ConstraintConverter.cs

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using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Reflection;
 
namespace System.Data;
 
internal sealed class ConstraintConverter : ExpandableObjectConverter
{
    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (!(destinationType == typeof(InstanceDescriptor)))
        {
            return base.CanConvertTo(context, destinationType);
        }
        return true;
    }
 
    public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
    {
        if (destinationType == null)
        {
            throw new ArgumentNullException("destinationType");
        }
        if (destinationType == typeof(InstanceDescriptor) && value is Constraint)
        {
            if (value is UniqueConstraint)
            {
                UniqueConstraint uniqueConstraint = (UniqueConstraint)value;
                ConstructorInfo constructor = typeof(UniqueConstraint).GetConstructor(new Type[3]
                {
                    typeof(string),
                    typeof(string[]),
                    typeof(bool)
                });
                if (constructor != null)
                {
                    return new InstanceDescriptor(constructor, new object[3] { uniqueConstraint.ConstraintName, uniqueConstraint.ColumnNames, uniqueConstraint.IsPrimaryKey });
                }
            }
            else
            {
                ForeignKeyConstraint foreignKeyConstraint = (ForeignKeyConstraint)value;
                ConstructorInfo constructor2 = typeof(ForeignKeyConstraint).GetConstructor(new Type[7]
                {
                    typeof(string),
                    typeof(string),
                    typeof(string[]),
                    typeof(string[]),
                    typeof(AcceptRejectRule),
                    typeof(Rule),
                    typeof(Rule)
                });
                if (constructor2 != null)
                {
                    return new InstanceDescriptor(constructor2, new object[7]
                    {
                        foreignKeyConstraint.ConstraintName,
                        foreignKeyConstraint.ParentKey.Table.TableName,
                        foreignKeyConstraint.ParentColumnNames,
                        foreignKeyConstraint.ChildColumnNames,
                        foreignKeyConstraint.AcceptRejectRule,
                        foreignKeyConstraint.DeleteRule,
                        foreignKeyConstraint.UpdateRule
                    });
                }
            }
        }
        return base.ConvertTo(context, culture, value, destinationType);
    }
}