设计时的 WinForms 组件属性

Posted 2023-02-23

【中文标题】设计时的 WinForms 组件属性

【英文标题】：WinForms component properties at Design time

【发布时间】：2017-09-16 03:26:20

【问题描述】：

我尝试编写自己的组件来更改某些控件属性。我的想法是我将这个组件从工具箱放到表单中，在设计器的属性窗口中我可以选择应该使用哪个控件，就像这样：

我的代码是：

public class ShapeForm : Component

    private int _shape;

    public ShapeForm()
    
        Shape = 20;
    

    [TypeConverter(typeof(ControlTypeConverter))]
    public Control TargetControl  get; set; 

    [Browsable(false)] // don't show in the property grid 
    public List<Control> Controls  get; private set; 

    public ContainerControl Target  get; set;  = null;

    public override ISite Site
    
        get  return base.Site; 
        set
        
            base.Site = value;

            IDesignerHost host = value?.GetService(
                typeof(IDesignerHost)) as IDesignerHost;
            IComponent componentHost = host?.RootComponent;
            if (componentHost is ContainerControl)
            
                Target = componentHost as ContainerControl;
                Controls = new List<Control>();
                foreach (Control control in (componentHost as ContainerControl).Controls)
                

                    Controls.Add(control);
                
                ;

            
        
    

    public class ControlTypeConverter : TypeConverter
    
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        
            // we only know how to convert from to a string
            return typeof(Control) == destinationType;
        

        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value,
            Type destinationType)
        
            if (typeof(string) == destinationType)
            
                Control control = value as Control;
                if (control != null)
                    return control;
            
            return "(none)";
        
    

    [
        Category("Shaping"),
        Description("Set corner shape radius"),
        Browsable(true)
    ]
    public int Shape
    
        set
        
            _shape = value;
            //SetShaping();
        
        get  return _shape; 
    


'

但我只得到一个元素，而不是像第一个屏幕截图那样以这种形式获得所有控件：

[]

【问题讨论】：

您已明确将其标记为不可浏览...如果我没记错，您还必须提供类型转换器。

不，它不会显示在下拉列表中。

【参考方案1】：

使用此代码；

[Browsable(true)]
[Editor(typeof(TestDesignProperty), typeof(UITypeEditor))]
[DefaultValue(null)]
public string SelectedObject  get; set; 

public class TestDesignProperty : UITypeEditor

    public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
    
        return UITypeEditorEditStyle.DropDown;
    

    public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
    

        var edSvc = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));
        ListBox lb = new ListBox();
        var form1 = (Form1) Activator.CreateInstance(typeof (Form1)); //Change with your form class
        foreach (Control control in form1.Controls)
        
            lb.Items.Add(control.Name);
        

        if (value != null)
        
            lb.SelectedItem = value;
        

        edSvc.DropDownControl(lb);

        value = (string)lb.SelectedItem;

        return value;
    

【讨论】：

感谢您的回答。现在我有一个问题，Form 类是未知的。首先将这个组件放到我现在的表单中。

第二个问题：所有这些控件都显示为一个字符串对象，我没有一个“+”开头的视线，以折叠属性树。