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Редактировал(а) Alexandr Fokin 2025/05/13 13:04

От версии 2.8
отредактировано Alexandr Fokin
на 2023/10/27 13:49
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К версии 2.11
отредактировано Alexandr Fokin
на 2025/05/13 13:02
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... ... @@ -14,7 +14,7 @@
14 14  How do I set a field value in an C# Expression tree?
15 15  [[https:~~/~~/stackoverflow.com/questions/321650/how-do-i-set-a-field-value-in-an-c-sharp-expression-tree>>https://stackoverflow.com/questions/321650/how-do-i-set-a-field-value-in-an-c-sharp-expression-tree]]
16 16  )))
17 -|(% style="width:394px" %)Вызов конструктора|(% style="width:1090px" %){{code language="c#"}}var constructorInfo = type.GetConstructors().First(e => e.Attributes.HasFlag(MethodAttributes.Public));
17 +|(% style="width:394px" %)Типизированый вызов конструктора|(% style="width:1090px" %){{code language="c#"}}var constructorInfo = type.GetConstructors().First(e => e.Attributes.HasFlag(MethodAttributes.Public));
18 18  var constructorParameter1 = Expression.Parameter(typeof(bool));
19 19  var constructorExp = Expression.New(constructorInfo, constructorParameter1);
20 20  
... ... @@ -28,9 +28,109 @@
28 28  How do you call a constructor via an expression tree on an existing object?
29 29  [[https:~~/~~/stackoverflow.com/questions/16363838/how-do-you-call-a-constructor-via-an-expression-tree-on-an-existing-object>>https://stackoverflow.com/questions/16363838/how-do-you-call-a-constructor-via-an-expression-tree-on-an-existing-object]]
30 30  )))
31 -|(% style="width:394px" %)Generic enum to int|(% style="width:1090px" %)How do I cast a generic enum to int?
32 -[[https:~~/~~/stackoverflow.com/questions/16960555/how-do-i-cast-a-generic-enum-to-int>>https://stackoverflow.com/questions/16960555/how-do-i-cast-a-generic-enum-to-int]]
31 +|(% style="width:394px" %)Нетипизированый вызов|(% style="width:1090px" %)(((
32 +|{{code language="c#"}}public delegate object ConstructorDelegate(object[]? Args);
33 33  
34 +public static ConstructorDelegate GetConstructorWithArgsDelegate(
35 + ConstructorInfo constructorInfo)
36 +{
37 +ParameterExpression constructorParameters = Expression.Parameter(typeof(object?[]));
38 +
39 +Expression[] parameterExpressions;
40 +{
41 + ParameterInfo[] parametersInfos = constructorInfo.GetParameters();
42 + parameterExpressions = new Expression[parametersInfos.Length];
43 +
44 + for (int i = 0; i < parametersInfos.Length; i++)
45 + {
46 + ConstantExpression ithIndex = Expression.Constant(i);
47 + BinaryExpression ithParameter = Expression.ArrayIndex(
48 + constructorParameters,
49 + ithIndex);
50 + UnaryExpression unboxedIthParameter = Expression.Convert(
51 + ithParameter,
52 + parametersInfos[i].ParameterType
53 + );
54 + parameterExpressions[i] = unboxedIthParameter;
55 + }
56 +}
57 +
58 +NewExpression constructorCallExp = Expression.New(
59 + constructorInfo,
60 + parameterExpressions);
61 +
62 +var convertResultExp = Expression.Convert(
63 + constructorCallExp,
64 + typeof(object)
65 + );
66 +
67 +var constructorHandler = Expression
68 + .Lambda<ConstructorDelegate>(
69 + convertResultExp,
70 + constructorParameters
71 + )
72 + .Compile();
73 +
74 +return constructorHandler;
75 +}{{/code}}|C# Expression tree: object array to Expression.New() parameters
76 +[[https:~~/~~/stackoverflow.com/questions/67968927/c-sharp-expression-tree-object-array-to-expression-new-parameters>>https://stackoverflow.com/questions/67968927/c-sharp-expression-tree-object-array-to-expression-new-parameters]]
77 +|{{code language="c#"}}public delegate object? MethodDelegate(object instance, object[]? Args);
78 +
79 +public static MethodDelegate GetMethodWithArgsDelegate(
80 + MethodInfo methodInfo,
81 + Type instanceType)
82 +{
83 +ParameterExpression instanceParameter = Expression.Parameter(typeof(object));
84 +ParameterExpression methodParameters = Expression.Parameter(typeof(object?[]));
85 +
86 +Expression instanceExp;
87 +Expression[] parameterExpressions;
88 +{
89 + instanceExp = Expression.Convert(instanceParameter, instanceType);
90 +
91 + ParameterInfo[] parametersInfos = methodInfo.GetParameters();
92 + parameterExpressions = new Expression[parametersInfos.Length];
93 +
94 + for (int i = 0; i < parametersInfos.Length; i++)
95 + {
96 + ConstantExpression ithIndex = Expression.Constant(i);
97 + BinaryExpression ithParameter = Expression.ArrayIndex(
98 + methodParameters,
99 + ithIndex);
100 + UnaryExpression unboxedIthParameter = Expression.Convert(
101 + ithParameter,
102 + parametersInfos[i].ParameterType
103 + );
104 + parameterExpressions[i] = unboxedIthParameter;
105 + }
106 +}
107 +
108 +var callExpression = Expression.Call(
109 + instanceExp,
110 + methodInfo,
111 + parameterExpressions
112 + );
113 +
114 +var convertResultExp = Expression.Convert(
115 + callExpression,
116 + typeof(object)
117 + );
118 +
119 +var callHandler = Expression
120 + .Lambda<MethodDelegate>(
121 + convertResultExp,
122 + instanceParameter,
123 + methodParameters
124 + )
125 + .Compile();
126 +
127 +return callHandler;
128 +}{{/code}}|
129 +
130 +
131 +)))
132 +|(% style="width:394px" %)[[Generic enum to int>>doc:.Generic enum to int.WebHome]]|(% style="width:1090px" %)
133 +
34 34  ==== ====
35 35  
36 36  ==== ====