在 EF Code First Fluent API 中我可以编写如下内容：
modelBuilder.Entity<MyEntity>()
.Ignore(e => e.Property1);
modelBuilder.Entity<MyEntity>()
.Ignore(e => e.Property2);
如何忽略除一小部分属性之外的所有属性，如下所示：
modelBuilder.Entity<MyEntity>()
.IgnoreAllBut(e => e.ID, e => e.Important);
可以这样写扩展方法吗IgnoreAllBut?
这是草案，但有效：
public static void IgnoreAllBut<TStructuralType>(
this StructuralTypeConfiguration<TStructuralType> configuration,
params Expression<Func<TStructuralType, object>>[] includes)
where TStructuralType : class
{
var includeMembers = ConvertExpressionsToMembers(includes);
var type = typeof(TStructuralType);
var properties = type.GetProperties();
var typeParameter = Expression.Parameter(type);
var configurationType = configuration.GetType();
var ignoreMethod = configurationType.GetMethod("Ignore");
foreach (var property in properties)
{
if (!includeMembers.Any(member => member.Name == property.Name))
{
var propertyExpression = Expression.Property(typeParameter, property);
var lambdaExpression = Expression.Lambda(propertyExpression, typeParameter);
var genericIgnoreMethod = ignoreMethod.MakeGenericMethod(property.PropertyType);
var parameters = new object[] { lambdaExpression };
genericIgnoreMethod.Invoke(configuration, parameters);
}
}
}
private static List<MemberInfo> ConvertExpressionsToMembers<TStructuralType>(
Expression<Func<TStructuralType, object>>[] expressions)
{
var members = new List<MemberInfo>();
foreach (var lambda in expressions)
{
var expression = lambda.Body;
var memberExpression = expression as MemberExpression;
if (memberExpression == null)
{
var unaryExpression = expression as UnaryExpression;
memberExpression = unaryExpression.Operand as MemberExpression;
}
members.Add(memberExpression.Member);
}
return members;
}
感谢 DarkGray 提供链接中的代码question https://stackoverflow.com/questions/9621736/how-to-convert-propertyinfo-to-property-expression-and-use-it-to-invoke-generic.
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