Manage Dashboard Parameters in WPF Dashboard Control

• Feb 08, 2023
• 6 minutes to read

This topic describes how to specify dashboard parameter values in the UI and in code.

Change Parameter Values in the UI

The DashboardControl provides a built-in Dashboard Parameters dialog, which allows users to change dashboard parameter values. This dialog is created automatically depending on the parameter type and its visibility settings.

To invoke the Dashboard Parameters dialog in the DashboardControl, click the Parameters button in the dashboard title. Change parameter values in the Dashboard Parameters dialog and click the Submit button to apply the changes.

The following image shows how to invoke the Dashboard Parameters dialog and change the parameter value:

To reset changes to the default values, click the Reset button.

Use the ShowParametersButton property to show or hide the Parameters button. To specify a custom Dashboard Parameters dialog template, use the ParametersTemplate property.

Manage Parameters in Code

Create Dashboard Parameters

You can create dashboard parameters and specify parameter settings in the Dashboard Viewer.

Use the Dashboard.Parameters property of Dashboard to access a collection of dashboard parameters.

To add a new dashboard parameter in code, create a parameter with the required settings and add it to the collection of dashboard parameters:

C#

Dashboard dashboard = new Dashboard();
dashboard.LoadFromXml(@"Dashboards\dashboard1.xml");
DashboardParameter parameter = new DashboardParameter("CategoryName", typeof(string), "Beverages");
dashboard.Parameters.Add(parameter);

VB.NET

Dim dashboard As New Dashboard()
dashboard.LoadFromXml("Dashboards\dashboard1.xml")
Dim parameter As New DashboardParameter("CategoryName", GetType(String), "Beverages")
dashboard.Parameters.Add(parameter)

The following code snippets show how to create dashboard parameters with different look-up settings.

No Look-Up

C#

DashboardParameter parameter1 = new DashboardParameter("Parameter1", typeof(string), "Beverages", "Select a category:", true, null);

VB.NET

Dim parameter1 As New DashboardParameter("Parameter1", GetType(String), "Beverages", "Select a category:", True, Nothing)

Static List

Use the StaticListLookUpSettings.Values property to specify the list of static values for the dashboard parameter.

C#

StaticListLookUpSettings settings = new StaticListLookUpSettings();
settings.Values = new string[] {"Beverages", "Condiments"};
DashboardParameter parameter2 = new DashboardParameter("Parameter2", typeof(string), "Beverages", "Select a category:", true, settings);

VB.NET

Dim settings As New StaticListLookUpSettings()
settings.Values = New String() {"Beverages", "Condiments"}
Dim parameter2 As New DashboardParameter("Parameter2", GetType(String), "Beverages", "Select a category:", True, settings)

Dynamic List

Use the DynamicListLookUpSettings.DataSource property to specify the data source for the dashboard parameter. Specify the required settings for the dashboard parameter.

C#

DynamicListLookUpSettings settings = new DynamicListLookUpSettings();
settings.DataSource = sqlDataSource;
settings.DataMember = "Categories";
settings.ValueMember = "CategoryID";
settings.DisplayMember = "CategoryName";
settings.SortOrder = DimensionSortOrder.Descending;
DashboardParameter parameter3 = new DashboardParameter("Parameter3", typeof(string), "1", "Select a category:", true, settings);

VB.NET

Dim settings As New DynamicListLookUpSettings()
settings.DataSource = sqlDataSource
settings.DataMember = "Categories"
settings.ValueMember = "CategoryID"
settings.DisplayMember = "CategoryName"
settings.SortOrder = DimensionSortOrder.Descending
Dim parameter3 As New DashboardParameter("Parameter3", GetType(String), "1", "Select a category:", True, settings)

Refer to the following article for information on where dashboard parameters can be used: Reference Dashboard Parameters in WinForms.

Change Parameter Values

Use the DashboardControl.CustomParameters event to change dashboard parameter values in the DashboardControl at runtime. For instance, you can forcibly change a parameter value when an end user changes this value in the Dashboard Parameters dialog.

The following code snippet shows how to change the dashboard parameter value (parameterState) at runtime:

C#

private void DashboardViewer_CustomParameters(object sender, CustomParametersEventArgs e) {
    var customParameter = e.Parameters.FirstOrDefault(p => p.Name == "parameterState");
    if (customParameter != null) {
        customParameter.Value = "Nevada";
    }
}

VB.NET

Public Sub OnCustomParameters(ByVal e As DevExpress.DashboardCommon.CustomParametersEventArgs)
    Dim customParameter = e.Parameters.FirstOrDefault(Function(p) p.Name = "parameterState")
    If customParameter IsNot Nothing Then
        customParameter.Value = "Nevada"
    End If
End Sub

Example - How to Manage Dashboard Parameters in Code

This example shows how to override a default or user-defined dashboard parameter value by changing it in the DashboardControl.CustomParameters event handler. The effective parameter value is hidden from the user. If you set the Visible property to false, the parameter is hidden from the Dashboard Parameters dialog.

In this example, the parameterState dashboard parameter is added to the dashboard in code. The Dashboard Parameters dialog displays a list of available parameter values and allows users to select a value from that list. The dashboard parameter itself is used to filter the data source. In the DashboardControl.CustomParameters event handler, we can change the value provided by the user before it is passed to the query. In the resulting application, the value defined in the DashboardControl.CustomParameters event is in effect.

View Example: WPF Dashboard - How to Manage Dashboard Parameters in Code

C#

using System;
using DevExpress.Mvvm.DataAnnotations;
using DevExpress.Mvvm;
using DevExpress.Mvvm.POCO;
using System.Linq;
using DevExpress.DashboardCommon;
using System.Collections.Generic;

namespace WPF_Dashboard_CustomParameters.ViewModels {
    [POCOViewModel]
    public class MyViewModel {
        protected MyViewModel() {
            //Dashboard = new SampleDashboard(); 
            Dashboard dashboard = new Dashboard();
            dashboard.LoadFromXml("Data\\SampleDashboard.xml");
            dashboard.Parameters.Add(CreateParameter());
            dashboard.DataSources[0].Filter = "[State] In (?parameterState)";
            Dashboard = dashboard;
        }
        public virtual DevExpress.DashboardCommon.Dashboard Dashboard { get; set; }
        private DashboardParameter CreateParameter() {
            DashboardParameter myDashboardParameter = new DashboardParameter();
            StaticListLookUpSettings staticListLookUpSettings1 = new StaticListLookUpSettings();
            myDashboardParameter.AllowMultiselect = true;
            // Parameter values displayed in the look-up editor.
            staticListLookUpSettings1.Values = new string[] { "Alabama", "Ohio", "Utah" };
            myDashboardParameter.LookUpSettings = staticListLookUpSettings1;
            myDashboardParameter.Name = "parameterState";
            myDashboardParameter.Type = typeof(string);
            // Default parameter value.
            myDashboardParameter.Value = new List<string> { "Ohio", "Utah" };

            return myDashboardParameter;
        }
        public void OnCustomParameters(DevExpress.DashboardCommon.CustomParametersEventArgs e) {
            var customParameter = e.Parameters.FirstOrDefault(p => p.Name == "parameterState");
            if (customParameter != null) {
                // Actual value used when retrieving data from the data source.
                customParameter.Value = "Nevada";
            }
        }
    }
}

VB.NET

Imports System
Imports DevExpress.Mvvm.DataAnnotations
Imports DevExpress.Mvvm
Imports DevExpress.Mvvm.POCO
Imports System.Linq
Imports DevExpress.DashboardCommon
Imports System.Collections.Generic

Namespace WPF_Dashboard_CustomParameters.ViewModels
    <POCOViewModel> _
    Public Class MyViewModel
        Protected Sub New()
            'Dashboard = new SampleDashboard(); 
            Dim dashboard_Renamed As New Dashboard()
            dashboard_Renamed.LoadFromXml("Data\SampleDashboard.xml")
            dashboard_Renamed.Parameters.Add(CreateParameter())
            dashboard_Renamed.DataSources(0).Filter = "[State] In (?parameterState)"
            Dashboard = dashboard_Renamed
        End Sub
        Public Overridable Property Dashboard() As DevExpress.DashboardCommon.Dashboard
        Private Function CreateParameter() As DashboardParameter
            Dim myDashboardParameter As New DashboardParameter()
            Dim staticListLookUpSettings1 As New StaticListLookUpSettings()
            myDashboardParameter.AllowMultiselect = True
            ' Parameter values displayed in the look-up editor.
            staticListLookUpSettings1.Values = New String() { "Alabama", "Ohio", "Utah" }
            myDashboardParameter.LookUpSettings = staticListLookUpSettings1
            myDashboardParameter.Name = "parameterState"
            myDashboardParameter.Type = GetType(String)
            ' Default parameter value.
            myDashboardParameter.Value = New List(Of String) From {"Ohio", "Utah"}
            Return myDashboardParameter
        End Function
        Public Sub OnCustomParameters(ByVal e As DevExpress.DashboardCommon.CustomParametersEventArgs)
            Dim customParameter = e.Parameters.FirstOrDefault(Function(p) p.Name = "parameterState")
            If customParameter IsNot Nothing Then
                ' Actual value used when retrieving data from the data source.
                customParameter.Value = "Nevada"
            End If
        End Sub
    End Class
End Namespace

Manage Parameters in the Dashboard State

A dashboard state stores the changes resulting from user interactions - selected master filter values, drill-down levels, selected dashboard item layers, and current parameter values. Use the DashboardState.Parameters property to access dashboard parameters.

Refer to the following article for more information on the Dashboard States: Manage the Dashboard State.

The following code snippet illustrates how to add a parameter state to the entire dashboard state. To specify the initial dashboard state when loading a dashboard, use the SetInitialDashboardState event.

C#

public MainWindow() {
    InitializeComponent();
    DashboardState state1 = CreateDashboardState();
    dashboardControl.SetDashboardState(state1);
}

public DashboardState CreateDashboardState() {
    DashboardState state = new DashboardState();
    DashboardParameterState parameterState = new DashboardParameterState() {
        Name = "CategoryNameParameter",
        Type = typeof(string),
        Value = "Beverages"
    };
    state.Parameters.Add(parameterState);
    return state;
}

private void DashboardControl_SetInitialDashboardState(object sender, DevExpress.DashboardWpf.SetInitialDashboardStateWpfEventArgs e) {
    e.InitialState = CreateDashboardState();
}

VB.NET

Public Sub New()
    InitializeComponent()
    Dim state1 As DashboardState = CreateDashboardState()
    dashboardControl.SetDashboardState(state1)
End Sub

Public Function CreateDashboardState() As DashboardState
    Dim state As New DashboardState()
    Dim parameterState As New DashboardParameterState() With {.Name = "CategoryNameParameter", .Type = GetType(String), .Value = "Beverages"}
    state.Parameters.Add(parameterState)
    Return state
End Function

Private Sub DashboardControl_SetInitialDashboardState(ByVal sender As Object, ByVal e As DevExpress.DashboardWpf.SetInitialDashboardStateWpfEventArgs)
    e.InitialState = CreateDashboardState()
End Sub