是否可以初始化控件的列表标记中的属性？

发布于 2024-07-21 04:26:58 字数 586 浏览 7 评论 0原文

假设我们有以下内容：

public enum RenderBehaviors
{
    A,
    B,
    C,
}

public class MyControl : Control
{
    public List<RenderBehaviors> Behaviors { get; set; }

    protected override void Render(HtmlTextWriter writer)
    {
        // output different markup based on behaviors that are set
    }
}

是否可以在 ASPX/ASCX 标记中初始化 Behaviours 属性？即：

<ns:MyControl runat="server" ID="ctl1" Behaviors="A,B,C" />

在这种情况下，子类化不是一个选项（行为的实际意图与此示例略有不同）。当我尝试以这种方式初始化属性时，WebForms 会生成解析器错误。同样的问题也适用于其他列表类型（int、字符串）。

原文

Let's say we have the following:

public enum RenderBehaviors
{
    A,
    B,
    C,
}

public class MyControl : Control
{
    public List<RenderBehaviors> Behaviors { get; set; }

    protected override void Render(HtmlTextWriter writer)
    {
        // output different markup based on behaviors that are set
    }
}

Is it possible to initialize the Behaviors property in the ASPX/ASCX markup? i.e.:

<ns:MyControl runat="server" ID="ctl1" Behaviors="A,B,C" />

Subclassing is not an option in this case (the actual intent of the Behaviors is slightly different than this example). WebForms generates a parser error when I try to initialize the property in this way. The same question could be applied to other List types (int, strings).

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黑凤梨 2024-07-28 04:26:58

经过进一步研究，我发现 WebForms 确实使用了 TypeConverter（如果它能找到的话）。类型或属性需要正确修饰，详见相关问题。

我最终实现了类似的东西：

public class MyControl : Control
{
    private readonly HashSet<RenderBehaviors> coll = new HashSet<RenderBehaviors>();

    public IEnumerable<RenderBehaviors> Behaviors { get { return coll; } }

    public string BehaviorsList
    {
        get { return string.Join(',', coll.Select(b => b.ToString()).ToArray()); }
        set
        {
            coll.Clear();
            foreach (var b in value.Split(',')
                .Select(s => (RenderBehvaior)Enum.Parse(typeof(RenderBehavior), s)))
            {
                coll.Add(b);
            }
        }
    }
}

After researching this further, I found that WebForms does use a TypeConverter if it can find it. The type or the property needs to be decorated properly, as detailed in this related question.

I wound up implementing something similar to this:

public class MyControl : Control
{
    private readonly HashSet<RenderBehaviors> coll = new HashSet<RenderBehaviors>();

    public IEnumerable<RenderBehaviors> Behaviors { get { return coll; } }

    public string BehaviorsList
    {
        get { return string.Join(',', coll.Select(b => b.ToString()).ToArray()); }
        set
        {
            coll.Clear();
            foreach (var b in value.Split(',')
                .Select(s => (RenderBehvaior)Enum.Parse(typeof(RenderBehavior), s)))
            {
                coll.Add(b);
            }
        }
    }
}

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