How to: Provide Data for ObjectDataSource with a Fill Service

• Jun 17, 2019
• 3 minutes to read

This example shows how to bind the ASP.NET Web Forms Dashboard Control to the Object Data Source and supply it with data using a custom fill service. To do this, you need to implement an IObjectDataSourceCustomFillService interface. In this example, the ObjectDataSourceFillParameters.Parameters collection of dashboard parameters is used to load the specified number of records.

Note

A complete sample project is available at ASPxDashboard - How to Use a Service to Fill the ObjectDataSource.

CustomObjectDataSourceCustomFillService.cs

public class CustomObjectDataSourceCustomFillService : IObjectDataSourceCustomFillService {
    public object GetData(DashboardObjectDataSource dataSource, ObjectDataSourceFillParameters fillParameters) {
        if (fillParameters.DataFields == null || fillParameters.DataFields.Length == 0) {
            return null;
        }

        List<SalesPersonData> data = DataGenerator.Data;

        DataTable table = new DataTable();
        foreach (string field in fillParameters.DataFields) {
            table.Columns.Add(field);
        }

        int NumberOfRecordsToRetrieveParameter = (int)(fillParameters.Parameters.FirstOrDefault(i => i.Name == "NumberOfRecords")?.Value);
        int NumberOfRecordsToRetrieve = NumberOfRecordsToRetrieveParameter <= data.Count ? NumberOfRecordsToRetrieveParameter : data.Count;

        for (int i = 0; i < NumberOfRecordsToRetrieve; i++) {
            object[] row = new object[fillParameters.DataFields.Length];
            for (int j = 0; j < fillParameters.DataFields.Length; j++) {
                row[j] = GetPropertyValue(data[i], fillParameters.DataFields[j]);
            }
            table.Rows.Add(row);
        }
        return table.DefaultView;
    }
    object GetPropertyValue(SalesPersonData obj, string propName) {
        return propName == "SalesPerson" ? (object)obj.SalesPerson : (object)obj.Quantity;
    }
}

Default.aspx.cs

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

namespace DXWebApplication5 {
    public partial class Default1 : System.Web.UI.Page {
        protected void Page_Load(object sender, EventArgs e) {
            DashboardFileStorage dashboardFileStorage = new DashboardFileStorage("~/App_Data/Dashboards");
            ASPxDashboard1.SetDashboardStorage(dashboardFileStorage);

            DataSourceInMemoryStorage dataSourceStorage = new DataSourceInMemoryStorage();
            DashboardObjectDataSource objDataSource = new DashboardObjectDataSource("Object Data Source", typeof(SalesPersonData));
            dataSourceStorage.RegisterDataSource("objDataSource", objDataSource.SaveToXml());
            ASPxDashboard1.SetDataSourceStorage(dataSourceStorage);

            ASPxDashboard1.ServiceContainer.AddService(typeof(IObjectDataSourceCustomFillService), new CustomObjectDataSourceCustomFillService());
        }
    }
}

CustomObjectDataSourceCustomFillService.vb

Public Class CustomObjectDataSourceCustomFillService
    Implements IObjectDataSourceCustomFillService

    Public Function GetData(ByVal dataSource As DashboardObjectDataSource, ByVal fillParameters As ObjectDataSourceFillParameters) As Object Implements IObjectDataSourceCustomFillService.GetData
        If fillParameters.DataFields Is Nothing OrElse fillParameters.DataFields.Length = 0 Then
            Return Nothing
        End If

        Dim data As List(Of SalesPersonData) = DataGenerator.Data

        Dim table As New DataTable()
        For Each field As String In fillParameters.DataFields
            table.Columns.Add(field)
        Next field

        Dim NumberOfRecordsToRetrieveParameter As Integer = CInt(Fix(If(fillParameters.Parameters.FirstOrDefault(Function(i) i.Name = "NumberOfRecords") Is Nothing, Nothing, fillParameters.Parameters.FirstOrDefault(Function(i) i.Name = "NumberOfRecords").Value)))
        Dim NumberOfRecordsToRetrieve As Integer = If(NumberOfRecordsToRetrieveParameter <= data.Count, NumberOfRecordsToRetrieveParameter, data.Count)

        For i As Integer = 0 To NumberOfRecordsToRetrieve - 1
            Dim row(fillParameters.DataFields.Length - 1) As Object
            For j As Integer = 0 To fillParameters.DataFields.Length - 1
                row(j) = GetPropertyValue(data(i), fillParameters.DataFields(j))
            Next j
            table.Rows.Add(row)
        Next i
        Return table.DefaultView
    End Function
    Private Function GetPropertyValue(ByVal obj As SalesPersonData, ByVal propName As String) As Object
        Return If(propName = "SalesPerson", DirectCast(obj.SalesPerson, Object), DirectCast(obj.Quantity, Object))
    End Function
End Class

Default.aspx.vb

Imports DevExpress.DashboardCommon
Imports DevExpress.DashboardWeb
Imports System

Namespace DXWebApplication5
    Partial Public Class Default1
        Inherits System.Web.UI.Page

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
            Dim dashboardFileStorage As New DashboardFileStorage("~/App_Data/Dashboards")
            ASPxDashboard1.SetDashboardStorage(dashboardFileStorage)

            Dim dataSourceStorage As New DataSourceInMemoryStorage()
            Dim objDataSource As New DashboardObjectDataSource("Object Data Source", GetType(SalesPersonData))
            dataSourceStorage.RegisterDataSource("objDataSource", objDataSource.SaveToXml())
            ASPxDashboard1.SetDataSourceStorage(dataSourceStorage)

            ASPxDashboard1.ServiceContainer.AddService(GetType(IObjectDataSourceCustomFillService), New CustomObjectDataSourceCustomFillService())
        End Sub
    End Class
End Namespace