DMSLinq表达式框架实现(二)

DMSExpressionVisitor类重写,其实这个类就是System.Linq下面的ExpressionVisitor类,改它也是因为更好控制我们的SQL语句而已.
下面贴出代码:
View Code
  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Linq.Expressions;
  6 using System.Collections.ObjectModel;
  7 
  8 namespace KingNET.DMSFrame.DMSLinq
  9 {
 10     public abstract class DMSExpressionVisitor
 11     {
 12         protected virtual Expression Visit(Expression exp)
 13         {
 14             if (exp == null)
 15             {
 16                 return exp;
 17             }
 18             switch (exp.NodeType)
 19             {
 20                 case ExpressionType.Add:
 21                 case ExpressionType.AddChecked:
 22                 case ExpressionType.And:
 23                 case ExpressionType.AndAlso:
 24                 case ExpressionType.ArrayIndex:
 25                 case ExpressionType.Coalesce:
 26                 case ExpressionType.Divide:
 27                 case ExpressionType.Equal:
 28                 case ExpressionType.ExclusiveOr:
 29                 case ExpressionType.GreaterThan:
 30                 case ExpressionType.GreaterThanOrEqual:
 31                 case ExpressionType.LeftShift:
 32                 case ExpressionType.LessThan:
 33                 case ExpressionType.LessThanOrEqual:
 34                 case ExpressionType.Modulo:
 35                 case ExpressionType.Multiply:
 36                 case ExpressionType.MultiplyChecked:
 37                 case ExpressionType.NotEqual:
 38                 case ExpressionType.Or:
 39                 case ExpressionType.OrElse:
 40                 case ExpressionType.RightShift:
 41                 case ExpressionType.Subtract:
 42                 case ExpressionType.SubtractChecked:
 43                     return this.VisitBinary((BinaryExpression)exp);
 44 
 45                 case ExpressionType.ArrayLength:
 46                 case ExpressionType.Convert:
 47                 case ExpressionType.ConvertChecked:
 48                 case ExpressionType.Negate:
 49                 case ExpressionType.NegateChecked:
 50                 case ExpressionType.Not:
 51                 case ExpressionType.Quote:
 52                 case ExpressionType.TypeAs:
 53                     return this.VisitUnary((UnaryExpression)exp);
 54 
 55                 case ExpressionType.Call:
 56                     return this.VisitMethodCall((MethodCallExpression)exp);
 57 
 58                 case ExpressionType.Conditional:
 59                     return this.VisitConditional((ConditionalExpression)exp);
 60 
 61                 case ExpressionType.Constant:
 62                     return this.VisitConstant((ConstantExpression)exp);
 63 
 64                 case ExpressionType.Invoke:
 65                     return this.VisitInvocation((InvocationExpression)exp);
 66 
 67                 case ExpressionType.Lambda:
 68                     return this.VisitLambda((LambdaExpression)exp);
 69 
 70                 case ExpressionType.ListInit:
 71                     return this.VisitListInit((ListInitExpression)exp);
 72 
 73                 case ExpressionType.MemberAccess:
 74                     return this.VisitMemberAccess((MemberExpression)exp);
 75 
 76                 case ExpressionType.MemberInit:
 77                     return this.VisitMemberInit((MemberInitExpression)exp);
 78 
 79                 case ExpressionType.New:
 80                     return this.VisitNew((NewExpression)exp);
 81 
 82                 case ExpressionType.NewArrayInit:
 83                 case ExpressionType.NewArrayBounds:
 84                     return this.VisitNewArray((NewArrayExpression)exp);
 85 
 86                 case ExpressionType.Parameter:
 87                     return this.VisitParameter((ParameterExpression)exp);
 88 
 89                 case ExpressionType.TypeIs:
 90                     return this.VisitTypeIs((TypeBinaryExpression)exp);
 91 
 92             }
 93             throw new Exception(string.Format("Unhandled expression type: '{0}'", exp.NodeType));
 94         }
 95         protected virtual MemberBinding VisitBinding(MemberBinding binding)
 96         {
 97             switch (binding.BindingType)
 98             {
 99                 case MemberBindingType.Assignment:
100                     return this.VisitMemberAssignment((MemberAssignment)binding);
101 
102                 case MemberBindingType.MemberBinding:
103                     return this.VisitMemberMemberBinding((MemberMemberBinding)binding);
104 
105                 case MemberBindingType.ListBinding:
106                     return this.VisitMemberListBinding((MemberListBinding)binding);
107 
108                 default:
109                     throw new Exception(string.Format("Unhandled binding type '{0}'", binding.BindingType));
110             }
111         }
112         protected virtual ElementInit VisitElementInitializer(ElementInit initializer)
113         {
114             ReadOnlyCollection<Expression> readOnlyCollection = this.VisitExpressionList(initializer.Arguments);
115             if (readOnlyCollection != initializer.Arguments)
116             {
117                 return Expression.ElementInit(initializer.AddMethod, readOnlyCollection);
118             }
119             return initializer;
120         }
121         protected virtual Expression VisitUnary(UnaryExpression u)
122         {
123             Expression expression = this.Visit(u.Operand);
124             if (expression != u.Operand)
125             {
126                 return Expression.MakeUnary(u.NodeType, expression, u.Type, u.Method);
127             }
128             return u;
129         }
130         protected virtual Expression VisitBinary(BinaryExpression b)
131         {
132             Expression expression = this.Visit(b.Left);
133             Expression expression2 = this.Visit(b.Right);
134             Expression expression3 = this.Visit(b.Conversion);
135             if (expression == b.Left && expression2 == b.Right && expression3 == b.Conversion)
136             {
137                 return b;
138             }
139             if (b.NodeType == ExpressionType.Coalesce && b.Conversion != null)
140             {
141                 return Expression.Coalesce(expression, expression2, expression3 as LambdaExpression);
142             }
143             return Expression.MakeBinary(b.NodeType, expression, expression2, b.IsLiftedToNull, b.Method);
144         }
145         protected virtual Expression VisitTypeIs(TypeBinaryExpression b)
146         {
147             Expression expression = this.Visit(b.Expression);
148             if (expression != b.Expression)
149             {
150                 return Expression.TypeIs(expression, b.TypeOperand);
151             }
152             return b;
153         }
154         protected virtual Expression VisitConstant(ConstantExpression c)
155         {
156             return c;
157         }
158         protected virtual Expression VisitConditional(ConditionalExpression c)
159         {
160             Expression expression = this.Visit(c.Test);
161             Expression expression2 = this.Visit(c.IfTrue);
162             Expression expression3 = this.Visit(c.IfFalse);
163             if (expression != c.Test || expression2 != c.IfTrue || expression3 != c.IfFalse)
164             {
165                 return Expression.Condition(expression, expression2, expression3);
166             }
167             return c;
168         }
169         protected virtual Expression VisitParameter(ParameterExpression p)
170         {
171             return p;
172         }
173         protected virtual Expression VisitMemberAccess(MemberExpression m)
174         {
175             Expression expression = this.Visit(m.Expression);
176             if (expression != m.Expression)
177             {
178                 return Expression.MakeMemberAccess(expression, m.Member);
179             }
180             return m;
181         }
182         protected virtual Expression VisitMethodCall(MethodCallExpression m)
183         {
184             Expression expression = this.Visit(m.Object);
185             IEnumerable<Expression> enumerable = this.VisitExpressionList(m.Arguments);
186             if (expression != m.Object || enumerable != m.Arguments)
187             {
188                 return Expression.Call(expression, m.Method, enumerable);
189             }
190             return m;
191         }
192         protected virtual ReadOnlyCollection<Expression> VisitExpressionList(ReadOnlyCollection<Expression> original)
193         {
194             List<Expression> list = null;
195             int i = 0;
196             int count = original.Count;
197             while (i < count)
198             {
199                 Expression expression = this.Visit(original[i]);
200                 if (list != null)
201                 {
202                     list.Add(expression);
203                 }
204                 else
205                 {
206                     if (expression != original[i])
207                     {
208                         list = new List<Expression>(count);
209                         for (int j = 0; j < i; j++)
210                         {
211                             list.Add(original[j]);
212                         }
213                         list.Add(expression);
214                     }
215                 }
216                 i++;
217             }
218             if (list != null)
219             {
220                 return list.AsReadOnly();
221             }
222             return original;
223         }
224         protected virtual MemberAssignment VisitMemberAssignment(MemberAssignment assignment)
225         {
226             Expression expression = this.Visit(assignment.Expression);
227             if (expression != assignment.Expression)
228             {
229                 return Expression.Bind(assignment.Member, expression);
230             }
231             return assignment;
232         }
233         protected virtual MemberMemberBinding VisitMemberMemberBinding(MemberMemberBinding binding)
234         {
235             IEnumerable<MemberBinding> enumerable = this.VisitBindingList(binding.Bindings);
236             if (enumerable != binding.Bindings)
237             {
238                 return Expression.MemberBind(binding.Member, enumerable);
239             }
240             return binding;
241         }
242         protected virtual MemberListBinding VisitMemberListBinding(MemberListBinding binding)
243         {
244             IEnumerable<ElementInit> enumerable = this.VisitElementInitializerList(binding.Initializers);
245             if (enumerable != binding.Initializers)
246             {
247                 return Expression.ListBind(binding.Member, enumerable);
248             }
249             return binding;
250         }
251         protected virtual IEnumerable<MemberBinding> VisitBindingList(ReadOnlyCollection<MemberBinding> original)
252         {
253             List<MemberBinding> list = null;
254             int i = 0;
255             int count = original.Count;
256             while (i < count)
257             {
258                 MemberBinding memberBinding = this.VisitBinding(original[i]);
259                 if (list != null)
260                 {
261                     list.Add(memberBinding);
262                 }
263                 else
264                 {
265                     if (memberBinding != original[i])
266                     {
267                         list = new List<MemberBinding>(count);
268                         for (int j = 0; j < i; j++)
269                         {
270                             list.Add(original[j]);
271                         }
272                         list.Add(memberBinding);
273                     }
274                 }
275                 i++;
276             }
277             if (list != null)
278             {
279                 return list;
280             }
281             return original;
282         }
283         protected virtual IEnumerable<ElementInit> VisitElementInitializerList(ReadOnlyCollection<ElementInit> original)
284         {
285             List<ElementInit> list = null;
286             int i = 0;
287             int count = original.Count;
288             while (i < count)
289             {
290                 ElementInit elementInit = this.VisitElementInitializer(original[i]);
291                 if (list != null)
292                 {
293                     list.Add(elementInit);
294                 }
295                 else
296                 {
297                     if (elementInit != original[i])
298                     {
299                         list = new List<ElementInit>(count);
300                         for (int j = 0; j < i; j++)
301                         {
302                             list.Add(original[j]);
303                         }
304                         list.Add(elementInit);
305                     }
306                 }
307                 i++;
308             }
309             if (list != null)
310             {
311                 return list;
312             }
313             return original;
314         }
315         protected virtual Expression VisitLambda(LambdaExpression lambda)
316         {
317             Expression expression = this.Visit(lambda.Body);
318             if (expression != lambda.Body)
319             {
320                 return Expression.Lambda(lambda.Type, expression, lambda.Parameters);
321             }
322             return lambda;
323         }
324         protected virtual NewExpression VisitNew(NewExpression nex)
325         {
326             IEnumerable<Expression> enumerable = this.VisitExpressionList(nex.Arguments);
327             if (enumerable == nex.Arguments)
328             {
329                 return nex;
330             }
331             if (nex.Members != null)
332             {
333                 return Expression.New(nex.Constructor, enumerable, nex.Members);
334             }
335             return Expression.New(nex.Constructor, enumerable);
336         }
337         protected virtual Expression VisitMemberInit(MemberInitExpression init)
338         {
339             NewExpression newExpression = this.VisitNew(init.NewExpression);
340             IEnumerable<MemberBinding> enumerable = this.VisitBindingList(init.Bindings);
341             if (newExpression != init.NewExpression || enumerable != init.Bindings)
342             {
343                 return Expression.MemberInit(newExpression, enumerable);
344             }
345             return init;
346         }
347         protected virtual Expression VisitListInit(ListInitExpression init)
348         {
349             NewExpression newExpression = this.VisitNew(init.NewExpression);
350             IEnumerable<ElementInit> enumerable = this.VisitElementInitializerList(init.Initializers);
351             if (newExpression != init.NewExpression || enumerable != init.Initializers)
352             {
353                 return Expression.ListInit(newExpression, enumerable);
354             }
355             return init;
356         }
357         protected virtual Expression VisitNewArray(NewArrayExpression na)
358         {
359             IEnumerable<Expression> enumerable = this.VisitExpressionList(na.Expressions);
360             if (enumerable == na.Expressions)
361             {
362                 return na;
363             }
364             if (na.NodeType == ExpressionType.NewArrayInit)
365             {
366                 return Expression.NewArrayInit(na.Type.GetElementType(), enumerable);
367             }
368             return Expression.NewArrayBounds(na.Type.GetElementType(), enumerable);
369         }
370         protected virtual Expression VisitInvocation(InvocationExpression iv)
371         {
372             IEnumerable<Expression> enumerable = this.VisitExpressionList(iv.Arguments);
373             Expression expression = this.Visit(iv.Expression);
374             if (enumerable != iv.Arguments || expression != iv.Expression)
375             {
376                 return Expression.Invoke(expression, enumerable);
377             }
378             return iv;
379         }
380     }
381 }