Built-in Dock State Persistence

Since the Q1 2013 release of Telerik® UI for ASP.NET AJAX, the RadDockLayout provides a built-in long-term persistence of RadDocks’ states. This means that the layout of the docks can be saved when a page is closed and opened, without necessarily handling the server-side events SaveDockLayout and LoadDockLayout of RadDockLayout.

The built-in dock state persistence is enabled by setting the property EnableLayoutPersistence to true. There are several options for the data repository that will be used for storing the state:

• Cookies - The dock state is stored in a cookie. This provider is enabled by setting the property LayoutPersistenceRepositoryType to Cookies. It is not recommended for use when there are a lot of docks on the page due to the 4KB size limit of a cookie.If this limit is exceeded, the state of the controls will not be persisted correctly.

• FileSystem - The dock state is stored in a file that resides in the App_Data folder of the project. This provider is enabled by setting the property LayoutPersistenceRepositoryType to FileSystem. If the property LayoutRepositoryID (described below) is configured, its value will be used for naming the file with the state data.

• Custom - The dock state is stored in a custom storage provider. This provider is enabled by setting the property LayoutPersistenceRepositoryType to Custom, creating a class that implements the interfaceIStateStorageProvider and setting an instance of this class to the property StorageProvider of RadDockLayout. The methods LoadStateFromStorage and SaveStateToStorage of the interface need to be implemented. This is demonstrated in the following code sample that uses the database table DockStates:

<telerik:RadDockLayout runat="server" ID="RadDockLayout1" EnableLayoutPersistence="true" LayoutPersistenceRepositoryType="Custom" 
    LayoutRepositoryID="CustomLayout">
    <telerik:RadDockZone runat="server" ID="RadDockZone1" Width="300" MinHeight="200">
        <telerik:RadDock RenderMode="Lightweight" runat="server" ID="RadDock1" Title="RadDock 1" Width="300"></telerik:RadDock>
        <telerik:RadDock RenderMode="Lightweight" runat="server" ID="RadDock2" Title="RadDock 2" Width="300"></telerik:RadDock>
    </telerik:RadDockZone>
    <telerik:RadDockZone runat="server" ID="RadDockZone2" Width="300" MinHeight="200">
    </telerik:RadDockZone>
</telerik:RadDockLayout>

using System;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using Telerik.Web.UI.PersistenceFramework;

public partial class DockStetePersistanceDemo : System.Web.UI.Page
{
    protected void Page_Init(object sender, EventArgs e)
    {
        RadDockLayout1.StorageProvider = new CustomLayoutStorage();
    }
}

public class CustomLayoutStorage : IStateStorageProvider
{
    public string LoadStateFromStorage(string key)
    {
        using (var conn = GetConnection())
        {
            conn.Open();
            using (var cmd = new SqlCommand("SELECT [state] FROM DockStates where [Key] = @Key", conn))
            {
                cmd.Parameters.Add(new SqlParameter("Key", key));
                string dockStateFromDB = cmd.ExecuteScalar().ToString();

                return dockStateFromDB;
            }
        }
    }

    public void SaveStateToStorage(string key, string serializedState)
    {
        using (var conn = GetConnection())
        {
            conn.Open();
            using (var updateCmd = new SqlCommand("UPDATE DockStates SET [state]=@DockState WHERE [Key]=@Key", conn))
            {
                SetDockStateParameters(updateCmd, key, serializedState);

                int updatedRowsCount = updateCmd.ExecuteNonQuery();
                if (updatedRowsCount == 0)
                {
                    using (var insertCmd = new SqlCommand("INSERT INTO DockStates ([Key], [state]) VALUES (@Key, @DockState)", conn))
                    {
                        SetDockStateParameters(insertCmd, key, serializedState);
                        insertCmd.ExecuteNonQuery();
                    }
                }
            }
        }
    }

    private void SetDockStateParameters(SqlCommand cmd, string key, string serializedState)
    {
        cmd.Parameters.Add(new SqlParameter("@Key", key));
        cmd.Parameters.Add(new SqlParameter("@DockState", serializedState));
    }

    private SqlConnection GetConnection()
    {
        return new SqlConnection(ConfigurationManager.ConnectionStrings["dockPersistDB"].ConnectionString);
    }
}

Imports Telerik.Web.UI.PersistenceFramework
Imports System.Data.SqlClient

Partial Class DockStetePersistanceDemoVB
    Inherits System.Web.UI.Page

    Protected Sub Page_Init(sender As Object, e As EventArgs) Handles Me.Init
        RadDockLayout1.StorageProvider = New CustomLayoutStorage()
    End Sub

End Class

Public Class CustomLayoutStorage
    Implements IStateStorageProvider
    Public Function LoadStateFromStorage(key As String) As String
        Using conn = GetConnection()
            conn.Open()
            Using cmd = New SqlCommand("SELECT [state] FROM DockStates where [Key] = @Key", conn)
                cmd.Parameters.Add(New SqlParameter("Key", key))
                Dim dockStateFromDB As String = cmd.ExecuteScalar().ToString()

                Return dockStateFromDB
            End Using
        End Using
    End Function

    Public Sub SaveStateToStorage(key As String, serializedState As String)
        Using conn = GetConnection()
            conn.Open()
            Using updateCmd = New SqlCommand("UPDATE DockStates SET [state]=@DockState WHERE [Key]=@Key", conn)
                SetDockStateParameters(updateCmd, key, serializedState)

                Dim updatedRowsCount As Integer = updateCmd.ExecuteNonQuery()
                If updatedRowsCount = 0 Then
                    Using insertCmd = New SqlCommand("INSERT INTO DockStates ([Key], [state]) VALUES (@Key, @DockState)", conn)
                        SetDockStateParameters(insertCmd, key, serializedState)
                        insertCmd.ExecuteNonQuery()
                    End Using
                End If
            End Using
        End Using
    End Sub

    Private Sub SetDockStateParameters(cmd As SqlCommand, key As String, serializedState As String)
        cmd.Parameters.Add(New SqlParameter("@Key", key))
        cmd.Parameters.Add(New SqlParameter("@DockState", serializedState))
    End Sub

    Private Function GetConnection() As SqlConnection
        Return New SqlConnection(ConfigurationManager.ConnectionStrings("dockPersistDB").ConnectionString)
    End Function
End Class

Note that the value of LayoutRepositoryID is available via the key parameter of the above methods and can be included the custom storage provider implementation.

The LoadDockLayout also provides a property LayoutRepositoryID which can be used for storing individual dock states that depend on the value of the property, e.g. for storing a unique dock state for every user in a website.

If you are creating the RadDock, RadDockZone and/or RadDockLayout programmatically, you must use the Page_Init event. For more details about the server lifecycle of the control and what each event is suitable for, review the RadDock Lifecycle article.