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.

1.gif

Now we need a DataGrid to display sample data.

Go ahead and add it and name it as MyDataGrid.

2.gif

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.

4.gif

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:

3.gif

Try for other columns as required.

Enjoy Coding.

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