具有 Type 类型属性的 UserControl [英] UserControl with property of type Type

问题描述

我正在使用 Type 类型的属性实现一个 UserControl.

I'm implementing a UserControl with a property of type Type.

public partial class MyUserControl: UserControl
{
    public MyUserControl()
    {
        InitializeComponent();
    }

    public Type PluginType { get; set; } = typeof(IPlugin);
}

在表单上放置 MyUserControl 时，我可以在设计器中看到 PluginType 属性，但我无法对其进行编辑.

When placing MyUserControl on a form I can see the PluginType property in the designer, but I cannot edit it.

如何使该属性可编辑?理想情况下，设计师会显示一个编辑器，我可以在其中选择我的程序集(或任何程序集)中的一种类型.有这样的编辑器吗?

How can I make this property editable? Ideally the designer would show an editor where I can pick one of the types in my assembly (or any assembly). Is there such an editor?

推荐答案

使用 Editor 属性告诉哪个类将用于编辑属性:

Use Editor attribute telling wich class will be used for editing of property:

[Editor("Mynamespace.TypeSelector , System.Design", typeof(UITypeEditor)), Localizable(true)]
public Type PluginType { get; set; }

定义一个 TypeSelector 类:

public class TypeSelector : UITypeEditor
{
    public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
    {
        if (context == null || context.Instance == null)
            return base.GetEditStyle(context);

        return UITypeEditorEditStyle.Modal;
    }
    public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
    {
        IWindowsFormsEditorService editorService;

        if (context == null || context.Instance == null || provider == null)
            return value;

        editorService = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));

        FormTypeSelector dlg = new FormTypeSelector();
        dlg.Value = value;
        dlg.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
        if (editorService.ShowDialog(dlg) == System.Windows.Forms.DialogResult.OK)
        {
            return dlg.Value;
        }
        return value;
    }
}

剩下的就是实现FormTypeSelector，您可以在其中选择一个类型并将其分配给Value 属性.在这里，您可以使用反射来过滤实现 IPlugin 的程序集中的类型.

Only thing remaining is to implement FormTypeSelector in which you can select a type and assign it to Value property. Here you can use reflection to filter the types in an assembly wich implements IPlugin.

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