[Solved] VB multi-value Scheduler Provider error

[jonnyO]

Trying to implement a VB rendition of the multi-value resources example I'm getting error in my web.config.  Any ideas are appreciated.

web.config

    <configSections>
        <sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
            <sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
                <section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication" />
                <sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
                    <section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="Everywhere" />
                    <section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication" />
                    <section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" allowDefinition="MachineToApplication" />
                </sectionGroup>
            </sectionGroup>
        </sectionGroup>
        <sectionGroup name="telerik.web.ui">
            <section name="radScheduler" type="Telerik.Web.UI.RadSchedulerConfigurationSection, Telerik.Web.UI, PublicKeyToken=121fae78165ba3d4" allowDefinition="MachineToApplication" requirePermission="false" />
        </sectionGroup>
    </configSections>

...

    <telerik.web.ui>
        <radScheduler defaultAppointmentProvider="Integrated">
            <appointmentProviders>
                <add name="AppDbSchedulerProvider"
                    connectionStringName="dbMemberConnString"
                    type="AppScheduler.AppDbSchedulerProvider"
                    persistChanges="true" />
            </appointmentProviders>
        </radScheduler>
    </telerik.web.ui>

web.config error:
Parser Error Message: Cannot create an abstract class.

Source Error:

Line 202: <add name="AppDbSchedulerProvider" Line 203: connectionStringName="dbMemberConnString" Line 204: type="AppScheduler.AppDbSchedulerProvider" Line 205: persistChanges="true" /> Line 206: </appointmentProviders>

Provider code:

Imports System
Imports System.Collections.Generic
Imports System.Collections.Specialized
Imports System.Configuration
Imports System.Configuration.Provider
Imports System.Data
Imports System.Data.Common
Imports System.Data.SqlClient
Imports Telerik.Web.UI

Namespace AppScheduler
    Public MustInherit Class AppDbSchedulerProvider
        Inherits DbSchedulerProviderBase
        Public Overloads Overrides Function GetAppointments(ByVal owner As RadScheduler) As IEnumerable(Of Appointment)
            Dim appointments As New List(Of Appointment)()

            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [ClassID], [Subject], [Start], [End], [RecurrenceRule], [RecurrenceParentId] FROM [DbProvider_Classes]"

                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim apt As New Appointment()
                        apt.Owner = owner
                        apt.ID = reader("ClassID")
                        apt.Subject = Convert.ToString(reader("Subject"))
                        apt.Start = DateTime.SpecifyKind(Convert.ToDateTime(reader("Start")), DateTimeKind.Utc)
                        apt.[End] = DateTime.SpecifyKind(Convert.ToDateTime(reader("End")), DateTimeKind.Utc)
                        apt.RecurrenceRule = Convert.ToString(reader("RecurrenceRule"))
                        If Not apt.RecurrenceParentID Is Nothing Then
                            apt.RecurrenceParentID = reader("RecurrenceParentId")
                        End If

                        If apt.RecurrenceParentID <> Nothing Then
                            apt.RecurrenceState = RecurrenceState.Exception
                        ElseIf apt.RecurrenceRule <> String.Empty Then
                            apt.RecurrenceState = RecurrenceState.Master
                        End If

                        LoadResources(apt)
                        appointments.Add(apt)
                    End While
                End Using
            End Using

            Return appointments
        End Function

        'Public Overrides Sub Delete(ByVal owner As Telerik.Web.UI.RadScheduler, ByVal appointmentToDelete As Telerik.Web.UI.Appointment)
        Public Overrides Sub Delete(ByVal owner As RadScheduler, ByVal appointmentToDelete As Appointment)
            If Not PersistChanges Then
                Return
            End If
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                Using tran As DbTransaction = conn.BeginTransaction()
                    cmd.Transaction = tran
                    ClearClassStudents(appointmentToDelete.ID, cmd)
                    cmd.Parameters.Clear()
                    cmd.Parameters.Add(CreateParameter("@ClassID", appointmentToDelete.ID))
                    cmd.CommandText = "DELETE FROM [DbProvider_Classes] WHERE [ClassID] = @ClassID"
                    cmd.ExecuteNonQuery()
                    tran.Commit()
                End Using
            End Using
        End Sub

        Private Sub FillClassStudents(ByVal appointment As Appointment, ByVal cmd As DbCommand, ByVal classId As Object)
            For Each student As Resource In appointment.Resources.GetResourcesByType("Student")
                cmd.Parameters.Clear()
                cmd.Parameters.Add(CreateParameter("@ClassID", classId))
                cmd.Parameters.Add(CreateParameter("@StudentID", student.Key))
                cmd.CommandText = "INSERT INTO [DbProvider_ClassStudents] ([ClassID], [StudentID]) VALUES (@ClassID, @StudentID)"
                cmd.ExecuteNonQuery()
            Next
        End Sub

        Private Sub ClearClassStudents(ByVal classId As Object, ByVal cmd As DbCommand)
            cmd.Parameters.Clear()
            cmd.Parameters.Add(CreateParameter("@ClassID", classId))
            cmd.CommandText = "DELETE FROM [DbProvider_ClassStudents] WHERE [ClassID] = @ClassID"
            cmd.ExecuteNonQuery()
        End Sub

        Public Overrides Sub Insert(ByVal owner As RadScheduler, ByVal appointmentToInsert As Appointment)
            If Not PersistChanges Then
                Return
            End If
            Using conn As DbConnection = OpenConnection()
                Using tran As DbTransaction = conn.BeginTransaction()
                    Dim cmd As DbCommand = DbFactory.CreateCommand()
                    cmd.Connection = conn
                    cmd.Transaction = tran
                    PopulateAppointmentParameters(cmd, appointmentToInsert)
                    cmd.CommandText = " INSERT INTO [DbProvider_Classes]([Subject], [Start], [End], [TeacherID], [RecurrenceRule], [RecurrenceParentID]) VALUES (@Subject, @Start, @End, @TeacherID, @RecurrenceRule, @RecurrenceParentID)"
                    If TypeOf DbFactory Is SqlClientFactory Then
                        cmd.CommandText += Environment.NewLine + "SELECT SCOPE_IDENTITY()"
                    Else
                        cmd.ExecuteNonQuery()
                        cmd.CommandText = "SELECT @@IDENTITY"
                    End If
                    Dim identity As Integer = Convert.ToInt32(cmd.ExecuteScalar())
                    FillClassStudents(appointmentToInsert, cmd, identity)
                    tran.Commit()
                End Using
            End Using
        End Sub

        Public Overrides Sub Update(ByVal owner As RadScheduler, ByVal appointmentToUpdate As Appointment)
            If Not PersistChanges Then
                Return
            End If
            Using conn As DbConnection = OpenConnection()
                Using tran As DbTransaction = conn.BeginTransaction()
                    Dim cmd As DbCommand = DbFactory.CreateCommand()
                    cmd.Connection = conn
                    cmd.Transaction = tran
                    PopulateAppointmentParameters(cmd, appointmentToUpdate)
                    cmd.Parameters.Add(CreateParameter("@ClassID", appointmentToUpdate.ID))
                    cmd.CommandText = "UPDATE [DbProvider_Classes] SET [Subject] = @Subject, [Start] = @Start, [End] = @End, [TeacherID] = @TeacherID, [RecurrenceRule] = @RecurrenceRule, [RecurrenceParentID] = @RecurrenceParentID WHERE [ClassID] = @ClassID"
                    cmd.ExecuteNonQuery()
                    ClearClassStudents(appointmentToUpdate.ID, cmd)
                    FillClassStudents(appointmentToUpdate, cmd, appointmentToUpdate.ID)
                    tran.Commit()
                End Using
            End Using
        End Sub

        Public Overloads Overrides Function GetResourceTypes(ByVal owner As RadScheduler) As IEnumerable(Of ResourceType)
            Dim resourceTypes As ResourceType() = New ResourceType(2) {}
            resourceTypes(0) = New ResourceType("Teacher", False)
            resourceTypes(1) = New ResourceType("Student", True)
            Return resourceTypes
        End Function

        Private Sub LoadResources(ByVal apt As Appointment)
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.Parameters.Add(CreateParameter("@ClassID", apt.ID))
                cmd.CommandText = "SELECT [TeacherID] FROM [DbProvider_Classes] WHERE [ClassID] = @ClassID AND [TeacherID] IS NOT NULL"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    If reader.Read() Then
                        Dim teacher As Resource = apt.Owner.Resources.GetResource("Teacher", reader("TeacherID"))
                        apt.Resources.Add(teacher)
                    End If
                End Using
                cmd.Parameters.Clear()
                cmd.Parameters.Add(CreateParameter("@ClassID", apt.ID))
                cmd.CommandText = "SELECT [StudentID] FROM [DbProvider_ClassStudents] WHERE [ClassID] = @ClassID"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim student As Resource = apt.Owner.Resources.GetResource("Student", reader("StudentID"))
                        apt.Resources.Add(student)
                    End While
                End Using
            End Using
        End Sub

        Public Overloads Overrides Function GetResourcesByType(ByVal owner As RadScheduler, ByVal resourceType As String) As IEnumerable(Of Resource)
            Select Case resourceType
                Case "Teacher"
                    Return GetTeachers()
                Case "Student"
                    Return GetStudents()
                Case Else
                    Throw New InvalidOperationException("Unknown resource type: resourceType")
            End Select
        End Function

        Private Function GetTeachers() As IEnumerable(Of Resource)
            Dim resources As New List(Of Resource)()
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [TeacherID], [Name], [Phone] FROM [DbProvider_Teachers]"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim res As New Resource()
                        res.Type = "Teacher"
                        res.Key = reader("TeacherID")
                        res.Text = Convert.ToString(reader("Name"))
                        res.Attributes("Phone") = Convert.ToString(reader("Phone"))
                        resources.Add(res)
                    End While
                End Using
            End Using
            Return resources
        End Function

        Private Function GetStudents() As IEnumerable(Of Resource)
            Dim resources As New List(Of Resource)()
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [StudentID], [Name] FROM [DbProvider_Students]"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim res As New Resource()
                        res.Type = "Student"
                        res.Key = reader("StudentID")
                        res.Text = Convert.ToString(reader("Name"))
                        resources.Add(res)
                    End While
                End Using
            End Using
            Return resources
        End Function

        Private Sub PopulateAppointmentParameters(ByVal cmd As DbCommand, ByVal apt As Appointment)
            cmd.Parameters.Add(CreateParameter("@Subject", apt.Subject))
            cmd.Parameters.Add(CreateParameter("@Start", apt.Start))
            cmd.Parameters.Add(CreateParameter("@End", apt.[End]))
            Dim teacher As Resource = apt.Resources.GetResourceByType("Teacher")
            Dim teacherId As Object = Nothing
            If teacher <> Nothing Then
                teacherteacherId = teacher.Key
            End If
            cmd.Parameters.Add(CreateParameter("@TeacherID", teacherId))
            Dim rrule As String = Nothing
            If apt.RecurrenceRule <> String.Empty Then
                rrule = apt.RecurrenceRule
            End If
            cmd.Parameters.Add(CreateParameter("@RecurrenceRule", rrule))
            Dim parentId As Object = Nothing
            If apt.RecurrenceParentID <> Nothing Then
                parentId = apt.RecurrenceParentID
            End If
            cmd.Parameters.Add(CreateParameter("@RecurrenceParentId", parentId))
        End Sub


    End Class
End Namespace

Thanks

[T. Tsonev]

Hello,

Currently your class is defined as abstract (MustInherit) and that is why you are receiving the error. You should remove MustInherit from the class definition.

Kind regards,
Tsvetomir Tsonev
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[jonnyO]

Good. Now I'm getting:

Server Error in '/Web' Application.

---

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] Telerik.Web.UI.RadScheduler.BindResourcesFromProvider(IEnumerable`1 providedResourceTypes) +114 Telerik.Web.UI.RadScheduler.PerformSelect() +113 System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +70 Telerik.Web.UI.RadScheduler.EnsureDataBound() +48 Telerik.Web.UI.RadScheduler.CreateChildControls(Boolean bindFromDataSource) +55 Telerik.Web.UI.RadScheduler.CreateChildControls() +10 System.Web.UI.Control.EnsureChildControls() +87 System.Web.UI.Control.PreRenderRecursiveInternal() +50 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2041

With the following Provider code:

        Public Overloads Overrides Function GetResourceTypes(ByVal owner As RadScheduler) As IEnumerable(Of ResourceType)
            Dim resourceTypes As ResourceType() = New ResourceType(3) {}
            resourceTypes(0) = New ResourceType("EventUser", False)
            resourceTypes(1) = New ResourceType("EventType", False)
            resourceTypes(2) = New ResourceType("Attachments", True)
            Return resourceTypes
        End Function

        Public Overloads Overrides Function GetResourcesByType(ByVal owner As RadScheduler, ByVal resourceType As String) As IEnumerable(Of Resource)
            Select Case resourceType
                Case "EventUser"
                    Return GetUsers()
                Case "EventType"
                    Return GetTypes()
                Case "Attachments"
                    Return GetAttachments()
                Case Else
                    Throw New InvalidOperationException("Unknown resource type: resourceType")
            End Select
        End Function

        Private Function GetUsers() As IEnumerable(Of Resource)
            Dim resources As New List(Of Resource)()
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [SchedUserID], [SchedUserName] FROM [SchedAppProvider_User]"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim res As New Resource()
                        res.Type = "EventUser"
                        res.Key = reader("SchedUserID")
                        res.Text = Convert.ToString(reader("SchedUserName"))
                        'res.Attributes("Phone") = Convert.ToString(reader("Phone"))
                        resources.Add(res)
                    End While
                End Using
            End Using
            Return resources
        End Function

        Private Function GetTypes() As IEnumerable(Of Resource)
            Dim resources As New List(Of Resource)()
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [SchedTypeID], [SchedTypeLabel] FROM [SchedAppProvider_EventType]"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim res As New Resource()
                        res.Type = "EventType"
                        res.Key = reader("SchedTypeID")
                        res.Text = Convert.ToString(reader("SchedTypeLabel"))
                        'res.Attributes("Phone") = Convert.ToString(reader("Phone"))
                        resources.Add(res)
                    End While
                End Using
            End Using
            Return resources
        End Function

        Private Function GetAttachments() As IEnumerable(Of Resource)
            Dim resources As New List(Of Resource)()
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [SchedFileID], [SchedFileAttachmentLabel] FROM [SchedAppProvider_Attachment]"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim res As New Resource()
                        res.Type = "Attachments"
                        res.Key = reader("SchedFileID")
                        res.Text = Convert.ToString(reader("SchedFileAttachmentLabel"))
                        resources.Add(res)
                    End While
                End Using
            End Using
            Return resources
        End Function

        Private Overloads Sub LoadResources(ByVal apt As Appointment)
            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.Parameters.Add(CreateParameter("@SchedEventID", apt.ID))
                cmd.CommandText = "SELECT [SchedUserID] FROM [SchedAppProvider_Events] WHERE [SchedEventID] = @SchedEventID AND [SchedUserID] IS NOT NULL"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    If reader.Read() Then
                        Dim eventUser As Resource = apt.Owner.Resources.GetResource("EventUser", reader("SchedUserID"))
                        apt.Resources.Add(eventUser)
                    End If
                End Using
                cmd.Parameters.Clear()
                cmd.Parameters.Add(CreateParameter("@SchedEventID", apt.ID))
                cmd.CommandText = "SELECT [SchedFileID] FROM [SchedAppProvider_EventAttachments] WHERE [SchedEventID] = @SchedEventID"
                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim attachments As Resource = apt.Owner.Resources.GetResource("Attachments", reader("SchedFileID"))
                        apt.Resources.Add(attachments)
                    End While
                End Using
            End Using
        End Sub

        Public Overloads Overrides Function GetAppointments(ByVal owner As RadScheduler) As IEnumerable(Of Appointment)
            Dim appointments As New List(Of Appointment)()

            Using conn As DbConnection = OpenConnection()
                Dim cmd As DbCommand = DbFactory.CreateCommand()
                cmd.Connection = conn
                cmd.CommandText = "SELECT [SchedEventID], [Subject], [Start], [End], [RecurrenceRule], [RecurrenceParentId] FROM [SchedAppProvider_Events]"

                Using reader As DbDataReader = cmd.ExecuteReader()
                    While reader.Read()
                        Dim apt As New Appointment()
                        apt.Owner = owner
                        apt.ID = reader("SchedEventID")
                        apt.Subject = Convert.ToString(reader("Subject"))
                        apt.Start = DateTime.SpecifyKind(Convert.ToDateTime(reader("Start")), DateTimeKind.Utc)
                        apt.[End] = DateTime.SpecifyKind(Convert.ToDateTime(reader("End")), DateTimeKind.Utc)
                        apt.RecurrenceRule = Convert.ToString(reader("RecurrenceRule"))
                        If Not apt.RecurrenceParentID Is Nothing Then
                            apt.RecurrenceParentID = reader("RecurrenceParentId")
                        End If

                        If apt.RecurrenceParentID <> Nothing Then
                            apt.RecurrenceState = RecurrenceState.Exception
                        ElseIf apt.RecurrenceRule <> String.Empty Then
                            apt.RecurrenceState = RecurrenceState.Master
                        End If

                        LoadResources(apt)
                        appointments.Add(apt)
                    End While
                End Using
            End Using

            Return appointments
        End Function

There is no current data in any of the SQl tables... is this the problem?  If so what's the best way to code for null?

[jonnyO]

Thanks to another forum post I found via google "IEnumerable`1 providedResourceTypes)" search ... simple mistake "New ResourceType(3)" should have been 2

Thanks for your time