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    Using Linq as datasource (VB.Net / netframework)

    Note

    This demo is available in your FlexCel installation at <FlexCel Install Folder>\samples\vb\VS2022\netframework\20.Reports\22.Linq and also at https:​//​github.​com/​tmssoftware/​TMS-​FlexCel.​NET-​demos/​tree/​master/​vb/​VS2022/​netframework/​Modules/​20.​Reports/​22.​Linq

    Overview

    THIS DEMO NEEDS .NET 3.5 OR NEWER.

    Most of the demos here use datasets as datasources. This is just for convenience, because Linq is not supported in .NET 2.0 and so if we used Linq those demos wouldn't work for everybody, and also because the focus is in the Excel templates, not so much in the data layer. But you can use any IQueryable<T> collection as a datasource in a FlexCel report, and this is what we will show here.

    Concepts

    • How to run a report from a List<> of objects.

    • When using IQueryable<T> as datasource, you can use any public property of T in the report. So if type T has a public property "LastName", you can access it with <#dt.LastName>.

    • Master detail with implicit relationships. When a public property of a collection of objects is other collection of objects, the property is considered as a detail of the main collection. In this example "Elements" is a property of "Categories", and so there is an implicit relationship between them.

    • Master detail with explicit relationships. While when using LINQ you will normally use implicit relationships, you can also relate any two collections of objects with a relationship, as you could with datasets. In this example, "ElementName" is explicitly related to "Elements" with a call to FlexCelReport.AddRelationship.

    Files

    AssemblyInfo.vb

    Imports System.Reflection
    Imports System.Runtime.CompilerServices
    
    '
    ' General Information about an assembly is controlled through the following 
    ' set of attributes. Change these attribute values to modify the information
    ' associated with an assembly.
    '
    <Assembly: AssemblyTitle("")>
    <Assembly: AssemblyDescription("")>
    <Assembly: AssemblyConfiguration("")>
    <Assembly: AssemblyCompany("")>
    <Assembly: AssemblyProduct("")>
    <Assembly: AssemblyCopyright("(c) 2002 - 2014 TMS Software")>
    <Assembly: AssemblyTrademark("")>
    <Assembly: AssemblyCulture("")>
    
    '
    ' Version information for an assembly consists of the following four values:
    '
    '      Major Version
    '      Minor Version 
    '      Build Number
    '      Revision
    '
    ' You can specify all the values or you can default the Revision and Build Numbers 
    ' by using the '*' as shown below:
    
    <Assembly: AssemblyVersion("6.2.1.0")>
    
    '
    ' In order to sign your assembly you must specify a key to use. Refer to the 
    ' Microsoft .NET Framework documentation for more information on assembly signing.
    '
    ' Use the attributes below to control which key is used for signing. 
    '
    ' Notes: 
    '   (*) If no key is specified, the assembly is not signed.
    '   (*) KeyName refers to a key that has been installed in the Crypto Service
    '       Provider (CSP) on your machine. KeyFile refers to a file which contains
    '       a key.
    '   (*) If the KeyFile and the KeyName values are both specified, the 
    '       following processing occurs:
    '       (1) If the KeyName can be found in the CSP, that key is used.
    '       (2) If the KeyName does not exist and the KeyFile does exist, the key 
    '           in the KeyFile is installed into the CSP and used.
    '   (*) In order to create a KeyFile, you can use the sn.exe (Strong Name) utility.
    '       When specifying the KeyFile, the location of the KeyFile should be
    '       relative to the project output directory which is
    '       %Project Directory%\obj\<configuration>. For example, if your KeyFile is
    '       located in the project directory, you would specify the AssemblyKeyFile 
    '       attribute as [assembly: AssemblyKeyFile("..\\..\\mykey.snk")]
    '   (*) Delay Signing is an advanced option - see the Microsoft .NET Framework
    '       documentation for more information on this.
    '
    <Assembly: AssemblyDelaySign(False)>
    <Assembly: AssemblyKeyFile("")>
    <Assembly: AssemblyKeyName("")>
    

    Form1.Designer.vb

    Imports System.Collections
    Imports System.ComponentModel
    Imports System.IO
    Imports System.Reflection
    Imports FlexCel.Core
    Imports FlexCel.XlsAdapter
    Imports FlexCel.Report
    Namespace Linq
        Partial Public Class mainForm
            Inherits System.Windows.Forms.Form
    
            Private WithEvents button1 As System.Windows.Forms.Button
            Private saveFileDialog1 As System.Windows.Forms.SaveFileDialog
            Private label1 As System.Windows.Forms.Label
            Private WithEvents btnCancel As System.Windows.Forms.Button
            ''' <summary>
            ''' Required designer variable.
            ''' </summary>
            Private components As System.ComponentModel.Container = Nothing
    
            ''' <summary>
            ''' Clean up any resources being used.
            ''' </summary>
            Protected Overrides Sub Dispose(ByVal disposing As Boolean)
                If disposing Then
                    If components IsNot Nothing Then
                        components.Dispose()
                    End If
                End If
                MyBase.Dispose(disposing)
            End Sub
    
            #Region "Windows Form Designer generated code"
            ''' <summary>
            ''' Required method for Designer support - do not modify
            ''' the contents of this method with the code editor.
            ''' </summary>
            Private Sub InitializeComponent()
                Me.button1 = New System.Windows.Forms.Button()
                Me.saveFileDialog1 = New System.Windows.Forms.SaveFileDialog()
                Me.label1 = New System.Windows.Forms.Label()
                Me.btnCancel = New System.Windows.Forms.Button()
                Me.SuspendLayout()
                ' 
                ' button1
                ' 
                Me.button1.Anchor = (CType((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles))
                Me.button1.BackColor = System.Drawing.Color.Green
                Me.button1.ForeColor = System.Drawing.Color.White
                Me.button1.Location = New System.Drawing.Point(152, 88)
                Me.button1.Name = "button1"
                Me.button1.Size = New System.Drawing.Size(112, 23)
                Me.button1.TabIndex = 0
                Me.button1.Text = "GO!"
                Me.button1.UseVisualStyleBackColor = False
    '           Me.button1.Click += New System.EventHandler(Me.button1_Click)
                ' 
                ' saveFileDialog1
                ' 
                Me.saveFileDialog1.Filter = "Excel Files|*.xls"
                Me.saveFileDialog1.RestoreDirectory = True
                ' 
                ' label1
                ' 
                Me.label1.Location = New System.Drawing.Point(24, 24)
                Me.label1.Name = "label1"
                Me.label1.Size = New System.Drawing.Size(272, 24)
                Me.label1.TabIndex = 2
                Me.label1.Text = "Press ""GO"" to create a report from a List<> of objects."
                ' 
                ' btnCancel
                ' 
                Me.btnCancel.Anchor = (CType((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles))
                Me.btnCancel.BackColor = System.Drawing.Color.FromArgb((CInt((CByte(192)))), (CInt((CByte(0)))), (CInt((CByte(0)))))
                Me.btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel
                Me.btnCancel.ForeColor = System.Drawing.Color.White
                Me.btnCancel.Location = New System.Drawing.Point(272, 88)
                Me.btnCancel.Name = "btnCancel"
                Me.btnCancel.Size = New System.Drawing.Size(112, 23)
                Me.btnCancel.TabIndex = 3
                Me.btnCancel.Text = "Cancel"
                Me.btnCancel.UseVisualStyleBackColor = False
    '           Me.btnCancel.Click += New System.EventHandler(Me.btnCancel_Click)
                ' 
                ' mainForm
                ' 
                Me.AutoScaleDimensions = New System.Drawing.SizeF(6F, 13F)
                Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
                Me.ClientSize = New System.Drawing.Size(416, 133)
                Me.Controls.Add(Me.btnCancel)
                Me.Controls.Add(Me.label1)
                Me.Controls.Add(Me.button1)
                Me.Name = "mainForm"
                Me.Text = "Linq Reports"
                Me.ResumeLayout(False)
    
            End Sub
            #End Region
        End Class
    End Namespace
    

    Form1.vb

    Imports System.Collections
    Imports System.ComponentModel
    Imports System.IO
    Imports System.Reflection
    Imports FlexCel.Core
    Imports FlexCel.XlsAdapter
    Imports FlexCel.Report
    
    
    Namespace Linq
        ''' <summary>
        ''' Summary description for Form1.
        ''' </summary>
        Partial Public Class mainForm
            Inherits System.Windows.Forms.Form
    
            Public Sub New()
                InitializeComponent()
            End Sub
    
            Private Sub button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles button1.Click
                AutoRun()
            End Sub
    
            Public Sub AutoRun()
                Using report As New FlexCelReport(True)
                    LoadTables(report)
    
                    Dim DataPath As String = Path.Combine(Path.Combine(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), ".."), "..") & Path.DirectorySeparatorChar
    
                    If saveFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
                        report.Run(DataPath & "Linq.template.xls", saveFileDialog1.FileName)
    
                        If MessageBox.Show("Do you want to open the generated file?", "Confirm", MessageBoxButtons.YesNo) = System.Windows.Forms.DialogResult.Yes Then
                            Process.Start(saveFileDialog1.FileName)
                        End If
                    End If
                End Using
            End Sub
    
            Private Sub LoadTables(ByVal report As FlexCelReport)
                Dim Categories As New List(Of Categories)()
                Dim Animals As New Categories("Animals")
                Animals.Elements.Add(New Elements(1, "Penguin"))
                Animals.Elements.Add(New Elements(2, "Cat"))
                Animals.Elements.Add(New Elements(3, "Unicorn"))
                Categories.Add(Animals)
    
                Dim Flowers As New Categories("Flowers")
                Flowers.Elements.Add(New Elements(4, "Daisy"))
                Flowers.Elements.Add(New Elements(5, "Rose"))
                Flowers.Elements.Add(New Elements(6, "Orchid"))
                Categories.Add(Flowers)
    
                report.AddTable("Categories", Categories)
                'We don't need to call AddTable for elements since it is already added when we add Categories.
    
    
                Dim ElementNames As New List(Of ElementName)()
                ElementNames.Add(New ElementName(1, "Linus"))
                ElementNames.Add(New ElementName(1, "Gerard"))
                ElementNames.Add(New ElementName(2, "Rover"))
                ElementNames.Add(New ElementName(3, "Mike"))
                ElementNames.Add(New ElementName(5, "Rosalyn"))
                ElementNames.Add(New ElementName(5, "Monica"))
                ElementNames.Add(New ElementName(6, "Lisa"))
    
                report.AddTable("ElementName", ElementNames)
                'ElementName doesn't have an intrinsic relationship with categories, so we will have to manually add a relationship.
                'Non intrinsic relationships should be rare, but we do it here to show how it can be done.
                report.AddRelationship("Elements", "ElementName", "ElementID", "ElementID")
            End Sub
    
            Private Sub btnCancel_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCancel.Click
                Close()
            End Sub
        End Class
    
        Public Class Categories
            'Public properties can be used in reports.
            Private privateName As String
            Public Property Name() As String
                Get
                    Return privateName
                End Get
                Private Set(ByVal value As String)
                    privateName = value
                End Set
            End Property
    
            'Elements is in master-detail relationship with this element, even when we don't explicitly add a relationship. 
            'Relationship is inferred because Elements is a property of this object
            Private privateElements As List(Of Elements)
            Public Property Elements() As List(Of Elements)
                Get
                    Return privateElements
                End Get
                Private Set(ByVal value As List(Of Elements))
                    privateElements = value
                End Set
            End Property
    
            Public Sub New(ByVal name As String)
                Me.Name = name
                Elements = New List(Of Elements)()
            End Sub
    
        End Class
    
        Public Class Elements
            'We will relate this property with the table of colors by adding a relationship.
            Private privateElementID As Integer
            Public Property ElementID() As Integer
                Get
                    Return privateElementID
                End Get
                Private Set(ByVal value As Integer)
                    privateElementID = value
                End Set
            End Property
    
            Private privateName As String
            Public Property Name() As String
                Get
                    Return privateName
                End Get
                Private Set(ByVal value As String)
                    privateName = value
                End Set
            End Property
    
    
            Public Sub New(ByVal elementID As Integer, ByVal name As String)
                Me.Name = name
                Me.ElementID = elementID
            End Sub
    
        End Class
    
        Public Class ElementName
            Private privateElementID As Integer
            Public Property ElementID() As Integer
                Get
                    Return privateElementID
                End Get
                Private Set(ByVal value As Integer)
                    privateElementID = value
                End Set
            End Property
            Private privateName As String
            Public Property Name() As String
                Get
                    Return privateName
                End Get
                Private Set(ByVal value As String)
                    privateName = value
                End Set
            End Property
    
            Public Sub New(ByVal elementID As Integer, ByVal name As String)
                Me.ElementID = elementID
                Me.Name = name
            End Sub
        End Class
    
    End Namespace
    

    Program.vb

    Namespace Linq
        Friend NotInheritable Class Program
    
            Private Sub New()
            End Sub
    
            ''' <summary>
            ''' The main entry point for the application.
            ''' </summary>
           <STAThread> _
            Shared Sub Main()
                Application.EnableVisualStyles()
                Application.SetCompatibleTextRenderingDefault(False)
                Application.Run(New mainForm())
            End Sub
        End Class
    End Namespace
    
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