# Razor Validation Helpers

• Methods on the Validation property of the WebPage base class applied to all Razor pages:
  • .RequireField(string field, string errorMessage)
  • .Add(string field, params IValidator[] validators) and .Add(IEnumerable<string> fields, params IValidator[] validators)
• Static methods on the Validator factory class for creating different kinds of validators
  • .StringLength(int maxLength, int minLength=0, string errorMessage = null)
  • .Range(double minValue, double maxValue, string errorMessage = null)`
  • .Decimal(string errorMessage = null)
  • .Integer(string errorMessage = null)
  • .Url(string errorMessage = null)
  • .DateTime(string errorMessage = null)
• @Html.ValidationSummary() and @Html.ValidationMessage()

# Showing Images

@{
    Page.Title = "Manage Categories";
    Layout = "~/_SiteLayout.cshtml";

    var db = Database.Open("NW");
    var queryAllCategories = "SELECT CategoryID, CategoryName FROM Categories ORDER BY CategoryName";

    string categoryId = "1";
    var queryOneCategory = "SELECT CategoryID, CategoryName, Description, Picture, PictureMimeType FROM Categories WHERE CategoryID = @0";
    var foundCategory = db.QuerySingle(queryOneCategory, categoryId);
}

<div>
    <h1>Manage Categories</h1>

    <img src="data:@foundCategory.PictureMimeType;base64,@Convert.ToBase64String(foundCategory.Picture)" />
</div>