I would like to have a generic validation-mechanism, implemented in all controls. Hear me out:
A class ValidationInformation for containing all sort of validation information for a certain field, property, cell, etc. which has properties likes:
It also has a virtual method like bool Validate(object entity, object value, out string validationError).
A base class ValidationInformationProvider for retrieving validation information from various sources. It has some abstract methods for retrieval, storing/caching information per cell/field/property.
This base class has the following subclasses:
Each provider is responsible for reading validation information from the source (DataTable, annotations on a property, etc.) and fill a ValidationInformation object.
Now the fun begins...
Each Telerik class, like RadGridView and/or subcomponents should get a method or event to retrieve ValidationInformation. When the event is not handled or the method returns null, the default behavior kicks in.
When ValidationInformation is provided, default behavior is overridden. Properties of editors van be set with values from ValidationInformation (like Minimum and Maximum of a GridViewDecimalColumnPlus or RadSpinEditorElement). At the end if editing the method ValidationInformation.Validate is called to validate the new value. The validation error can be used for popups, or tooltips, or an exception.
This way a user does not have to think where to set which property of any Telerik control for any validation. This way a RadPropertyGrid and RadGridView can work the same way when it comes to data validation, regardless of all editors which work in the background.