Insert, edit and delete data in a data table by ASPxGridView at runtime

It shows how to insert, edit and delete data in a data table by ASPxGridView. The data table and the
grid are created at runtime.

public partial class _Default : System.Web.UI.Page {

    private DataTable dataTable;

    protected void Page_Load(object sender, EventArgs e) {

        CreateGrid();

    }

    private DataTable CustomDataSourse {

        get {

            if (dataTable != null)

                return dataTable;

            dataTable = ViewState["CustomTable"] as DataTable;

            if (dataTable != null)

                return dataTable;

            dataTable = new DataTable("CustomDTable");

            dataTable.Columns.Add("Id", typeof(Int32));

            dataTable.PrimaryKey = new DataColumn[] { dataTable.Columns[0] };

            dataTable.Columns.Add("Data", typeof(string));

            dataTable.Rows.Add(0, "Data1");

            dataTable.Rows.Add(1, "Data2");

            dataTable.Rows.Add(2, "Data3");

            dataTable.Rows.Add(3, "Data4");

            dataTable.Rows.Add(4, "Data5");

            ViewState["CustomTable"] = dataTable;

            return dataTable;

        }

    }

    protected void grid_DataBinding(object sender, EventArgs e) {

        (sender as ASPxGridView).DataSource = CustomDataSourse;

    }

    protected void grid_DataBound(object sender, EventArgs e) {

        ASPxGridView g = sender as ASPxGridView;

        for (int i = 0; i < g.Columns.Count; i++) {

            GridViewDataTextColumn c = g.Columns[i] as GridViewDataTextColumn;

            if (c == null)

                continue;

            c.PropertiesTextEdit.ValidationSettings.RequiredField.IsRequired = true;

        }

    }

    protected void grid_RowDeleting(object sender, ASPxDataDeletingEventArgs e) {

        int id = (int)e.Keys[0];

        DataRow dr = CustomDataSourse.Rows.Find(id);

        dataTable.Rows.Remove(dr);

        ASPxGridView g = sender as ASPxGridView;

        UpdateData(g);

        e.Cancel = true;

    }

    protected void grid_RowUpdating(object sender, ASPxDataUpdatingEventArgs e) {

        int id = (int)e.OldValues["Id"];

        DataRow dr = CustomDataSourse.Rows.Find(id);

        dr[0] = e.NewValues["Id"];

        dr[1] = e.NewValues["Data"];

        ASPxGridView g = sender as ASPxGridView;

        UpdateData(g);

        g.CancelEdit();

        e.Cancel = true;

    }

    protected void grid_RowInserting(object sender, ASPxDataInsertingEventArgs e) {

        CustomDataSourse.Rows.Add(e.NewValues["Id"], e.NewValues["Data"]);

        ASPxGridView g = sender as ASPxGridView;

        UpdateData(g);

        g.CancelEdit();

        e.Cancel = true;

    }

    private void CreateGrid() {

        ASPxGridView grid = new ASPxGridView();

        grid.ID = "grid";

        this.Form.Controls.Add(grid);

        grid.EnableCallBacks = false;

        grid.KeyFieldName = "Id";

        grid.DataBinding += grid_DataBinding;

        grid.RowDeleting += grid_RowDeleting;

        grid.RowUpdating += grid_RowUpdating;

        grid.RowInserting += grid_RowInserting;

        grid.DataBound += grid_DataBound;

        grid.RowValidating += new ASPxDataValidationEventHandler(grid_RowValidating);

        grid.DataBind();

        if (!this.IsPostBack) {

            GridViewCommandColumn c = new GridViewCommandColumn();

            grid.Columns.Add(c);

            c.EditButton.Visible = true;

            c.UpdateButton.Visible = true;

            c.NewButton.Visible = true;

            c.DeleteButton.Visible = true;

            c.CancelButton.Visible = true;

        }

        GridViewDataTextColumn col = grid.Columns["Id"] as GridViewDataTextColumn;

        col.PropertiesTextEdit.ValidationSettings.RegularExpression.ValidationExpression
                                                                            = "\\d{1,9}";

    }

    void grid_RowValidating(object sender, ASPxDataValidationEventArgs e) {       

        int id = (int)e.NewValues["Id"];

        if ((!e.OldValues.Contains("Id") || ((int)e.OldValues["Id"] != id))

            && (CustomDataSourse.Rows.Find(id) != null)) {

            ASPxGridView grid = sender as ASPxGridView;

            e.Errors[grid.Columns["Id"]] =

String.Format("Column 'Id' is constrained to be unique.  Value '{0}' is already present.", id);

        }

    }

    private void UpdateData(ASPxGridView g) {

        ViewState["CustomTable"] = dataTable;

        g.DataBind();

    }

}