Custom Properties For Custom Controls

Question

I'm developing a set of custom controls. I have multiple properties that I would like to group together.

I know that I can do something like this:

[Category("HoverStyle"), Description("Specifies if the label will bold when the mouse is hovering.")]
public bool HoverBold { get; set; }

[Category("HoverStyle"), Description("Specifies if the label will italicize when the mouse is hovering.")]
public bool HoverItalicize { get; set; }

[Category("HoverStyle"), Description("Specifies if the label will underline when the mouse is hovering.")]
public bool HoverUnderline { get; set; }

But when you organize the property grid alphabetically, they will not appear in a group. I would like each of those properties to appear as properties of a struct just like the x- and y-coordinates appear under the Location property of controls.

I tried to create a struct such as this:

public struct HoverStyle
{
    public bool Bold { get; set; }
    public bool Italicize { get; set; }
    public bool Underline { get; set; }
}

But this doesn't behave the way I'm intending. Thanks for any help!

Minato · Accepted Answer

Although this isn't the answer for this exact scenario, the same solution applies. In this solution, I show how I've done what I had described above, but with a struct that defined a TopLeft, TopRight, BottomLeft, and BottomRight radius for controls that I'm drawing. I created my own struct and TypeConverter.

[Serializable]
[TypeConverter(typeof(CornerRadiiConverter))]
public struct CornerRadii
{
    private bool all;
    private int topLeft, topRight, bottomLeft, bottomRight;

    public readonly static CornerRadii Empty;

    [RefreshProperties(RefreshProperties.All)]
    public int All
    {
        get
        {
            if (!this.all)
                return -1;
            return this.topLeft;
        }
        set
        {
            if (!this.all || this.topLeft != value)
            {
                this.all = true;
                this.topLeft = value;
                this.topRight = value;
                this.bottomLeft = value;
                this.bottomRight = value;
            }
        }
    }

    [RefreshProperties(RefreshProperties.All)]
    public int TopLeft
    {
        get
        {
            return this.topLeft;
        }
        set
        {
            if (this.all || this.topLeft != value)
            {
                this.all = false;
                this.topLeft = value;
            }
        }
    }

    [RefreshProperties(RefreshProperties.All)]
    public int TopRight
    {
        get
        {
            if (this.all)
                return this.topLeft;
            return this.topRight;
        }
        set
        {
            if (this.all || this.topRight != value)
            {
                this.all = false;
                this.topRight = value;
            }
        }
    }

    [RefreshProperties(RefreshProperties.All)]
    public int BottomLeft
    {
        get
        {
            if (this.all)
                return this.topLeft;
            return this.bottomLeft;
        }
        set
        {
            if (this.all || this.bottomLeft != value)
            {
                this.all = false;
                this.bottomLeft = value;
            }
        }
    }

    [RefreshProperties(RefreshProperties.All)]
    public int BottomRight
    {
        get
        {
            if (this.all)
                return this.topLeft;
            return this.bottomRight;
        }
        set
        {
            if (this.all || this.bottomRight != value)
            {
                this.all = false;
                this.bottomRight = value;
            }
        }
    }

    static CornerRadii()
    {
        CornerRadii.Empty = new CornerRadii(0);
    }

    public CornerRadii(int all)
    {
        this.all = true;
        this.topLeft = all;
        this.topRight = all;
        this.bottomLeft = all;
        this.bottomRight = all;
    }

    public CornerRadii(int topLeft, int topRight, int bottomLeft, int bottomRight)
    {
        this.topLeft = topLeft;
        this.topRight = topRight;
        this.bottomLeft = bottomLeft;
        this.bottomRight = bottomRight;
        this.all = (this.topLeft != this.topRight || this.topLeft != this.bottomRight ? false : this.topLeft == this.bottomRight);
    }

    internal bool ShouldSerializeAll()
    {
        return this.all;
    }
}

public class CornerRadiiConverter : TypeConverter
{
    [TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
    public CornerRadiiConverter()
    {
    }

    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        if (sourceType == typeof(string))
        {
            return true;
        }
        return base.CanConvertFrom(context, sourceType);
    }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(InstanceDescriptor))
        {
            return true;
        }
        return base.CanConvertTo(context, destinationType);
    }

    public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
    {
        string str = value as string;
        if (str == null)
            return base.ConvertFrom(context, culture, value);
        str = str.Trim();
        if (str.Length == 0)
            return null;
        if (culture == null)
            culture = CultureInfo.CurrentCulture;
        char delimiter = culture.TextInfo.ListSeparator[0];
        string[] strArray = str.Split(new char[] { delimiter });
        int[] numArray = new int[strArray.Length];
        TypeConverter converter = TypeDescriptor.GetConverter(typeof(int));
        for (int i = 0; i < numArray.Length; i++)
            numArray[i] = (int)converter.ConvertFromString(context, culture, strArray[i]);
        if (numArray.Length != 4)
        {
            object[] objArray = new object[] { "value", str, "topLeft, topRight, bottomLeft, bottomRight" };
            throw new ArgumentException();
        }
        return new CornerRadii(numArray[0], numArray[1], numArray[2], numArray[3]);
    }

    public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
    {
        if (destinationType == null)
            throw new ArgumentNullException("destinationType");
        if (value is CornerRadii)
            if (destinationType == typeof(string))
            {
                CornerRadii cornerRadii = (CornerRadii)value;
                if (culture == null)
                    culture = CultureInfo.CurrentCulture;
                string str = string.Concat(culture.TextInfo.ListSeparator, " ");
                TypeConverter converter = TypeDescriptor.GetConverter(typeof(int));
                string[] strArrays = new string[4];
                strArrays[0] = converter.ConvertToString(context, culture, cornerRadii.TopLeft);
                strArrays[1] = converter.ConvertToString(context, culture, cornerRadii.TopRight);
                strArrays[2] = converter.ConvertToString(context, culture, cornerRadii.BottomLeft);
                strArrays[3] = converter.ConvertToString(context, culture, cornerRadii.BottomRight);
                return string.Join(str, strArrays);
            }
            if (destinationType == typeof(InstanceDescriptor))
            {
                CornerRadii cornerRadii1 = (CornerRadii)value;
                if (cornerRadii1.ShouldSerializeAll())
                {
                    ConstructorInfo constructor = typeof(CornerRadii).GetConstructor(new Type[] { typeof(int) });
                    object[] all = new object[] { cornerRadii1.All };
                    return new InstanceDescriptor(constructor, all);
                }
                Type type = typeof(CornerRadii);
                Type[] typeArray = new Type[] { typeof(int), typeof(int), typeof(int), typeof(int) };
                ConstructorInfo constructorInfo = type.GetConstructor(typeArray);
                object[] left = new object[] { cornerRadii1.TopLeft, cornerRadii1.TopRight, cornerRadii1.BottomLeft, cornerRadii1.BottomRight };
                return new InstanceDescriptor(constructorInfo, left);
            }
        return base.ConvertTo(context, culture, value, destinationType);
    }

    public override object CreateInstance(ITypeDescriptorContext context, IDictionary propertyValues)
    {
        if (context == null)
            throw new ArgumentNullException("context");
        if (propertyValues == null)
            throw new ArgumentNullException("propertyValues");
        CornerRadii value = (CornerRadii)context.PropertyDescriptor.GetValue(context.Instance);
        int item = (int)propertyValues["All"];
        if (value.All != item)
            return new CornerRadii(item);
        return new CornerRadii((int)propertyValues["TopLeft"], (int)propertyValues["TopRight"], (int)propertyValues["BottomLeft"], (int)propertyValues["BottomRight"]);
    }

    public override bool GetCreateInstanceSupported(ITypeDescriptorContext context)
    {
        return true;
    }

    public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
    {
        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(CornerRadii), attributes);
        string[] strArrays = new string[] { "All", "TopLeft", "TopRight", "BottomLeft", "BottomRight" };
        return properties.Sort(strArrays);
    }

    public override bool GetPropertiesSupported(ITypeDescriptorContext context)
    {
        return true;
    }
}

I will say that I don't really want to take to much credit for this, because this struct and TypeConverter are pretty much identical to the Padding struct and TypeConverter, just a few tweaks. You might be thinking that a radius for a corner can't be less than 0, and you're right! That is something I check when setting the property in the custom control, although as I'm writing this, I'm thinking that I can put it into the struct instead... we'll see.

Custom Properties For Custom Controls

Answers (2)

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