime || result is char)
{
GetSqlParaModel(listSqlParaModel, GetValueType(result));return "@para" +listSqlParaModel.Count;
}else if (result is int[])
{var rl = result as int[];
StringBuilder sbTmp= newStringBuilder();foreach (var r inrl)
{
GetSqlParaModel(listSqlParaModel, r.ToString().ToInt32());
sbTmp.Append("@para" + listSqlParaModel.Count + ",");
}return sbTmp.ToString().Substring(0, sbTmp.ToString().Length - 1);
}else if (result is string[])
{var rl = result as string[];
StringBuilder sbTmp= newStringBuilder();foreach (var r inrl)
{
GetSqlParaModel(listSqlParaModel, r.ToString());
sbTmp.Append("@para" + listSqlParaModel.Count + ",");
}return sbTmp.ToString().Substring(0, sbTmp.ToString().Length - 1);
}
}return "";
}private static string MethodCallExpressionProvider(Expression exp, ListlistSqlParaModel)
{
MethodCallExpression mce= exp asMethodCallExpression;if (mce.Method.Name == "Contains")
{if (mce.Object == null)
{return string.Format("{0} in ({1})", ExpressionRouter(mce.Arguments[1], listSqlParaModel), ExpressionRouter(mce.Arguments[0], listSqlParaModel));
}else{if (mce.Object.NodeType ==ExpressionType.MemberAccess)
{//w => w.name.Contains("1")
var _name =ExpressionRouter(mce.Object, listSqlParaModel);var _value = ExpressionRouter(mce.Arguments[0], listSqlParaModel);var index = _value.RetainNumber().ToInt32() - 1;
listSqlParaModel[index].value= "%{0}%".FormatWith(listSqlParaModel[index].value);return string.Format("{0} like {1}", _name, _value);
}
}
}else if (mce.Method.Name == "OrderBy")
{return string.Format("{0} asc", ExpressionRouter(mce.Arguments[1], listSqlParaModel));
}else if (mce.Method.Name == "OrderByDescending")
{return string.Format("{0} desc", ExpressionRouter(mce.Arguments[1], listSqlParaModel));
}else if (mce.Method.Name == "ThenBy")
{return string.Format("{0},{1} asc", MethodCallExpressionProvider(mce.Arguments[0], listSqlParaModel), ExpressionRouter(mce.Arguments[1], listSqlParaModel));
}else if (mce.Method.Name == "ThenByDescending")
{return string.Format("{0},{1} desc", MethodCallExpressionProvider(mce.Arguments[0], listSqlParaModel), ExpressionRouter(mce.Arguments[1], listSqlParaModel));
}else if (mce.Method.Name == "Like")
{return string.Format("({0} like {1})", ExpressionRouter(mce.Arguments[0], listSqlParaModel), ExpressionRouter(mce.Arguments[1], listSqlParaModel).Replace("'", ""));
}else if (mce.Method.Name == "NotLike")
{return string.Format("({0} not like '%{1}%')", ExpressionRouter(mce.Arguments[0], listSqlParaModel), ExpressionRouter(mce.Arguments[1], listSqlParaModel).Replace("'", ""));
}else if (mce.Method.Name == "In")
{return string.Format("{0} in ({1})", ExpressionRouter(mce.Arguments[0], listSqlParaModel), ExpressionRouter(mce.Arguments[1], listSqlParaModel));
}else if (mce.Method.Name == "NotIn")
{return string.Format("{0} not in ({1})", ExpressionRouter(mce.Arguments[0], listSqlParaModel), ExpressionRouter(mce.Arguments[1], listSqlParaModel));
}return "";
}private static string NewArrayExpressionProvider(Expression exp, ListlistSqlParaModel)
{
NewArrayExpression ae= exp asNewArrayExpression;
StringBuilder sbTmp= newStringBuilder();foreach (Expression ex inae.Expressions)
{
sbTmp.Append(ExpressionRouter(ex, listSqlParaModel));
sbTmp.Append(",");
}return sbTmp.ToString(0, sbTmp.Length - 1);
}private static string ParameterExpressionProvider(Expression exp, ListlistSqlParaModel)
{
ParameterExpression pe= exp asParameterExpression;returnpe.Type.Name;
}private static string UnaryExpressionProvider(Expression exp, ListlistSqlParaModel)
{
UnaryExpression ue= exp asUnaryExpression;var result =ExpressionRouter(ue.Operand, listSqlParaModel);
ExpressionType type=exp.NodeType;if (type ==ExpressionType.Not)
{if (result.Contains("in"))
{
result= result.Replace("in", "not in");
}if (result.Contains("like"))
{
result= result.Replace("like", "not like");
}
}returnresult;
}///
///路由計算///
///
///
///
private static string ExpressionRouter(Expression exp, ListlistSqlParaModel)
{var nodeType =exp.NodeType;if (exp is BinaryExpression) //表示具有二進制運算符的表達式
{returnBinarExpressionProvider(exp, listSqlParaModel);
}else if (exp is ConstantExpression) //表示具有常數值的表達式
{returnConstantExpressionProvider(exp, listSqlParaModel);
}else if (exp is LambdaExpression) //介紹 lambda 表達式。 它捕獲一個類似于 .NET 方法主體的代碼塊
{returnLambdaExpressionProvider(exp, listSqlParaModel);
}else if (exp is MemberExpression) //表示訪問字段或屬性
{returnMemberExpressionProvider(exp, listSqlParaModel);
}else if (exp is MethodCallExpression) //表示對靜態方法或實例方法的調用
{returnMethodCallExpressionProvider(exp, listSqlParaModel);
}else if (exp is NewArrayExpression) //表示創建一個新數組，并可能初始化該新數組的元素
{returnNewArrayExpressionProvider(exp, listSqlParaModel);
}else if (exp is ParameterExpression) //表示一個命名的參數表達式。
{returnParameterExpressionProvider(exp, listSqlParaModel);
}else if (exp is UnaryExpression) //表示具有一元運算符的表達式
{returnUnaryExpressionProvider(exp, listSqlParaModel);
}return null;
}///
///值類型轉換///
///
///
private static object GetValueType(object_value)
{var _type =_value.GetType().Name;switch(_type)
{case "Decimal": return_value.ToDecimal();case "Int32": return_value.ToInt32();case "DateTime": return_value.ToDateTime();case "String": return_value.ToString();case "Char":return_value.ToChar();case "Boolean":return_value.ToBoolean();default: return_value;
}
}///
///sql參數///
///
///
private static void GetSqlParaModel(List listSqlParaModel, objectval)
{
SqlParaModel p= newSqlParaModel();
p.name= "para" + (listSqlParaModel.Count + 1);
p.value=val;
listSqlParaModel.Add(p);
}///
///lambda表達式轉換sql///
///
///
///
///
public static string GetWhereSql(Expression> where, List listSqlParaModel) where T : class{string result = string.Empty;if (where != null)
{
Expression exp= where.Body asExpression;
result=ExpressionRouter(exp, listSqlParaModel);
}if (result != string.Empty)
{
result= "where" +result;
}returnresult;
}///
///lambda表達式轉換sql///
///
///
///
public static string GetOrderBySql(Expression, IOrderedQueryable>> orderBy) where T : class{string result = string.Empty;if (orderBy != null && orderBy.Body isMethodCallExpression)
{
MethodCallExpression exp= orderBy.Body asMethodCallExpression;
List listSqlParaModel = new List();
result=MethodCallExpressionProvider(exp, listSqlParaModel);
}if (result != string.Empty)
{
result= "order by" +result;
}returnresult;
}///
///lambda表達式轉換sql///
///
///
///
public static string GetQueryField(Expression>fields)
{
StringBuilder sbSelectFields= newStringBuilder();if (fields.Body isNewExpression)
{
NewExpression ne= fields.Body asNewExpression;for (var i = 0; i < ne.Members.Count; i++)
{
sbSelectFields.Append(ne.Members[i].Name+ ",");
}
}else if (fields.Body isParameterExpression)
{
sbSelectFields.Append("*");
}else{
sbSelectFields.Append("*");
}if (sbSelectFields.Length > 1)
{
sbSelectFields= sbSelectFields.Remove(sbSelectFields.Length - 1, 1);
}returnsbSelectFields.ToString();
}
}
}-----------------------------------------------------------------------------------------------demo：classProgram
{static void Main(string[] args)
{//Expression> where = w => w.id == "123456";
Expression> where = w => w.id.Contains("1");
List listSqlParaModel = new List();var sql = LambdaToSqlHelper.GetWhereSql(where, listSqlParaModel);
}
}classMyClass
{public stringid;public stringname;public stringdesc;public decimalprice;public intstock;public boolisShow;publicDateTime createTime;
}
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