Data Validation in DataGrid in silverlight 3 Application

Introduction

We have already seen how to validate input data using DataAnnotations and DataInput controls. In this article we will see how it can be implemented to a DataGrid. That means validating user input in DataGrid.

Creating Silverlight Project

Fire up Visual Studio 2008 and create a Silverlight Application. Name it as DataValidationDataGridSL3.



Now we need a DataGrid to display sample data.

Go ahead and add it and name it as MyDataGrid.



Now we need to add a class which contains the properties of the sample data.

public class Users
{
public string Name { get; set; }
public int Age { get; set; }
public string Gender { get; set; }
public string Country { get; set; }
}

DataAnnotation provides a developer friendly DataValidation techniques. So we need to add the assembly.



The ValidationException (belonging to System.ComponentModel.DataAnnotations ) thrown is displayed as Cell Validation Error.

Now that you have added the above assembly, use it in the Users.cs class and define the properties as required. As follows:

public class Users: INotifyPropertyChanged
{
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
#endregion

#region UserName

private string _UserName;

public string UserName

{

get { return _UserName; }

set

{

if (value.Length < 4)

{

throw new ValidationException("User Name should contain atleast 4 chars");

}

_UserName = value;

RaisePropertyChanged("UserName");

}

}

#endregion

#region Age

private int _Age;

public int Age

{

get { return _Age; }

set

{

_Age = value;

}

}

#endregion

#region Gender

private string _Gender;

public string Gender

{

get { return _Gender; }

set

{

_Gender = value;

}

}

#endregion

#region Country

private string _Country;

public string Country

{

get { return _Country; }

set

{

_Country = value;

}

}

#endregion

private void RaisePropertyChanged(string propertyName)

{

if (this.PropertyChanged != null)

{

this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

}

}

}

Now add some sample data in the MainPage constructor and bind the DataGrid's ItemSource to the sample data.

public MainPage()
{
InitializeComponent();

List<Users> myList = new List<Users>

{

new Users{ UserName="Hiro Nakamura", Age=24, Gender="M", Country="Japan"},

new Users{ UserName="Mohinder Suresh", Age=26, Gender="M", Country="India"},

new Users{ UserName="Claire Bennette", Age=20, Gender="F", Country="USA"},

new Users{ UserName="Matt Parkman", Age=30, Gender="M", Country="USA"},

new Users{ UserName="Nathan Patrelli", Age=30, Gender="M", Country="USA"},

new Users{ UserName="Peter Patrelli", Age=26, Gender="M", Country="USA"},

new Users{ UserName="Mica Sanders", Age=19, Gender="M", Country="USA"},

new Users{ UserName="Linderman", Age=56, Gender="M", Country="USA"},

new Users{ UserName="Ando", Age=24, Gender="M", Country="Japan"},

new Users{ UserName="Maya", Age=24, Gender="F", Country="Mexico"},

new Users{ UserName="Angela Patrelli", Age=26, Gender="F", Country="USA"},

new Users{ UserName="Niki Sanders", Age=26, Gender="F", Country="USA"},

};

MyDataGrid.ItemsSource = myList;

}

That's it run your application and try to change the first name and keep it empty or enter less than 4 characters. It will throw you a ValidationException. As follows:



Try for other columns as required.

Enjoy Coding.