public event SetInitialDashboardStateEventHandler SetInitialDashboardState

Public Event SetInitialDashboardState As SetInitialDashboardStateEventHandler

protected void ASPxDashboard1_SetInitialDashboardState(object sender, SetInitialDashboardStateEventArgs e) {
    var state = new DashboardState();
    // ...
    var itemState = new DashboardItemState("comboBoxDashboardItem");
    itemState.MasterFilterValues.Add(new object() { });
    state.Items.Add(itemState);
    // ...
    e.InitialState = state;
}

Protected Sub ASPxDashboard1_SetInitialDashboardState(ByVal sender As Object, ByVal e As SetInitialDashboardStateEventArgs)
    Dim state As New DashboardState()
    ' ...
    Dim itemState As New DashboardItemState("comboBoxDashboardItem")
    itemState.MasterFilterValues.Add(New Object() { })
    state.Items.Add(itemState)
    ' ...
    e.InitialState = state
End Sub

using DevExpress.DashboardCommon;
using DevExpress.DashboardWeb;
using System;
using System.Collections.Generic;

namespace WebDashboard_ManualDashboardState {
    public partial class Default : System.Web.UI.Page {
        protected void Page_Load(object sender, EventArgs e) {
        }

        protected void ASPxDashboard1_SetInitialDashboardState(object sender, SetInitialDashboardStateEventArgs e) {
            e.InitialState = InitializeDashboardState();
        }

        public DashboardState InitializeDashboardState() {
            DashboardState dashboardState = new DashboardState();

            DashboardParameterState parameterState = 
                new DashboardParameterState("countryParameter", "USA", typeof(string));

            DashboardItemState gridFilterState = new DashboardItemState("gridDashboardItem1");
            gridFilterState.MasterFilterValues.AddRange(new List<object[]>() {
                new string[1] { "Andrew Fuller" },
                new string[1] { "Laura Callahan" }
            }
            );

            DashboardItemState treemapDrilldownState = new DashboardItemState("treemapDashboardItem1");
            treemapDrilldownState.DrillDownValues.Add("Beverages");

            DashboardItemState rangeFilterState = new DashboardItemState("rangeFilterDashboardItem1");
            rangeFilterState.RangeFilterState.Selection = 
                new RangeFilterSelection(new DateTime(2015, 1, 1), new DateTime(2016, 1, 1));

            dashboardState.Parameters.Add(parameterState);
            dashboardState.Items.AddRange(new List<DashboardItemState>() {
                gridFilterState,
                treemapDrilldownState,
                rangeFilterState }
            );
            return dashboardState;
        }
    }
}

Imports DevExpress.DashboardCommon
Imports DevExpress.DashboardWeb
Imports System
Imports System.Collections.Generic

Namespace WebDashboard_ManualDashboardState

    Public Partial Class [Default]
        Inherits Web.UI.Page

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        End Sub

        Protected Sub ASPxDashboard1_SetInitialDashboardState(ByVal sender As Object, ByVal e As SetInitialDashboardStateEventArgs)
            e.InitialState = InitializeDashboardState()
        End Sub

        Public Function InitializeDashboardState() As DashboardState
            Dim dashboardState As DashboardState = New DashboardState()
            Dim parameterState As DashboardParameterState = New DashboardParameterState("countryParameter", "USA", GetType(String))
            Dim gridFilterState As DashboardItemState = New DashboardItemState("gridDashboardItem1")
            gridFilterState.MasterFilterValues.AddRange(New List(Of Object())() From {New String(0) {"Andrew Fuller"}, New String(0) {"Laura Callahan"}})
            Dim treemapDrilldownState As DashboardItemState = New DashboardItemState("treemapDashboardItem1")
            treemapDrilldownState.DrillDownValues.Add("Beverages")
            Dim rangeFilterState As DashboardItemState = New DashboardItemState("rangeFilterDashboardItem1")
            rangeFilterState.RangeFilterState.Selection = New RangeFilterSelection(New DateTime(2015, 1, 1), New DateTime(2016, 1, 1))
            dashboardState.Parameters.Add(parameterState)
            dashboardState.Items.AddRange(New List(Of DashboardItemState)() From {gridFilterState, treemapDrilldownState, rangeFilterState})
            Return dashboardState
        End Function
    End Class
End Namespace

using DevExpress.DashboardCommon;
using DevExpress.DashboardWeb;
using System;
using System.Web;

namespace WebDashboard_DashboardStateCookies {
    public partial class Default : System.Web.UI.Page {
        protected void Page_Load(object sender, EventArgs e) {            
        }

        protected void ASPxDashboard1_SetInitialDashboardState(object sender, SetInitialDashboardStateEventArgs e) {
            // Requests the "dashboardState" cookie:
            HttpCookie cookie = Request.Cookies["dashboardState"];
            if (cookie != null) {
                DashboardState dashboardState = new DashboardState();
                // Initializes a DevExpress.DashboardCommon.DashboardState object from the JSON state:
                dashboardState.LoadFromJson(HttpUtility.UrlDecode(cookie.Value));
                if (e.DashboardId == "dashboard1")
                    // Applies the initial dashboard state if it exists in cookies:
                    e.InitialState = dashboardState;
            }
        }
    }
}

Imports DevExpress.DashboardCommon
Imports DevExpress.DashboardWeb
Imports System
Imports System.Web

Namespace WebDashboard_DashboardStateCookies

    Public Partial Class [Default]
        Inherits UI.Page

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        End Sub

        Protected Sub ASPxDashboard1_SetInitialDashboardState(ByVal sender As Object, ByVal e As SetInitialDashboardStateEventArgs)
            ' Requests the "dashboardState" cookie:
            Dim cookie As HttpCookie = Request.Cookies("dashboardState")
            If cookie IsNot Nothing Then
                Dim dashboardState As DashboardState = New DashboardState()
                ' Initializes a DevExpress.DashboardCommon.DashboardState object from the JSON state:
                dashboardState.LoadFromJson(HttpUtility.UrlDecode(cookie.Value))
                ' Applies the initial dashboard state if it exists in cookies:
                If Equals(e.DashboardId, "dashboard1") Then e.InitialState = dashboardState
            End If
        End Sub
    End Class
End Namespace

function onBeforeRender(sender) {
    const dashboardControl = sender.GetDashboardControl();
    if (dashboardControl)
        dashboardControl.on('dashboardStateChanged', onDashboardStateChanged);
}

function onDashboardStateChanged(e) {
    // Set the number of days until the cookie should expire (exdays):
    const exdays = 1;
    const date = new Date();
    date.setTime(date.getTime() + (exdays * 24 * 60 * 60 * 1000));
    let expires = "expires=" + date.toUTCString();
    // Get the dashboard state:
    let dState = "dashboardState=" + e.component.getDashboardState() + ";";
    // Assign the cookie name (dashboardState), the cookie value, and the expires string to document.cookie:
    document.cookie = dState + expires + ";path=/";
}

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" 
    Inherits="WebDashboard_DashboardStateCookies.Default" %>

<%@ Register Assembly="DevExpress.Dashboard.v24.2.Web.WebForms, Version=24.2.13.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" 
    Namespace="DevExpress.DashboardWeb" TagPrefix="dx" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Web Dashboard Application</title>
    <script src="Script.js"></script>
</head>
<body>
    <form id="form1" runat="server">
    <div style="position:absolute; left:0; right:0; top:0; bottom:0;">
        <dx:ASPxDashboard ID="ASPxDashboard1" runat="server" 
            WorkingMode="ViewerOnly" 
            ClientInstanceName="webDashboard"
            IncludeDashboardIdToUrl="true"
            DashboardStorageFolder="~/App_Data/Dashboards" 
            Height="100%" Width="100%" 
            OnSetInitialDashboardState="ASPxDashboard1_SetInitialDashboardState">
            <ClientSideEvents BeforeRender="onBeforeRender"></ClientSideEvents>
        </dx:ASPxDashboard>
    </div>
    </form>
</body>
</html>