NHibernate:枚举以列出并将值存储在数据库中 [英] NHibernate: Enum to list and store values in database

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问题描述

我正在使用enum和自定义的Selector类来帮助在单选按钮，下拉菜单，复选框等之间进行选择.我正在使用NHibernate.通过单选(单选按钮，下拉菜单)，来自属性[Display(Name = "[Some Text]")]的值将被填充到数据库表中(注意:我正在使用扩展名来使用Display(Name)).但是，对于多个选择(复选框，多列表)，我无法弄清楚如何将enum选择的值添加到数据库中.

I am using enum's and a custom Selector class to help choose between radiobuttons, dropdowns, checkboxes, etc. I am using NHibernate. With a single selection (radiobuttons, dropdowns), the value from attribute [Display(Name = "[Some Text]")] will be populated in the database table (NOTE: I am using an extension to use Display(Name)). However, with multiple selections (checkboxes, multilist), I cannot figure out how to get the values of the enum selections into the database.

这是模型的一部分(每个部分都位于单独的文件中)(我给了它们通用名称，以免进一步混淆问题):

Here are parts of my model (each in separate files) ( I gave them generic names so as not to further confuse the issue):

public enum MyEnum
{
    [Display(Name = "Text for enum1")]
    enum1,
    //Left out 2 - 10 for brevity
    [Display(Name = "Text for enum10")]
    enum10
}
...
public class MyEnumSelectorAttribute : SelectorAttribute
{
    public override IEnumerable<SelectListItem> GetItems()
    {
        return Selector.GetItemsFromEnum<MyEnum>();
    }
}
...
[Display(Name = "This is a checkboxlist (select one or more check boxes)?")]
[MyEnumSelector(BulkSelectionThreshold = 10)]
public virtual List<string> MyEnumCheckBox { get; set; }
...
public List<string> MyEnumCheckBox
{
    get { return Record.MyEnumCheckBox; }
    set { Record.MyEnumCheckBox = value; }
}

这是Selector.cs类(在与问题相关的情况下)，可帮助选择单选按钮，复选框，下拉菜单等:

And here is the Selector.cs class (in case it's relevant to the problem) that help's to choose radiobuttons, checkboxes, dropdowns, etc.:

public class Selector
{
    public IEnumerable<SelectListItem> Items { get; set; }

    public string OptionLabel { get; set; }

    public bool AllowMultipleSelection { get; set; }

    public int BulkSelectionThreshold { get; set; }

    public static string GetEnumDescription(string value, Type enumType)
    {
        var fi = enumType.GetField(value.ToString());
        var display = fi
            .GetCustomAttributes(typeof(DisplayAttribute), false)
            .OfType<DisplayAttribute>()
            .FirstOrDefault();
        if (display != null)
        {
            return display.Name;
        }
        return value;
    }

    public static IEnumerable<SelectListItem> GetItemsFromEnum<T>
        (T selectedValue = default(T)) where T : struct
    {
        return from name in Enum.GetNames(typeof(T))
               let enumValue = Convert.ToString((T)Enum.Parse
                   (typeof(T), name, true))

               select new SelectListItem
               {
                   Text = GetEnumDescription(name, typeof(T)),
                   Value = enumValue,
                   Selected = enumValue.Equals(selectedValue)
               };
    }
}

public static class SelectorHelper
{
    public static IEnumerable<SelectListItem> ToSelectList
        (this IEnumerable data)
    {
        return new SelectList(data);
    }

    public static IEnumerable<SelectListItem> ToSelectList
        (this IEnumerable data, string dataValueField, 
        string dataTextField)
    {
        return new SelectList(data, dataValueField, dataTextField);
    }

    public static IEnumerable<SelectListItem> ToSelectList<T>
        (this IEnumerable<T> data, Expression<Func<T, object>> 
        dataValueFieldSelector, Expression<Func<T, string>> 
        dataTextFieldSelector)
    {
        var dataValueField = dataValueFieldSelector.ToPropertyInfo().Name;
        var dataTextField = dataTextFieldSelector.ToPropertyInfo().Name;
        return ToSelectList(data, dataValueField, dataTextField);
    }
}

Selector类与模板Selector.cshtml配对，该模板具有一些逻辑以找出要选择的对象(单选按钮，复选框等).

The Selector class is paired with a template Selector.cshtml that has some logic to figure out which to pick (radiobutton, checkboxes, etc.).

尝试List<string>，List<MyEnum>，IList<string>，IList<MyEnum>，IEnumerable<MyEnum>和IEnumerable<MyEnum>时遇到各种错误.由于复选框或多重列表使用List<string>，因此仅会出现此错误.例如，下拉菜单可以正常工作而不会出现错误.这是一个示例下拉模型(可以重复使用上面的enum)，该模型可以工作，并将允许通过NHibernate映射到数据库:

I am getting various errors trying either List<string>, List<MyEnum>, IList<string>, IList<MyEnum>, IEnumerable<MyEnum> and IEnumerable<MyEnum>. This error only comes with checkboxes or multilists since they use List<string>. Dropdowns, for example, work fine with no errors. Here is a sample dropdown model (can reuse enum above) that works and will allow mapping to the DB through NHibernate:

[Required(ErrorMessage = "Please select one option")]
[Display(Name = "This is a dropdown list (select one option)?")]
[MyEnumSelector(BulkSelectionThreshold = 0)] //0 selects dropdown
public virtual MyEnum? MyEnumDropDown { get; set; }

public MyEnum? MyEnumDropDown
    {
        get { return Record.MyEnumDropDown; }
        set { Record.MyEnumDropDown = value; }
    }

根据我的尝试，这是我遇到的一些错误:

Here are some of the errors I am getting based on what I've tried:

List<string>错误:

List<string> error:

NHibernate.Transaction.ITransactionFactory-DTC事务预备阶段失败 NHibernate.PropertyAccessException:无效的类型转换(检查属性类型不匹配的映射)； MyNameSpace.Models.MyRecord的设置方法---> System.InvalidCastException:无法转换类型为"NHibernate.Collection.Generic.PersistentGenericBag 1[System.String]' to type 'System.Collections.Generic.List 1 [System.String]"的对象.

NHibernate.Transaction.ITransactionFactory - DTC transaction prepre phase failed NHibernate.PropertyAccessException: Invalid Cast (check your mapping for property type mismatches); setter of MyNameSpace.Models.MyRecord ---> System.InvalidCastException: Unable to cast object of type 'NHibernate.Collection.Generic.PersistentGenericBag1[System.String]' to type 'System.Collections.Generic.List1[System.String]'.

List<MyEnum>错误:

List<MyEnum> error:

NHibernate.Transaction.ITransactionFactory-DTC事务预备阶段失败 System.InvalidCastException:无法转换类型为"System.Collections.Generic.List 1[MyNameSpace.Models.MyEnum]' to type 'System.Collections.Generic.ICollection 1 [System.String]"的对象.

NHibernate.Transaction.ITransactionFactory - DTC transaction prepre phase failed System.InvalidCastException: Unable to cast object of type 'System.Collections.Generic.List1[MyNameSpace.Models.MyEnum]' to type 'System.Collections.Generic.ICollection1[System.String]'.

IList<string>错误:

IList<string> error:

NHibernate.AdoNet.AbstractBatcher-无法执行命令:INSERT INTO MyEnumCheckBox(MyRecord_id，Value)VALUES(@ p0，@ p1) System.Data.SqlServerCe.SqlCeException(0x80004005):指定的表不存在. [MyEnumCheckBox]

NHibernate.AdoNet.AbstractBatcher - Could not execute command: INSERT INTO MyEnumCheckBox (MyRecord_id, Value) VALUES (@p0, @p1) System.Data.SqlServerCe.SqlCeException (0x80004005): The specified table does not exist. [ MyEnumCheckBox ]

我尝试的其他变体是类似的错误，除了如果使用<MyEnum>会显示如下错误:

The other variations I tried were similar errors, except that if I used <MyEnum> it would show an error like this:

System.Collections.Generic.List 1[MyNameSpace.Models.MyEnum]' to type 'System.Collections.Generic.ICollection 1 [System.String]'.

System.Collections.Generic.List1[MyNameSpace.Models.MyEnum]' to type 'System.Collections.Generic.ICollection1[System.String]'.

在尝试使用NHibernate插入多个选定的enum时，在这种情况下如何使用enum的想法?

Any thoughts on how to use enum's in this scenario when trying to insert multiple selected enums using NHibernate?

NHibernate:枚举以列出并将值存储在数据库中 [英] NHibernate: Enum to list and store values in database

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NHibernate:枚举以列出并将值存储在数据库中 [英] NHibernate: Enum to list and store values in database

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