DemoFormModel.cs

public class DemoFormModel
{
    [JsonSchemaExtensionData("label", "Label")]
    [JsonSchemaExtensionData("required", true)]
    [Description("The description appears below the input.")]
    [MinLength(3)]
    [MaxLength(50)]
    public string TextProperty { get; set; }

    public string StringProperty { get; set; }

    public bool BooleanProperty { get; set; }

    public int IntegerProperty { get; set; }

    [JsonSchemaExtensionData("xtype", "date")]
    public DateTime DateProperty { get; set; }

    [JsonSchemaExtensionData("xtype", "time")]
    public DateTime TimeProperty { get; set; }

    [JsonSchemaExtensionData("readonly", true)]
    public int ReadOnlyProperty { get; set; }

    [JsonSchemaExtensionData("xtype", "range")]
    [JsonSchemaExtensionData("min", 0)]
    [JsonSchemaExtensionData("max", 10)]
    [JsonSchemaExtensionData("step", 0.5)]
    public decimal RangeProperty { get; set; }

    [JsonSchemaExtensionData("optionsFromProperty", "stringOptions")]
    public string SelectedOption { get; set; }

    public List<string> StringOptions { get; set; }

    [JsonSchemaExtensionData("optionsFromProperty", "stringOptions")]
    [JsonSchemaExtensionData("nullOption", "None")]
    public string NullOptionProperty { get; set; }

    [JsonSchemaExtensionData("xtype", "textarea")]
    public string TextAreaProperty { get; set; }

    [JsonSchemaExtensionData("xtype", "textarea")]
    [JsonSchemaExtensionData("rows", "6")]
    [JsonSchemaExtensionData("maxrows", "50")]
    public string BigTextAreaProperty { get; set; }
}