c# – Nancy模型绑定到子类

我们在Nancy的默认模型绑定器上遇到了问题.鉴于以下……

public class Foo
{
    public Foo()
    {
    }

    public string Name { get; set; }

    public Bar Bar { get; set; }
}

public class Bar
{
    public string Name { get; set; }
}

像……这样的元素

<input type="text" value="Name" />
<input type="text" value="Bar.Name" />

使用默认模型绑定器如此…

var foo = this.Bind< Foo>();

这正确绑定Foo.Name但无法绑定Foo.Bar.Name

有没有办法用默认绑定器启用这种绑定,还是我们需要自己滚动？如果有的话有什么好的例子吗？

解决方法

为什么不尝试这个.我很确定递归可以被优化,并且它会在不起作用的地方出现,并且它可以放在比IModelBinder更聪明的地方,但它基本上可以做你想要的.

/// <summary>
/// Sample model binder that manually binds customer models
/// </summary>
public class CustomModelBinder : IModelBinder
{
    /// <summary>
    /// Bind to the given model type
    /// </summary>
    /// <param name="context">Current context</param>
    /// <param name="modelType">Model type to bind to</param>
    /// <param name="blackList">Blacklisted property names</param>
    /// <returns>Bound model</returns>
    public object Bind(NancyContext context,Type modelType,params string[] blackList)
    {
        var parentObject = Activator.CreateInstance(modelType);

        foreach (var key in context.Request.Form)
        {
            var value = context.Request.Form[key];
            this.SetObjectValue(parentObject,modelType,key,value);
        }

        return parentObject;
    }

    /// <summary>
    /// Sets the object value.
    /// </summary>
    /// <param name="instance">The instance.</param>
    /// <param name="type">The type.</param>
    /// <param name="key">Name of the property.</param>
    /// <param name="propertyValue">The property value.</param>
    private void SetObjectValue(object instance,Type type,string key,string propertyValue)
    {
        if (key.Contains("."))
        {
            this.SetObjectValueDeep(instance,type,propertyValue);
        }

        PropertyInfo propertyInfo = type.GetProperty(key);
        if (propertyInfo == null)
        {
            return;
        }

        propertyInfo.SetValue(instance,Convert.ChangeType(propertyValue,propertyInfo.PropertyType),null);
    }

    /// <summary>
    /// Sets the object value derp.
    /// </summary>
    /// <param name="instance">The instance.</param>
    /// <param name="type">The type.</param>
    /// <param name="key">The key.</param>
    /// <param name="propertyValue">The property value.</param>
    private void SetObjectValueDeep(object instance,string propertyValue)
    {
        var propList = key.Split('.').ToList();

        PropertyInfo propertyInfo = type.GetProperty(propList.First());
        if (propertyInfo == null)
        {
            return;
        }

        var childObject = propertyInfo.GetValue(instance,null);

        if (childObject == null)
        {
            childObject = Activator.CreateInstance(propertyInfo.PropertyType);
            propertyInfo.SetValue(instance,childObject,null);
        }

        propList.RemoveAt(0);

        var newKey = propList.Aggregate(string.Empty,(current,prop) => current + (prop + ".")).TrimEnd('.');

        if (newKey.Contains("."))
        {
            this.SetObjectValueDeep(childObject,childObject.GetType(),newKey,propertyValue);
        }
        else
        {
            this.SetObjectValue(childObject,propertyValue);
        }
    }

    /// <summary>
    /// Determines whether this instance can bind the specified model type.
    /// </summary>
    /// <param name="modelType">Type of the model.</param>
    /// <returns>
    ///   <c>true</c> if this instance can bind the specified model type; otherwise,<c>false</c>.
    /// </returns>
    public bool CanBind(Type modelType)
    {
        return true;
    }
}