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When you are about to submit a form, click OK on a dialog, etc. it’s a good idea to first verify if any of your controls have data validation errors associated with them. To learn how to hook up your controls to data validation please review Tip of the Day #22.

Silverlight 4 shipped with an interface called INotifyDataErrorInfo, and controls that previously supported validation by way of exceptions now support async validation through this interface. This laid the groundwork for RIA Services to offer a simple mechanism for adding validation errors to entities at arbitrary times and having the controls show those validation errors just like all others.

Animation Easing allows for you to apply built in animation functions to your Silverlight controls. The result is a variety of animation effects that make your controls move in a more realistic way. For example, you can add springiness to your controls, set how many times you want it to bounce when it hits a destination point, etc.

There are many articles about client side validation in WPF. Most of these articles are similar and use implementation of IDataErrorInfo interface on Model class. I have use some methods  already described in other articles just to show you how easy it is to implement client side validation in WPF using VAB. I have model class called Customer where I have implemented IDataErrorInfo.

Validation in Silverlight can get very complex pretty easy. The DataGrid control is the only control that does data validation automatically, but often you want to validate your own entry form. Values a user may enter in this form can be restricted by the customer and have to fit an exact fit to a list of requirements or you just want to prevent problems when saving the data to the database.

A ValidationResult represents a validation error condition, specifying the error message and, optionally, any member names that the error corresponds to.  If you use the [Required] attribute, the [Range] attribute, [StringLength], or any of the other provided ValidationAttribute classes, then ValidationResult instances are created to represent any validation failures.

Jeff Handley gives examples with using The System.ComponentModel.DataAnnotations.ValidationResult class.

The System.ComponentModel.DataAnnotations.ValidationResult class was created for RIA Services, and it was introduced in Silverlight 3.0 and then added into .NET 4.0.  A ValidationResult represents a validation error condition, specifying the error message and, optionally, any member names that the error corresponds to.  If you use the [Required] attribute, the [Range] attribute, [StringLength], or any of the other provided ValidationAttribute classes, then ValidationResult instances are created to represent any validation failures. 

I have notice that some people have problems about how to implement User Input validation when they don’t use controls like the DataForm or DataGrid  etc, and instead bind directly to a TextBox or other user input controls. In this post I will write about different ways to handle validations. In this post I will work with a simple View. I will later add a post where I will use some new Validation features in Siverlight 4 and where I also use the MVVM pattern and Commanding.

Fredrik Normén discusses various validation schemes in a simple View.

I have notice that some people have problems about how to implement User Input validation when they don’t use controls like the DataForm or DataGrid  etc, and instead bind directly to a TextBox or other user input controls. In this post I will write about different ways to handle validations. In this post I will work with a simple View. I will later add a post where I will use some new Validation features in Siverlight 4 and where I also use the MVVM pattern and Commanding.