我想使用LINQ表达式设置私有字段。我有以下代码：
//parameter "target", the object on which to set the field `field`
ParameterExpression targetExp = Expression.Parameter(typeof(object), "target");
//parameter "value" the value to be set in the `field` on "target"
ParameterExpression valueExp = Expression.Parameter(typeof(object), "value");
//cast the target from object to its correct type
Expression castTartgetExp = Expression.Convert(targetExp, type);
//cast the value to its correct type
Expression castValueExp = Expression.Convert(valueExp, field.FieldType);
//the field `field` on "target"
MemberExpression fieldExp = Expression.Field(castTartgetExp, field);
//assign the "value" to the `field`
BinaryExpression assignExp = Expression.Assign(fieldExp, …